Automating processes

Recently I have been working on my AWS Architect certification. Rather than just grinding through the training material and practice exams I thought I should actually build something and journal my process. I have done this internally for Commvault but wanted to do an external blog as well so that if I left Commvault I would have a copy of my notes.

The first step in building something is documenting the project including the goals, objectives, and components that will be needed. Initially I interviewed the person that I am building this project for and drew everything on paper (I know, old school). From there I transcribed it into an AWS architecture diagram using LucidChart.

The goal of the project is to take a zip file that is an aggregation of ECGs performed on student athletes and upload it into S3. Once the zip file is uploaded it kicks off a process that unzips the files and copies them to another folder inside the bucket. From here these files are copies to Dropbox and a notification is sent to one or more email boxes or text messages. From this notification a Cardiologist interprets the results and responds to the email or text. Once the response is received the interpreted files are transferred from Dropbox back into S3 and sorted according to the school that was screened. Students that were marked as low risk are stamped with a low risk label. Students that were marked needing a follow up or high risk are placed into a different folder for manual processing and a notification is sent via email and/or text requesting for manual intervention.

The first step in the process is taking a zip file that was uploaded into S3 and processing it. Fortunately we have the ability to launch processes when a file is uploaded into S3 with the Lambda functions. A good place to start learning about this is https://docs.aws.amazon.com/lambda/latest/dg/with-s3-example.html where the tutorial talks about how to create a Lambda function and tie it to changes to a specific bucket. This also required creating an IAM role that allows a Lambda function to read and write an S3 bucket.

Step 1) Create IAM Role. This id done by going to the IAM console and selecting Roles at the left of the screen. We want to click on the Create role blue button near the middle of the screen.



We select the Lambda function and click Next:Permissions at the bottom of the screen.

To make things easy we select AmazonS3FullAccess. What we want is the ability to read and write objects in an S3 bucket. We need to type in S3 in the Filter policies then select the box next to AmazonS3FullAccess.

We skip the tags role and go to Review. Here we enter a Role name. We will call it gbgh-processing. Once we enter this information we click Create role at the bottom right of the screen.

At this point we have a role that allows our Lambda function to access S3 objects and manipulate them.

Step 2) The next step is to create a bucket that we will upload files into. This is done by going to the S3 console and creating a bucket. The bucket must be in the same zone that we create our Lambda function. In our example we will create a bucket called gbgh-test and put it in the US East region.

We click on the Create bucket blue button at the top left of the screen. The bucket name needs to be unique and we want the US East region. We don’t want to copy settings from other buckets and will configure the options on our own. We will be using gbgh-test as the bucket name.

We will go with the default options and clear all of the permissions as shown below. We want to open up public access for our bucket because a variety of people long term will be uploading files into the bucket. We can control access through other mechanisms at a later date.

From here we click Next and Create Bucket on the next screen.

We should see our bucket ready and available in the S3 bucket list.

Step 3) create a Lambda function that receives S3 object changes so that we can process the files and do something with it. To do this we go to the Lambda function console.

Notice that we have a few functions already defined. Some are Java. Some are Node.js. Some are Python. We will be creating a Python 2.7 binary so that we can use the boto3 library. This pre-defined library allows us to quickly and easily manipulate objects in a bucket and call other AWS services like email and queue services. To start we click on the orange Create function button at the top right of the screen.

We will Author from scratch our code since we have some simple code that we can work from. We will call the function gbgh-test and select Python 2.7 as the runtime. We will select the gbgh-processing role to give our function access to the S3 bucket that we created.

When we click on the Create function it drops us into the Designer tool for editing and testing our Lambda function. The first thing that we want to do is add an S3 trigger to link S3 objects to our function.

The trigger is found under the Designer – Add triggers list. Scroll down and click on S3. It will show that Configuration is required and we will need to scroll down to configure the trigger. From here we will select the bucket and Event type. We are looking for create events which indicates that someone uploaded a file for us to process. We select the gbgh-test bucket and stick with the All object create events.

After clicking on Add we nativate to the gbgh-test icon to see the Function code where we can edit the function and test code that we want. The default handler does not do what we want so we need to replace this code.

For our function we are going to start simple. We will handle a create event, pull the bucket name from the event handler, pull the file name that was uploaded, and print all of the items in the bucket for testing. The code starts with an import of the boto3 library. We create a handle into S3 with the boto3.resource(‘s3’) library call. The lambda_handler is launched when a file is created in our S3 bucket. From here we print some diagnostics that the handler was called then walk the object list in the bucket and print the object names. From here we return and terminate the Lambda function. Sample code for this can be found at lambda_function_s3_upload.js

The next step is to create a test event to simulate a file upload. We do this by clicking on the Select a test event pulldown and selecting Configure test events.

For the test event we need to simulate an ObjectCreated:Put call or an https PUT that causes a file to be uploaded to our S3 bucket. We need to define the arn for our bucket and bucket name as well as an object name (gbgh.zip) that we need to actually create in our gbgh-test bucket. We define the event name as gbghTest and paste in our simulated event call. The code for this can be found at testS3Put.json

The data at the bottom of the screen are just curly brackets to finish out the record definition. From here we click on Create (I had to scroll down to see it) to create our test function. At this point we can select gbghTest and click on the Test button at the top right of the screen. When we first tried this it failed with an error. We had to add two lines to import the json and urllib functions since we call them to process the keys or object names. Once we make these changes we see that the status came back Succeeded and we get an empty listing of gbgh-test if we scroll down in the Execution results screen.

We can upload our gbgh.zip file into our gbgh-test bucket and it should appear at the bottom of the Execution results screen.

To summarize, we have a Lambda function that gets launched when we upload a file into an S3 bucket. Currently the function just prints a directory of the bucket by listing all of the objects that it contains. We had to create an IAM policy so that our function can interact with S3. In the next blog post we will do some processing of this zip file and send some notifications once the zip file is processed.

mason jar bourbon

I taste tested a few of my mason jar aging experiments this weekend and the results were surprising.

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The Whistlestop with a light char was my favorite. It almost makes me want to try an uncharred piece of oak just to see what it does. The flavor changes after three weeks into a smoother bourbon. The color is a light golden brown and gets darker and darker every week.

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The light char got rid of the acidic after bite that the white whiskey has and makes it a little smoother. It still smells very much like moonshine but has other smells associated with it.

The dark char has a smoky almost burnt flavor. My hopes are that this will fade over time. I could tell a big difference between the light and dark char. I might need to experiment with different levels of char and how long the chips are allowed to cook in the cast iron box to get different levels of char.

The hickory wood is my least favorite. The flavor was not what I expected and took on almost a rancid flavor. I was glad that I had crackers close by. The flavor was not smooth and not something that I would repeat. I will give it a few more months but I have little or no hope that this will work. It does make me want to try other woods to see what the differences are. I do have some apple and pecan chips that might be worth experimenting with.

I decided to fill my 5 liter cask with Weller Special Reserve and see if I could smooth the flavor with the oak barrel. I first hydrated the cask with water for a week and rinsed it out. I then put three 1.5 liter bottles in the cask and let it sit for a week. The flavor changed but not as much as the mason jar experiments. My guess is that the cask is a light char. Since I got it as a present I have no clue how much char there is inside. I like the flavor and look forward to seeing how it mellows as the weeks go on.

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Status update:

mason jars: 3 weeks on the shelf, flavor changed after week 1.

oak cask: 1 week on the shelf, flavor smoother after 1 week.

 

different kind of homebrew

For Christmas I got a small keg to age something in. I did not want to just dive straight into aging bourbon without experimenting first so I did a little research.

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It turns out that aging distilled spirits is not something new but has been around since the history of our country. Who knew? Some of the interesting sites that I found suggested first trying a small quantity in a mason jar with wood charred and placed in the jar with the whiskey. A few of those sites are

There are also a ton of companies that will “help” you start your project.

So loaded with research material and a bunch of mason jars, I thought what did I have to loose?

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I went ahead and collected what I thought would be all of the necessary components. Given that I love to experiment I wanted to try oak and hickory chips as well as white whiskey, moonshine, and bourbon as the base.

The two types of chips that I got were Jack Daniels Oak Barrel chips used for BBQ smoking (Ace Hardware) and Hickory chips for flavoring.

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The blogs that I read suggested burning the chips and placing them in a mason jar with the white whiskey. I wanted to do this in a controlled way so I measured 2 cups of white whiskey and 50 grams of chips. I experimented burning the chips with a dark and light char as well as burning them by hand with a butane torch and with a smoking box in side a grill.

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The three liquids that are being experimented with are White Whiskey, Moonshine, and Weller Reserve Bourbon.

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First I put light charred chips into a mason jar and added 2 cups of White Whiskey. Everything that I read suggested getting something with the highest proof because it will absorb the flavor of the wood better than a lower, watered down concentration. The Rio Brazos Whistlestop is 90 proof. The Palmetto Moonshine is 105 proof. The Weller Special Reserve is 90 proof.

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I put blue painters tape on each jar to label if it was light or dark char, if it was hickory or oak chips, and if it was Weller, Whistlestop, or Moonshine.

Everything that I read said don’t expect much change over the first week or two. The color changes very quickly but the flavor does not change. I stored the mason jars in the garage because the temperature variation helps the wood absorb and express the whiskey. The smaller container ages everything at a faster rate since you have a higher liquid to wood ratio. What would typically take 3 years should take 2-3 months. My hope is to sample the different containers and see if it gets better over the weeks/months.

I did sample the Weller a week later to see if the flavor changed and was very surprised how much it changed. The flavor took on a smoky and woody taste. I am not sure if it is something that I like but it had less of an acidic after burn but also tasted oversmoked. My hope is that it will settle down and smooth out as the liquid pulls from deeper and deeper in the wood.

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After my initial experiment I did put samples on the shelf and filled my 5 liter cask with Weller. Given that Weller and Whistlestop costs the same at our local liquor store I wanted to start with aged bourbon and see if I could change the flavor.

It is important to look at the economics

Simple experiment – $60, mason jars, smoking box, chips, 1 liter liqueur of choice.

Full Barrel – $260, oak barrel, 4.5 liter liqueur of choice, smoking box, chips.

I also ordered some test tubes with cork stoppers ($12 for a dozen) so that I could pull half a shot a week to test the taste. I label the corks with a number representing the week that it was pulled and plan on doing a vertical sampling after month three.

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quadcopter assembly – part 3

We will continue our journey into building a quadcopter by working on the flight controller circuit.

quadcopter

The flight controller that we will be using is the Acro Naze32 Flight Controller ($31). This controller requires a little assembly prior to using because it comes in parts. The surface mount parts are on the board but the headers need to be soldered to the circuit. Naze32

The board comes with a straight or angled connector. It is confusing which you want to use. If you get the board without the barometer module it is recommended to use the straight connector. If you get the board with the barometer chip then the angled connector is probably best so that you can put a GPS unit in the same space on top of the quadcopter.

In my opinion, the design of the board is counter intuitive and has some design flaws. The kit comes with three connectors that need to be soldered onto the board. The two headers that go through holes on the board are relatively easy even though one of the connectors is millimeters from a surface mount component. What makes no sense to me is the gold connector that you have to side mount pins to. A connection like this typically is easy to mess up and break under vibration. Why put an edge connector here and not put through holes to solder? The pin towards the middle of the board is close to three surface mount components. Overall, I think that the design is somewhat silly. Why ship extra headers at extra cost but skimp on board size and not put through holes for higher reliability? The connector that I am openly ranting about is the connector shown on the far left on the picture below (connected to pins 4,5,6,7, and 8).

flight_controller_2 flight_controller_1

The next step is to lock down all of the screws mounting the arms to the Q450. This is relatively simple and requires a 2.0mm allen wrench.  Once these are locked down we screw the prop mounts onto the motor with a 2.3mm allen wrench. The two photos below show the screws going into the motor then the prop spacer and nut to hold the prop.

motor_prop_holdermotor_with_nut

The next step is to mount the flight controller to the quadcopter assembly. The assembly has an arrow on top pointing to the direction of travel. The circuit board also has an arrow pointing to the direction of travel. We are going to mount the flight controller board on top of the quadcopter using double sided tape (we could use screws and spacers if desired because the holes are on the board and on the quadcopter). If you use screws and spacers you need grommets to reduce vibration. The double sided tape tends to dampen vibration and keep the system from changing during flight. It is CRITICAL that you use enough tape to isolate the electrical components and the board. It is also CRITICAL that the arrows align with each other. This keeps the software and remote controller aligned. Moving the board off axis will cause imbalance in the motor controller and flight controls.

flight_controller_alignment controller_mounting

Once we have the flight controller mounted, we can mount the battery between the two layers. This is done with a velcro strap to allow for quick release. We loop the strap through the two rectangular holes on the bottom board.

battery_1 battery_2

The next step is a little difficult. We need to take the middle wire (red wire) from the 3 pin connector coming off the speed controller and pull it out. We don’t want all four speed controllers providing power to the flight controller. We take the middle pin out from three of our speed controllers and cover them with shrink fit tubing. The reason why we use heat shrink rather than cutting the wire is to have redundant systems to use in the future. We can always take the tubing off and put the cable back into the connector.

connector_2 connector_1

Now that we have three of the connectors modified, we can plug these connectors into the flight controller.

In the class we took a diversion and downloaded the baseflight-configurator using Google Chrome Store. This is done by searching for baseflight-configurator and installing the plug-in. Once the plug-in is installed, launch it and install the USB driver for the computer that you are using. Once this is installed you should be able to connect to the flight controller from a USB to mini-USB connector.

fc_to_laptop

With this we have a connection to the flight controller from our laptop. If you click on the connect with the port configured to be at 115200 speed you should get a green Disconnect button rather than a red Connect button. As you move the quadcopter around you should see the motion mirrored on the laptop.

The first thing that we need to do once we have the baseflight-configurator running, we need to update the firmware and flash it to the controller. We download the firmware from github then flash it to the controller.

From this we go into the configurator and setup things like motor rotation direction, throttle max and mins. Make sure all features are turned off. We then save and it updates the flight controller firmware.

The class instructions starting at page 113 have screen shots of all of these configurations along with explanation of all options and selections.

One side discussion was that a mobius 1080p camera ($82) is a good add on. It allows you to record a flight and does not add much weight to the quadcopter.

Once we have the software operational, we can connect the speed controllers (and thus the motors) to the flight controller. Looking at the configuration diagram for a Quad X configuration we notice that the bottom right motor is channel 1, top right is channel 2, bottom left is channel 3, and the top left is channel 4. This corresponds to the pin block at the front of the flight controller (front being where the arrow is pointing). The numbering starts from the right side with pin 1 and goes to pin 6 at the left. The orange cable is the signal, the red pin (only connected via channel 2) is power, and the brown wires are ground. You can verify this by looking next to pins 6 and see the “-“, “+”, and square wave on the circuit board. In the photo below we have the speed controllers plugged into channels 1, 2, 3, and 4 with channels 5 and 6 unconnected.

fc_motor

 

The next step is to plug back into the laptop and test the rotation direction of the motors. By going into the motor testing tab we can energize the motors and rotate them at different speeds. This allows us to test the direction of the motor rotation and reverse the red and yellow wires going to the motor to have them rotate in the direction that we want.

The cool thing at this point is that we have a working quadcopter. We have a battery pack that is communicating to the flight controller. The flight controllers are pushing power to the speed controllers thus turning the motors. The only thing that we are missing is the rc controller to control motor speed and flight. We are using the laptop as the rc controller for calibration.

The next step in the class is to get your rc transmitter paired with the on-board receiver. Given that we had a Spektrum transmitter and receiver, it was different from everyone else. For ours we had to follow the directions in the Spektrum manual. Page 10 shows how to bind the receiver with the transmitter. We used the bind plug method (Binding Using the Receiver and Receiver Battery). We plugged the bind plug into the bind section of the receiver and unplugged connector 2 from the flight controller and plugged it into the receiver. We put the transmitter into bind mode and waited for it to sync with the receiver. Once this one done, the transmitter acknowledged the connection and we could power down the receiver.

The receiver has labels on the connectors. Looking from the bottom with the printing on the left, the bottom row is the bind/dat row. The next row is labeled Thro which correlated to channel 1. The Aile (aileron) is channel 2. The ELEV is channel 3. The RUDD is channel 4. The GEAR is channel 5. The AUX1 is channel 6. Once we map these to the receiver, we need to program the transmitter appropriately.

receiver

With the receiver connected, we power on the quadcopter by plugging in the battery (while connected to the laptop) and can calibrate the rc transmitter so that the controls min out at 1000 and max out at 2000. This is done for the four channels that represent thrust (THRO), pitch (elev), roll (aile), and yaw(rudd). By moving the controls on the transmitter we can see the controls change on the computer. The motors should also spin while you are playing with the controls. You should be able to verify the different motors spinning as you adjust the controls.

tx_cali2 tx_cali

At this point we have a transmitter that communicates to the receiver. We have a receiver that is communicating to the flight controller. We also have a flight controller that is energizing the speed controllers and making the motors spin. The only thing that we are missing is a cover to protect our electronics and propellers.

The cover that we are using is a cover printed by the instructor. The cover is ABS so it is easy to modify with drill holes and cut excess edges off. You can then tape or velcro the top to the quadcopter frame. The instructor puts his receiver taped to the top cover. We are going to put our receiver between the two decks with double sided tape attached to the bottom. You can operate without a cover but your electronics are exposed and hitting the ground could get moisture or dirt into your circuit board.

cover2 cover1

We will use a dremel tool to route out parts of the cover to allow it to fit on top of the assembly and fix it to the frame using velcro.

The props are put onto the motor shafts. The rings under the quadcopter are stabilizers for the propellers to keep them from vibrating. The ring goes onto the shaft first followed by the propeller then the metal washer and metal nut. The metal washer is a bridge to protect the plastic propeller and help keep the nut tight on the shaft. Use a wrench to tighten down the nuts before flying every time that you fly. During flight, half the nuts are trying to get tighter and the other half is trying to get looser.

prop1

 

With this we have flight! Plugging in the battery and powering on the transmitter allows us to fly our new quadcopter!

Now that we are at the end of the class, let’s review the overall cost. The class itself was $345. This cost covered about half of the cost of building a quadcopter. The overall cost to build this system from scratch is just over $700.

The up front costs for this class are:

  • $300 – rc controller
  • $43 – Lectron Pro 11.1 volt Lithium Ion Battery
  • $45 – Prophet Sport Li-Pro 35W Peak Battery Charger
  • $345 – class fee

total cost: $733

Included in the ($345) class you get

  • $4 – clear electrical tape
  • $2 – solder
  • $18 – apc composite 9×4.5 MR (2) and MPR (2) props
  • $6 – XT60 connectors
  • $13 – Diatone Innovations Q450 V3 quadcopter frame
  • $21 – Afro ESC 20A speed controller (4)
  • $3 – zip ties / velcro / double sided tape
  • $13 – non-adhesive shelf liner
  • $220 – Multistar 2213-980 14-pole outrunner motor (4 at $55 each)

total in parts: $300 that comes with the class

optional components are:

  • $20 – prop balancer
  • $8 – lipo battery monitor
  • $60 – watt meter

Overall, this was a very good class. It was good talking about the theory and practical ways of building a quadcopter. The class does not focus on flying but does talk about when, where, and how to fly. You are on your own to learn how to fly and repair the quadcopter as you crash while learning.

 

quadcopter assembly – part 2

In the last post we started by documenting a class that details how to build a quadcopter.

quadcopter

 

In this post we will look at the Diatone Innovations Q450 V3 platform ($13).

q450

The first step is to solder the power connector with the female connector to the board. We solder the red lead to the “+” and the black lead to the “-“. We also put some solder on the pads that will be used for the motor controllers. On the Q450 that we got there are eight pairs of connectors. We prepared the outer four “+” and “-” pads with solder to accept the motor connections.

q450_withPower

The next step is to attach the speed controller circuit (ESC) to the extension arm and solder the non motor connection leads to the board. The ESC is attached to the extension arm using zip ties. Nothing else needs to be done to attach it since it should stay in place and not slip during flight.

The ESC that we are using is the Afro ESC 20A ($21 each and we need four of them). The system has three types of connectors. One goes to power, one goes to the electronics, and one goes to the motor. In the picture below the red, yellow, black go to the motor. The black and red on the right are the power connections that we will solder to the Q450 board. The purple, red, yellow ribbon cable is the control cable that will be attached to the controller.

afro_esc2

 

We use a simple zip tie and a non-adhesive shelf liner (part of $13) to keep the ESC in place as shown in the photo. We then cut the power cables (right red and black cables in photo above) and solder them to the Q450 board (shown below).

arm_with_escesc_to_q450

Once we have the power cords soldered to the Q450 board we screw the arm onto the Q450 to relieve the cable strain on the newly soldered wires. The connection should look like the photo below.

arm2

The biggest difficulty that we had was the spacing between the mounting hole for the arm and the angle that the cables came in. At times the black wire covered the screw hole and we had to re-solder the wire to attach from a different angle.

Once we have the arms installed, the next step is to mount the motors and test the electrical. We are using the Multistar 2213-980 14-pole outrunner motor ($55 each, we need 4).

motor

Each motor is attached to the arm with four screws. When we initially tried fitting the screws through the arm a couple of them did not want to go through. The arms are injection molded and had a little “overhang” on the screw hole. Using an allen wrench we were able to clear the excess plastic and mount the motors on the arm.

 

 

and now for something completely different – building a quadcopter

Everything technical needs a diversion. This will be a log of building a quadcopter based on a class that I attended this weekend. The class is hosted by the Houston Hackerspace TxRxLabs. It is a two day class that results in a working quadcopter at the end of the class.

“Everything you need to know to start building your own multicopters. This is a hands-on class in which, by the end of the class, you will have built your own RC quadcopter.”

quadcopter

The pre-notes for the class can be found here. The most important thing to bring is a remote control unit similar to what is used for RC cars, boats, and planes. We purchased the Spektrum DX6 ($200-$300) from a local hobby shop in Houston. The majority of the class purchased the Taranis FrSky X9D ($300). The major benefit of the Taranis is that it is a 16-channel system rather than a 6-channel system for about the same price.

The instructor presentation is a good overview of the class.

The class started out with a discussion on where it is appropriate and not appropriate to fly drones. The best place to start flying is to fly on private property, local parks, or a certified flying field. There are places where you should not fly. www.airmap.io is a list of no fly zones. A good rule of thumb is nothing within 5 miles of an airport or over anything government facilities (state and local).
no_fly_zoneAlso keep in mind where you are flying and what would happen if you loose power. For example, don’t fly over a highway or places with large crowds. The quadcopter has weight and can travel upto 50 plus miles per hour.

www.meetup.com/sotexdug is a local drone flying club. www.rchouston.com is another local flying club but not specific to quadcopters. They rate and list local flying fields.

 One important thing to focus on is making sure that your propeller is not too heavy on one side. This will cause stress and instability and excess wear and tear on your motor. A prop balancer is a good investment ($20). Cheaper balancers are also available and can be used by hand ($6). It is important to get something that will work with a 9 inch prop. The props that we are using for this class are APC Composite 9×4.5 MRP props ($9 for two props).

To balance the prop you mount the prop on the balancer and watch which side drops to the floor. You can add weight to the top part of the prop using small clips of clear electrical tape ($4). propBalancer

In this example it took 3-4 small pieces of tape to get the prop to remain relatively level. It is important that the tape not get too close to the leading or trailing edge of the prop. The tape should also be placed on the inside edge of the prop and not on the outside edge. The inside edge is the edge where the air flow is at a minimum. This changes based on how you mount the prop on the motor and rotation direction of the prop. The tape is relatively strong and should stick.

tapeOnProp

The next discussion was around battery life, best practices, and recommendations. Try not to discharge the cell below 3 volts and don’t store them uncharged. Charge them before you put them away for the week. They will loose charge sitting in the bag and if you get below the minimum charge it will not retain as much charge in the future. We purchased the Lectron Pro 11.1 volt Lithium Ion Battery (2200mAh ($69 for three pack) and 3500mAh ($43 for one) batteries). You only need one but we got two so that we could extend the flight time.

A good tool to have is a lipo battery monitor that shows the quality of your battery ($8 for a pair). A good rule of thumb is to store the batteries in a cool location. An ammo can is a good place to store the batteries because bad batteries tend to do bad things (fire, explode, insert what you want here).

You will also need charger that is compatible with the battery that you purchase. We selected the Prophet Sport Li-Pro 35W Peak Li-Po Battery Charger ($30-$45). The charger has a 2S and 3S plug on the front. We will use the 3S connector because the batteries that we purchased are 3 cell batteries.

 Servos are something worth looking into. If you are going to mount a camera onto your quadcopter to help with navigation you will need to tilt your camera up when you go faster and level when you slow down. If you don’t tilt your camera it will be pointing into the ground and not in the direction of flight. Most servos operate at 4-6V DC. For a nav camera a small motor with a separate battery might be better. You don’t want to loose your vision or have vision draw too much current from the rotors.

The speed controller is what controls the rotation of the motors. They are driven by a pulse width modulation (PWM) signal from the remote controller. They work on 5V and typically draw 500mA but do generate a significant amount of heat if used over a long period of time.

When selecting a motor it is important to know the prop characteristics, the current draw, the rotational speed at nominal operations. There are a variety of motors that you can select as well as a variety of props. You can look at the wattage and current that is being consumed. A watt meter ($60) is a good tool to have to fine tune the prop and motor relationship. It is not necessary but good to have when designing a quadcopter.

When looking at a prop, it is important to make sure that all props are the same. Don’t mix and match props on the same quadcopter. When looking at a prop it has lettering and numbering on one side, a smaller hole and a bigger hole. The bigger hole faces the motor and the smaller hole with lettering is the outer edge of the prop. The numbers on the prop designate the size and pitch. In our case we have two 9×4.5 MR and two 9×4.5 MRP props. This is a 9 inch prop when measured from tip to tip. The 4.5 is the pitch of the prop. This combination designates the lifting power of the motor-prop combination. The P designation is for pusher and the non P designation is for pulling.

If you are designing your own new system a good rule of thumb is that the quadcopter should hover level at half throttle. Many prop manufacturers have charts that show thrust in grams with rotational speed and amps/wattage for different motor-prop combinations. You can hook up a rig with a kitchen scale to measure force as well as current draw when looking at changing the motor and prop selection.

We will be using the Acro Naze32 Flight controller board ($30) for this class. You can get an upgraded board with barometer and compass ($40) integrated to measure elevation and direction. You can hook up a GPS to this system as well to get absolute position and fly waypoints. The PWM channel decoder integrates to the RC Receiver (and transmitter) and translates the controls into PWM outputs that go to the speed controller for the motors. The Naze32 is designed to work with six motors but we will be using four in the class.

Naze32

 The first step in assembly is to prepare connectors for the batteries. We will be using the XT60 connector ($6 for five pairs) to bridge between the battery and controller. We use heat shrink tubing on the connector to keep from shorting while we are soldering. The resultant female side should look like the photo below.

 xt60-2 xt60-1

Make sure that you put the red into the “+” connector and the black into “-” to ensure polarity.

 The next step is to cut the old connector from the battery and put the XT60 male connector on the battery. Make sure that you cut one, and only one, side at a time. Cutting both leads will short out the battery and ruin your day as well as the cutters and battery. In the photos below we cut the red wire, soldered the new connector on, and applied the heat shrink tubing. This needs to be done to make sure that the soldering iron does not short out the negative lead while we are attaching the black wire.

 battery-1battery-2battery-3

At this point we have a battery with the XT60 male connector and a wire with an XT60 female connector.

Mounting local drive with guest extensions

In the last entry we created a Linux install by creating a new virtual machine and booting from an iso image. This works but is very time consuming every time we want a playground. In this entry we will clone an existing machines using thin cloning, modify the clone, add guest services extensions, mount the E:\ drive to reading, and stage an installation of the 11g Oracle database.

The first step is to clone our existing machine. We don’t want to create a new one because the first one took almost two hours. If we left click on the oel6u5 example and right click we can select Clone…

Screenshot 2015-07-02 17.36.32

 

We are given the option of a full clone or a linked clone. A full clone takes all of the files that we created (the 40G root disk which is thin provisioned) and makes a new copy of it. The linked clone tracks differences from the old instance and the clone instance. As changes are made to the new instance, they are recorded in a new directory. The old instance is forked and any new changes happen in a new file. The old file preserves a spot in time where the two were the same. Screenshot 2015-07-02 17.36.45

 

The linked clone comes back almost immediately since no files are copied to create the new instance.

Screenshot 2015-07-02 17.36.51

 

What we want to do is mount the E:\ drive as a media folder inside of our guest operating system. To do this we must go to the settings and select shared folders. We Add a shared folder access point and map it to the E:\ drive. We automount it and make it read-write.

Screenshot 2015-07-02 17.36.59 Screenshot 2015-07-02 17.37.10 Screenshot 2015-07-02 17.37.18

 

While we are in the setting we also need to remote the CD/DVD since we are finished installing the operating system and want to boot off our new instance. We do this by selecting Storage, selecting iso file that we mapped, and clicking on the blue icon at the bottom with a minus sign in it. This removes the CD from our mapping and we boot from the hard drive that we used for our installation.

Screenshot 2015-07-02 17.37.51 Screenshot 2015-07-02 17.40.30 Screenshot 2015-07-02 17.40.33

Once we reboot, we log in as the user oracle and add the guest services extensions. This is done by going to the top menu bar in the VirtualBox window and selecting Insert Guest Additions CD image from the Devices menu. This mounts the CD and asks you if you want auto-run the content.

Screenshot 2015-07-02 17.41.00 Screenshot 2015-07-02 17.41.50 Screenshot 2015-07-02 17.42.05 Screenshot 2015-07-02 17.42.15 Screenshot 2015-07-02 17.42.23 Screenshot 2015-07-02 17.43.13

Note that kernel modifications were made to map the local drive to a mounted resource. We can eject the guest services CD and verify that the file system is mounted.

Screenshot 2015-07-02 17.43.27 Screenshot 2015-07-02 17.43.49

It is important to note that the /media/sf_E_DRIVE is readable only by root. We can copy data from this location to a local location as is needed for database installation or just access the data as root.

Screenshot 2015-07-02 17.44.16 Screenshot 2015-07-02 17.45.58

Before we install the 11g database we will want to change the hostname of this machine. We will keep the ip address the same but change the hostname by editing the /etc/hosts and /etc/sysconfig/network files. We will also need to change ownership of the staging directory back to oracle with the chmod -R command to make it owned by oracle for the installation.

Screenshot 2015-07-02 17.49.42 Screenshot 2015-07-02 17.50.13 Screenshot 2015-07-02 17.51.12 Screenshot 2015-07-02 17.52.13

In this example we change the hostname from oel6u5ex to db11g since we are staging to install the 11g instance of the database. We could have changed it to db12c if we were going to stage the 12c instance of the database. The process and procedure is the same with the exception of the hostnames and which database binaries we put into the staging area.

up next: installing the 11g database into our sandbox

Installing OEL6U6

In our previous post we downloaded VirtualBox, downloaded V41362-01.iso, and configured a single core, 4G of RAM, 40G of hard drive system with two network interfaces. We mounted the Oracle Enterprise Linux Release 6 Update 5 as a virtual CD-ROM once it finished downloading from edelivery.oracle.com. We stored on our E:\iso directory on our sandbox system to use again if needed. We created the virtual disk in the E:\VirtualBox VMs directory and are ready to boot the operating system to start the installation process.

To be honest, I reverted back to OEL6U5 because I had trouble getting the OEM6U6 to install and configure properly. I went with something that I know works and the features/differences between update 5 and update 6 are not that significant when it comes to the Oracle database.

To start the installation process we select an iso image by clicking on Storage and selecting the CD/DVD iso that we are going to boot from. In this case we select the V41362-01.iso file from our E:\iso directory and click on the green Start button at the top left.

Screenshot 2015-07-02 16.04.47Screenshot 2015-07-02 16.06.27 Screenshot 2015-07-02 16.04.25  Screenshot 2015-07-02 16.06.44

 

Once we click on start it takes us to the boot menu for the operating system. We select install and follow the menu prompts.

Screenshot 2015-07-02 16.06.58Screenshot 2015-07-02 16.07.26Screenshot 2015-07-02 16.07.31Screenshot 2015-07-02 15.33.28

Screenshot 2015-07-02 16.07.54 Screenshot 2015-07-02 16.07.59 Screenshot 2015-07-02 16.08.03 Screenshot 2015-07-02 16.08.08 Screenshot 2015-07-02 16.08.27

Configure the network so that eth0 has a static ip address of 192.168.1.121, netmask 255.255.255.0, and default router is 192.168.1.254 (this is my Uverse router). The default dns is 8.8.8.8 with the backup being 8.8.4.4.

Screenshot 2015-07-02 16.08.36 Screenshot 2015-07-02 16.08.44 Screenshot 2015-07-02 16.09.17 Screenshot 2015-07-02 16.09.31 Screenshot 2015-07-02 16.09.45 Screenshot 2015-07-02 16.09.55

 

after setting the timezone and root password, choose to overwrite all data on the existing disks and select a software development platform to install. The software development platform is selected to give us a compiler as well as a user interface. If you select the basic server you do not get a user interface.

Screenshot 2015-07-02 16.10.07

Screenshot 2015-07-02 16.10.17 Screenshot 2015-07-02 16.10.24

Screenshot 2015-07-02 16.10.31 Screenshot 2015-07-02 16.10.39 Screenshot 2015-07-02 16.10.47 Screenshot 2015-07-02 16.11.12

Once the system comes back you can reboot and finish the installation.

Screenshot 2015-07-02 16.24.26Screenshot 2015-07-02 16.25.33   Screenshot 2015-07-02 16.26.03Screenshot 2015-07-02 16.25.48Screenshot 2015-07-02 16.25.57Screenshot 2015-07-02 16.25.43Screenshot 2015-07-02 16.26.17Screenshot 2015-07-02 16.26.29Screenshot 2015-07-02 16.26.37     Screenshot 2015-07-02 16.26.46

At this point we have a valid system and can login, alter the /etc/hosts table, alter the /etc/sudoers file, and run yum update to download the latest patches.

Screenshot 2015-07-02 16.40.52 Screenshot 2015-07-02 16.41.05Screenshot 2015-07-02 16.41.28  Screenshot 2015-07-02 16.41.53Screenshot 2015-07-02 16.43.09Screenshot 2015-07-02 16.43.42   Screenshot 2015-07-02 16.46.18

The yum update will probably take as long as the installation process took. Overall this takes about an hour or two depending upon your network connection speed and amount of RAM that you allocate.

Screenshot 2015-07-02 17.32.54

We now have a fresh install of Oracle Enterprise Linux 6 Update 5 with the latest patches. I suggest that you clone this instance and put it on long term storage somewhere. We don’t need to spend an hour or two recreating this again.

up next: Mounting the E: drive inside the virtual machine to stage other software installations.

 

Downloading and setting up installing OEL6

In this entry we will go through downloading and installing Oracle Enterprise Linux Release 6 update 6. We are selecting this version over RedHat or Ubuntu or Debian because most of the Oracle documentation talk about how to install and configure on OEL6. We could do this for OEL7U1 or OEL5U?. We just selected OEL6U6 because it is the most recent with the best examples on the web.

Two things to consider when installing guest operating systems on VirtualBox are iso images and image sizes. To make things easier we consolidated software into two directories. The first is an iso directory. This directory is for operating system installations. The second directory is for the binaries like the database or identity servers. It is easier to isolate the two because one is used to jumpstart a new instance. The second directory can be mounted and pulled into an instance to install software. The second are that we need to consider is the directory to hold the virtual images that VirtualBox creates.

For our sandbox machine, we installed a 2T disk to hold iso images, binaries, and virtual images. In our example, this is drive E.

Screenshot 2015-07-02 14.04.00

We have consumed about 500G of a 2T drive

Screenshot 2015-07-02 14.03.47

There are three directories that we created: iso, oracle, and VirtualBox VMs. What we want to do is download the operating system iso files from edelivery.oracle.com and put it in the iso directory as is shown.

Screenshot 2015-07-02 13.59.21

To keep things a little more organized, we use a naming convention to identify the iso file. Oracle creates a file with a filename like V52218-01. This means nothing to me but OEL6U6 x86_64.iso has relavance. Note the file convention that we use contains both. The V(number).iso tells us the version that was downloaded from the edelivery site and the OEL6U6 tells us that this is the Linux Release 6 Update 6 version of the OS. Note that some of the conventions are reversed. For the OEL7 iso we had the V(number) inside the parenthesis and the OEL7 outside. Either works as long as you can tell which is which easily.

To download the iso file, you need to go to edelivery.oracle.com and select the Oracle/Linux VM from the top of the screen. There are three options in the pull down: Main, Oracle/Linux VM, and Oracle 1-click. The Main and Oracle 1-click allows you to download the installation binaries for things like the database or E-Business suite. The Oracle/Linux VM allows you to download OracleVM, Linux, and Solaris binaries. Unfortunately, the license requirements and conditions are different prior to downloading the software. Oracle requires you to select what you are going to download and agree to user and license restrictions.

goto http://edelivery.oracle.com and select Oracle Linux/VM to get to the operating system download.  Screenshot 2015-07-02 13.56.16Screenshot 2015-07-02 13.56.20

 

 

 

 

 

Login with your oracle.com credentials.

 

Screenshot 2015-07-02 13.56.31Screenshot 2015-07-02 13.56.40

 

Accept the license to search for the OS

Screenshot 2015-07-02 13.56.52

 

 

 

 

 

 

 

 

 

Look for Linux on a 64-bit systemScreenshot 2015-07-02 13.56.59

 

 

 

 

 

 

 

The OS downloads will come back in release order. Re-sort by Updated date to look for the latest version. Screenshot 2015-07-02 13.57.12 Screenshot 2015-07-02 13.57.19

Select the Release 6 Update 6 version and download the iso images. Note that there are three. The largest is the DVD image that we typically want to boot from.

Screenshot 2015-07-02 13.57.36  Screenshot 2015-07-02 13.57.53

The download takes a while. Remember that you are downloading a 4G iso image. There is no need to download the source, only the bootable iso image.

Once the images are downloaded we need to configure VirtualBox to read this image and boot from it. To start this, we click on the New icon at the top left of the VirtualBox console.

Screenshot 2015-07-02 14.34.35 We call this instance OEL6 example, select Linux as the OS and Oracle 64-bit as the version.  Screenshot 2015-07-02 14.34.50

 

 

We change the memory for this instance to 4G. We can get by with much less but if we are using this for a database, 4G is the minimum recommended.

We create a 40G drive as a virtual, dynamically created drive. Note that we could create this as a VMDK file which makes it compatible with VMWare. In our example we use the VDI since is compatible with OracleVM. Either should work.

Screenshot 2015-07-02 14.34.55 Screenshot 2015-07-02 14.34.59 Screenshot 2015-07-02 14.35.03 Screenshot 2015-07-02 14.35.23

 

We now have a virtual container that we can boot an iso image into. We do need to modify the network as well as mount the iso image as a CD-ROM for booting.

Screenshot 2015-07-02 14.36.58

To map the iso image, we click on the storage and map the iso image as a CD-ROM. Click on the Circle on the right with a Plus sign on it. This pops up the add new CD/DVD question and file selector when we click on Choose disk.

Screenshot 2015-07-02 14.43.17 Screenshot 2015-07-02 14.43.22 Screenshot 2015-07-02 14.43.30 Screenshot 2015-07-02 14.43.35

 

Next we configure the network to have a bridged interface on adapter 1 as well as a host only network interface on adapter 2. This should give us an eth0 as a bridged network and eth1 as a host only interface.

Screenshot 2015-07-02 14.43.45 Screenshot 2015-07-02 14.43.54

From here we click on Start at the top left of the VirtualBox console which gets us into installing the operating system.

Up next: Installing OEL6U6

 

Installing VirtualBox

VirtualBox is a virtualization software package that allows us to create a sandbox to play with Oracle software. We initially selected a deskside computer that is capable of hosting a variety of virtual guests. Our system has 24G of memory and a quad core Intel i7 processor. On Windows you can go to the Control Panel -> Systems to look at the memory and processor configuration.

system config

To download the software you can go to the VirtualBox web page and download the binary for the OS that you are running. In our example, we download the Windows host x86/amd64 binary.

virtualbox.org

From this, you can execute the binary and install the software. There really is not many options other than where you can install the binaries and if you want a shortcut on your desktop and startup menu for Windows.

Windows screen shots

MacOSX screen shots

The user documentation for VirtualBox is relatively helpful if you get stuck. Chapter 2 covers the installation on the various operating systems. Chapter 4 covers guest additions. If you want to mount a directory from your desktop computer you will need the guest additions. Chapter 6 covers networking. For most of what we will focus on, three network configurations are worth learning in more detail.

  1. bridged networks
  2. host-only networks
  3. network address translations

Bridged networks allows you to use DHCP or static ip mappings and send/receive data across routers. In my instance I use bridged routing to connect through my AT&T Uverse router and can see the virtual instance from outside my house. Bridged networks are needed for this so that the ip address is routable.

Host-only networks are good for virtual machine to virtual machine communications. If I have a WebLogic server configured to communicate with a database, I can use the host-only network which is non-routable and create a communications channel that is similar to a corporate backbone inside a DMZ. I can use non-secure communication mechanisms that are not available on a public network or can use things like remote desktop, VNC, or remote X-11 windows to display back to my MacBook Pro or Windows desktop.

Network Address Translation (NAT) is similar to bridged networks but keeps the ip address of the guest operating system hidden and not exposed. The VirtualBox engine and host operating system act as a router for the guest OS. I found that this works but makes administration a little more complex and less secure for my desktop OS if we want to route public ip traffic through AT&T Uverse into my guest OS. If we were trying to expose multiple guest virtual machines I would use NAT.

For our configuration we wanted to expose Enterprise Manager as the main console/browser into our network. We configure the AT&T router to map the DHCP address assigned to connect to the internet to map to the static ip address of the enterprise manager guest OS. In our instance that will be 192.168.1.120. This is a simple mapping that can be done on the admin page of the router using the firewall mapping. Any ports opened from the outside world to the router will get mapped to the static ip address. This allows us to server port 7802 which is the enterprise manager console port for demos. Security must be maintained on the virtual machine because all ports are now exposed to the internet and all script kiddies and hackers.

Screenshot 2015-07-02 13.30.48Once everything is installed you should be able to launch the VirtualBox management console and configure new guest operating systems.

Screenshot 2015-07-02 13.34.49

Note that this is a relatively mature installation with a variety of operating systems and configurations already done.

Up next: Installing Oracle Enterprise Linux and mounting local drives in VirtualBox.