Build Snapdragon Flight Drone

In order to have a VR Drone, we must start building a real physical Drone. Snapdragon Flight offers a great light weight powerful platform we can do a lot with. While most home built Drones are built with very custom specs; I felt it necessary to make this very approachable by ensuring the Drone is built exactly as the specs outline.

Our's looks slightly different, but hey Drone time!

Let's start with the parts the Drone needs:

• Allen Wrench Hex Key Set
• Dynamite 5 pc Metric Nut Driver Assortment
• Generic M2.5 Nylon Hex M-F Spacer/Screw/Nut Assorted Kit
• Loctite Heavy Duty Threadlocker
• 2x clock wise motors
• 2x counter clock wise motors
• ac converter for battery charger
• battery charger
• Battery
• ESC (to control the 4 props)
• Frame Kit
• gps antenna
• 4 x DF3-3P-2DSA connector
• Wifi antenna
• Grey props: x2
• Red props: x2

Before jumping straight into working with the hardware, a small house keeping task must be preformed. There's a small problem, If you have big hands like me, you will have problems attaching the Serial Debug Board + cable to the drone when it's all put together. So before making a labyrinth for your hands to navigate, let's first power up the board, and tell it how to accept access to it by WiFi. In this way, we can log in as root after putting everything together.

With the Serial Debug Board/cable attached, and the Snapdragon Flight given power, you should see a blue LED light on the flight light up. Now you can communicate with it over Serial USB. To do that, varies by Operating System. Check out the blog post on how to connect to a serial link.
Once connected, I'd suggest setting up WiFi on the device. First, let's get AP mode enabled and setup:
/usr/local/qr-linux/wificonfig.sh -s softap
Reboot the device with: reboot.
Edit the file /etc/hostapd.conf, as you are logged in as root, there's no need to use sudo. You're going to want to enable either 2.4 gighrz mode or 5 gighrz mode by uncommenting the lines that denote it. NB that all wifi devices will work over 2.4, while some might not work over 5; choose well. Set the SSID to be something you'll remember, I set mine to VRDrone. Then set the password to something you'll remember.
While still connected, let's change the root password with the passwd command. Why would we want someone else to have the ability to hyjack our drone potentially? Also, su to the linaro user and change that password as well; linaro's default password is... linaro so definitely change that.
When finished configuring that file, reboot the device, with a reboot command. When it comes back, you can check if your configuration worked by using ifconfig wlan0. Inet Address should now be 192.168.1.1 which is the default gateway. NB, you should now be able to connect to this new wireless network from any WiFi enabled device just as you normally would connect to a new network.
I find it convenient to also tell Flight about the local network so it will have internet access. In the current configuration, if you connect to it over wifi than both your computer and flight will not have internet access; as I highly recommend updating all software on flight with apt-get, it's probably best to configure both flight and your host machine to use your local WiFi network. To do that, we're going to reboot into station mode with:
/usr/local/qr-linux/wificonfig.sh -s station
Reboot the device with: reboot.
Edit the file /etc/wpa_supplicant/wpa_supplicant.conf, Setup the configuration file to reflect connection information on your network. This is fairly straight forward, if you need to connect without security (not recommended setup), then set key_mgmt=NONE. If not, then set all fields to correct values. If you need information on supplicant, if you have a unique situation, check here. Now just reboot the device and let's check how we did:
ifconfig wlan0
You should see Inet Address set to an IP that looks like it's on your network. You should now try connecting to it over SSH with ssh linaro@. If you can log in without issue, and can get to root without issue, then you're safe to remove the serial debug board and continue on to the hardware with me.

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1.) The first step in the instructions as of version 1.6 is to place spacers on the top of the flight for the three holes that wouldn't interfere with having the serial USB board attached. Wouldn't want to make it hard to use the board later, so we shall heed the sage advice. However, there's one modification to their plan. Unfortunately the instructions call for 3x standoffs (male-female, #2-56 thread size, 3⁄4” height) o Nylon standoff is preferred to avoid shorts. However, there are no Nylon standoffs that fit those size specs and the aluminum varient of that same dimension actually doesn't fit the screw size that comes with Snapdragon Flight. Thus, I recommend switching to using nylon 2.5mm threaded spacers. You'll note that I called out an assortment box in the list above. Any of the spacers in that box will fit, I'd pick the 3-4" height ones to keep as close to the recommendations as possible and provide room for the Serial Debug Board if you choose to attach it in the future.
Here you'll see me complete the first step:

2.) Next we attach the four legs to their proper places. Ensure that the plastic is on the bottom of the plate (helps to know which side is up). Then attach the legs such that the wing nuts are towards the inside of the body of the craft and on the top.

3.) Next step is to figure out where to drill holes for the spacers to attach the Snapdragon Flight to.

4.) After drilling the holes for the spacers, go ahead and attach Snapdragon Flight.

5.) Attach the landing skis to the bottom plate, ensure that the skis are facing forward.

6.) Attach the 4 spacers to the bottom plate.  These act as the middle layer and give structure to the body when the legs are spread out in flight mode.

7.) Attach the top plate to all the middle layer screws.

8.) Install the Electric Speed Control (ESC) to the top of the top plate, you'll need to drill two new holes for the back of the ESC.  The ESC handles translating the commands from flight into what speed to run the motors at so they perform the flight as intended.

9.) Attach the motors and props.  Please notice that unfortunately the connector on the motors doesn't fit the connector on the ESC.  So in a coming step, we're going to change the connector out for a DF3 connector.  This three prong connector will fit the ESC perfectly.  This will require soldering, and as the ESC is the expensive part, we'll work on one motor at a time, for now, place everything where it will go, and we'll tackle the connector change later.

10.) The final step for now is to push the battery into place.  It sits very snugly in the middle layer.  Please ensure that any tears in the wires are patched with electric tape, and the charging wires and power wires are accessible.

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As soldering is a very useful skill especially when it comes to electronics. I'm going to end this blog post here. The drone is mostly complete, only missing the ability to attach the motors to the ESC. I'll pick up another blog post to cover soldering in proper detail and use it to show how to finish this project from the hardware perspective. Till next time!