The FPV conversion continues. After finishing the ground station, I’ve been adding camera and transmitter gear to the tricopter and quadcopter. The tricopter is, in theory, ready, but I’ve not had a chance to test it as the weather continues to be rubbish, so I’ve been playing with micro FPV gear for the quadcopter instead.
I originally tried converting a micro security camera into an FPV camera, but rather embarrassingly let the blue smoke out as I was attacking it with a soldering iron, so opted for a simpler dedicated FPV camera and transmitter instead. I soldered them directly to the LiPo plug in the first instance, but although I got a decent picture when the quadcopter was off, I got a lot of interference from the motors as soon as I armed it (I’m using a single LiPo to power both). I solved that with the use of a Pololu 5V switching regulator, and now get crystal clear video even at full throttle. The whole FPV setup, including regulator, weighs 4g. I’ve also added a Walkera-style plug so that I can run the quad off of Hubsan X4 compatible batteries, which are not only cheap and readily available, but much more responsive that the stock cells; the higher C rating really improves the throttle response.
To make room for the video gubbins on the top of the quad, I moved the DSM2 receiver to the bottom. I desoldered the cable plugs and instead soldered the Rx directly to the board, saving a little over a gram in weight. I also added landing gear in the form of zip ties. They’re light (0.1g per leg) and flexible, and since I’ve wrapped the motor wire out of the way around the arms, they provide good protection for all the components.
All in all, it flies really well. I’ve only added about 3g in weight from stock and only lost about 20s from my flight times as a result, but ended up with a much more responsive craft WITH FPV! It’s serious fun to fly, even if it is a bit tricky as the camera has a narrow FoV. I might swap the lens for a wider angled one in the future, depending on how much better I (don’t) get with practice.
I was happily flying around, when one of the motors decided to embark on an ill-advised solo career as a helicopter. The rest of the band didn’t fare so well without it, and, like this analogy, flailed clumsily before crashing to the ground.
Fortunately I managed to retrieve the escaped motor, and the tricopter crashed into some nice soft mud, so no damage was done, though I did have to spend quite a bit of time cleaning everything.
I was playing about with the Self Level mix mode of the KK2 1.6++ firmware, but due to user error, managed to get it to self-level upside down, 60 metres above the ground, which it then proceeded to slam into. Oops.
The tricopter held up surprisingly well considering the height and speed of impact, and the zip ties did their thing and let the motors break away cleanly, but there is still some damage to see to (cracked body, cracked receiver antenna, broken ESC cable). Time to get the tools out again.
The camera did NOT enjoy the crash – I had to recover, then repair the video file from the SD card, and sadly this is all the footage that there is.
The picture wire seems to have mostly cured the rolling shutter effect, but looking at the raw footage, I’m still getting shake.
Back to the drawing board.
This is one of the first videos I shot using the Mobius ActionCam on my tricopter, using my Super Simple Gimbal. It’s shot at 1080p/30fps, and I’ve not done any post processing on this video – I wanted to get a feel for the amount of vibration/rolling shutter distortion I’d get off the bat, in order to work out what tuning/redesigning I might need to do.
The gimbal is currently attached to a carbon fibre plate suspended from the tricopter using RC fuel tube with very stiff coat hanger wire inside. I’m planning to use larger loops of more flexible wire (picture hanging wire) next, to see if I can get rid of some of the shake. In both cases, the battery is attached to the plate, rather than the tricopter frame. I’ll post a comparison video of a similar flight one I’ve had a chance to test the new damping system.
Mobius information: www.rcgroups.com/forums/showthread.php?t=1904559
SSG instructions are here: www.rcgroups.com/forums/showthread.php?t=1793759
Testing out my self-built tricopter on the Enfield Playing Fields. I’d never flown *anything* before this, and it kind of shows.