I recently received a $50 Amazon gift card and decided to use it to buy components for a new micro brushed FPV rig. I found an interesting flight controller which seems to be fairly new. It is based on the STM32F303 micro. It only had two reviews and I could not find much information about it. There were two features that I found interesting, so I decided to give it a try. First, it has an integrated FrSky compatible RX. Second, it has integrated OSD. This is the HobbyMate AIO F3 (https://www.amazon.com/gp/product/B06XRZ7LVJ/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1).
I also found an interesting camera/VTX combo that has decent specs and fairly good reviews. This is the Wolfwhoop WT05 (https://www.amazon.com/gp/product/B06XJMQQ6Y/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1). It has a 25mW VTX and is only 15x12x7mm (not including the lens), and weighs only 3.4g. I decided to give it a try.
The reason for this post is to share what I found that might help anyone wanting to mod one of these little AIO camera/VTX modules to work with OSD. Since the camera module is soldered to the VTX module, the video signal is not easily routed to the OSD. On this particular module, the signal lines were not labeled. On visual inspection, there were six header pins around the corners of the modules which connected the camera and VTX boards. Two were obvious, as they were directly connected to the power lead. Using a multimeter in continuity mode, I was able to determine that the single pin header was ground, as was the center pin in the three pin header. That left two pins which could possibly be the video signal - one of the two end pins on the three pin header. I powered up the VTX and put an o’scope probe on each of the candidates and was able to determine which one I was after.
I didn’t think to take a picture before I began the mod. This is one of the listing images from Amazon showing the three pin header:
The pin on the bottom is the video signal. I used a small pair of diagonal cutters to clip out the video signal header pin from between the boards. This is what it looks like with the pin removed:
From here, it is just a matter of soldering leads for the Vin (video in) and Vout (video out) on the OSD:
The pin circled red goes to the Vin and the green one goes to Vout. Here is the final mod:
I wired the other side to the OSD pads on the FC board like so:
From there, all that was left was to fire up CleanFlight and configure the OSD. The config that came on the board already had the OSD enabled and mostly configured. I tweaked a couple of settings, saved it and broke out the goggles. The camera has a decent image and the OSD is working as expected.
I have almost finished with the build, but it is not ready to fly yet. Binding the the TX went well, and everything looks good so far. It arms and the motors spin up. It seems that I mounted two of the micro JST connectors for the motors backward though, so I won’t be able to test it out until that is resolved.
If anyone is interested in this FC and VTX, let me know. If so, I can post again with results of my flight test (VTX range, FC performance and whatnot).
Here are a couple pictures of the build thus far: