Building the drone - part2

A project log for Flying Sniffer

Sensors mounted on a drone connected to a robust data infrastructure, for pollution monitoring, wild fire prevention and CBRN defense.

Radu MotisanRadu Motisan 07/16/2017 at 17:100 Comments

So many things to do, but so little time. I went for a 2200mAh battery I found in the local market (just an aliexpress import sold at twice the price, but hey, I needed it fast).

To assemble the drone, I soldered the Power distribution board on the bottom - and the 20A ESCs on the arms, the cables were just right:

The 3 ESC output wires were removed, and the motor wires soldered directly. This would reduce some of the unneeded resistance of the longer wires, but also allow for a more compact assembly. For a first test, I went for the NAZE32 flight controller board, and connected it to CleanFlight software in Chrome.

I was able to install the USB drivers, and then flash the newest firmware to the NAZE32 through CleanFlight. The sensors were accessible, I was able to see the accelerometer, magnetometer, barometer all working.

The GPS, a mini NZ GPS didn't want to function. I wasn't able to get the ESCs to fire, and neither the R9DS receiver.

The #Flying Sniffer is taking shape, but it seems so far from its goal right now. Before I can do the environmental monitoring work I need a proper flying platform, reliable, stable and with telemetry working, so I can do sensor readings and map the location, at leas this:

As a backup plan I changed the NAZE32 for the SPRACING F3 with integrated OSD flight controller. I went the same route, using CleanFlight to program the board. I tested the R9DS and one ESC together and it worked.

I found the mistake in my settings, and was able to get the ESCs going. Same for the R9DS, using it via the SBUS:

Same for GPS, but I didn't use the NZ GPS, instead I went for an UART NEO6M module with a bigger ceramic antenna (plenty of them on aliexpress, and much cheaper than the NZ GPS). I used these a lot in my #Portable environmental monitor, so it was easier for me. Baudrate was 9600bps by default and communication via the NMEA protocol:

With the remote and the motors working, and a 2200mAh battery it appears I have all I need for a first test. But the motors would not engage at the same time. I found a youtube tutorial to "calibrate" that, and also learned that the Flight controller must be correctly installed at the top of the quadcopter. Made things better.

First flight

I found a safe place to try this. My first daughter (2Yrs 2M) loves drones already, she saw a filming one at the christening of her little sister, so before I master the drone I built I need to make sure no accidents can happen.

On a place with some grass, that would help with an eventual crash landing, I engaged the motors and wooosh! propellers blew in open air, getting dismantled from the drone, and the drone fell to ground. Apparently, even if the rotation matched the propellers and air was getting pushed down, the sense of rotation was wrong. That made the screws holding the propellers in place unscrew in an instant. I found 3 of them, but it was impossible to find the forth, even by using some very advanced DIY metal detection techniques:

I was able to find all the nails in the ground, but not the missing propeller cap screw. I changed the motor polarity, switched the propellers and secured the one with the missing screw with nylon wire. I was finally able to make the quadcopter fly, but only for seconds and it would drift very fast out of my control.

I suspect I need to calibrate the accelerometer.