Light Weight RC FPV for Quadcopter and other Multicopters
We copter hobbyists love RC FPV flying, and we have seen a lot of awesome FPV videos taken by professional and relatively large multi-copters. But It doesn’t have to be a big quadcopter or RC plane to do FPV. I recently looked into a cheap and light weight FPV solution, and I found a couple of options, which I will be making it happen in this post.
I know someone might have already done something similar before, but there might be something unique in my idea that could be useful to you.
The compact FPV system I have built is only about 20g, now even my mini quadcopter and micro hexacopter can carry this FPV camera and video transmitter. In this post I will share with you what are the parts you will need and how I made it.
UPDATE: I re-build this DIY micro FPV combo here, lighter, smaller, and better
Parts I am using for FPV
At the transmitter side, I tried to use the parts the are the lightest I can find. The 5.8GHz transmitter I am using is the TX5823 which is only 10 gram, and the Camera is MC495A which is 5 gram. So in theory you should be able to build the whole thing under 20 gram!
Both components requires 3.3V – 5V (description on eBay), that’s perfect to power this system from a ESC BEC or a seperate 3.3V Lipo battery. But from the official datasheet for the TX5823, it says it needs 3.3V input, so I am a little concerned. I decided adding a diode to lower the voltage a little just in case. The TX5823 working current is about 150mA and the camera’s working current is about 70mA, so a 1S 360mah Lipo should be able to power this for just under an hour (Tested, around 50 mins).
The TX5823 has 8 channels available controlled by 3 pins. The channels are all on E band. If you are not sure what E band is, check out the different FPV 5.8GHz Frequency Bands.
The receiver I am using is a cheap Chinese RC305 Receiver, it’s got 8 channels and it’s working fine. It’s working current is about 150mA. The monitor I am using is a 7inch LCD display from China. The working current is about 660mA (8W power under 12V). So for a 3S 2200mah Lipo should be able to power the ground station for around 2 and a half hours.
- TX: TX5823 (£10)
- Camera: MC495A (£21)
- Power for TX + Camera: 1S 360mah Lipo (£2)
- RX: RC305 (£25)
- Monitor: 7 inch LCD (£25)
- Power for RX + Monitor: 3S 2200mah Lipo(£5)
Circuit Designing, Building and Testing
I really enjoy designing and building the circuits on the board. It wasn’t straight forward and I got a lot of short circuits when soldering on the vero board. It took me a lot of time trouble shooting and checking the connections using the multi-meter.
In the original design I had quite a few ideas, like adding an LED to indicate power connection, adding a on/off switch, adding multiple voltage inputs for different voltage level (3.3V, 5V, 7.4V) along with voltage regulators etc… And the weight go all the way up because of the extra functionality. So at the end I decided to only keep the LED and remove all other stuff.
I soldered header pins on the transmitter to make it removable from the vero board, that’ also make it really easy for troubleshooting.
Circuit is quite simple. I added two capacitors for the transmitter to filter out noise, it really improves the quality of the video transmission.
Before soldering, I tested the circuit on a breadboard, checking voltage and current are correct. One thing I notice is, when using the diode, DO NOT just use 0.7V as the forward voltage, it changes with forward current. Check datasheet or test it yourself, for 1N4001 I am using, at 230mA the forward voltage is about 0.9V.
I will still need to put an cloverleaf antenna on it, which should increase the range a lot. Without an antenna (Yes, no anntena at the moment), the range is already about 10 meters.
I have yet tested this outdoor, I will probably practice FPV flying first.
Finishing with the FPV cloverleaf Antenna
Finally the RP-SMA male connector and the cloverleaf Antenna have arrived and I soldered them on the board. I also made a little adjustments on how I mount them on the mini quadcopter.
You can also make your own Antenna.