Background

After replacing the motors on my tiny6, yet still having it feel sluggish after about a minute or two of flight time, I figured it was time to build a brushless whoop. I was also looking for a build with some challenging soldering in order to make use of the TS100 soldering iron. This one definitely fit the bill.

I've never been a fan of the oddly shaped whoop canopies, so I opted for a 'squashed' build. The flat form-factor is also nice as it seems less likely to get stuck. Easy to fly out from underneath a couch or bookcase whereas a regular whoop would be trapped.

I also recently got a relatively cheap security camera and was impressed with the night vision quality.. it works even in pitch darkness given only a few IR leds. Wouldn't it be cool to have a whoop that could also fly around in the dark?

And thus, the nightvision brushless whoop was born.

Build

The build is relatively straightforward due to how well the betafpv frame fits together and the all-in-one FC+ESC. Unfortunately I didn't take pictures throughout the process. I detached the camera/vtx AIO and sandwiched the vtx between the RX and the FC. The frame is actually backwards so that I had a flat surface to mount (glue) the camera to.

IR LEDs are mounted on both sides of the camera. It is important for them not to stick out past the camera lens or you will get glare. I also scratched up the LED surface slightly to create more of a diffused light rather than spotlight. Make sure to remove the IR filter from the camera as well. It is the pinkish looking small square usually mounted (glued) on the inside of the lens itself. It can be removed, with varying amounts of difficulty depending on how much glue there is.

The LEDs are wired in series with a 75 ohm resistor. It's hard to see because it is a surface mount resistor, so nice and small.

Switchable IR LEDs

Originally I was driving the LEDs directly from the battery, but that's no fun because then you can't switch them on & off. A straightforward solution to this would be to use the awesome betaflight LED strip functionality. A few problems with this:

1. The BetaFPV board doesn't have an LED pin. (However this can be solved by changing the betaflight resource assignments and repurposing a different unused PIN.. like buzzer).
2. They don't make WS2811 LED strips with IR LEDs (all of them are RGB). Most have the control logic built into the LED which is cool, but make it very hard to swap in an IR LED.
3. There are WS2811 controllers only but there isn't really room for an additional microchip in this build.

Instead, I opted to patch betaflight. Betaflight already has the concept of single LEDs (each directly controlled by a single pin rather than via WS2811). These correspond to built-in board status LEDs on most FCs. I patched betaflight to define an additional status LED, and mapped that to turn on/off with the existing LEDLOW status signal. Mapped that resource to the buzzer pin, wired up that PIN to the IR LEDs, and was plesantly surprised when it worked flawlessly. Leave a comment if you are interested in the patch.

The result is IR LEDs that are controllable via the transmitter.

Flight Video