FX798T Combo Mini-camera/VTX - DIY Tiny-Whoop using JJRC H8 Mini
Post date: Sep 19, 2016 11:17:43 PM
Some of you may have seen FliteTest post a video showing how to use a Blade Inductrix and a tiny combo camera/VTX (Video Transmitter) to build a tiny FPV (First-Person Video) platform that you can use indoors. The Inductrix sells for as much as $80 at various stores online, and FliteTest sells the cam/VTX they used for $55. That's a bit outside of my budget for a toy like this. Especially considering you can buy RTF (Ready-To-Fly) non-toy-grade FPV quads for about the same money. Plus the Inductrix is kinda slow and not very nimble.
Meanwhile, JJRC makes a tiny quadcopter called the H8 Mini that sells for anywhere between $12 and $25 depending on where you look, and it's a blast to fly, both indoors and out. The controller has 2 rate modes: "Insane/Unflyable", and "Crazy Fast". Yeah, those are my names for the different rate modes, not what they call it in the manual. JJRC recently released another micro-quad called the H36 Small Spirit. And gee, it looks an AWFUL lot like the Blade Inductrix... Except for the price tag: $20! I bet it's just as quick and maneuverable as the H8 mini.
TMart contacted me and asked if I could make a demo showing how to install their $40 FX798T-L miniature camera/VTX combo to an H8 Mini. This unit is a tiny 600TVL camera with a 25mW 40 channel (including Raceband) 5.8GHz VTX that can be powered by a 1S (1-cell) battery - 3.7v-5v. Hey, that sounds like a simple and fun little project - I can do that. So they sent me one, and here we are. Turns out it's really easy to do. It doesn't really affect the way the H8 Mini flies, and doesn't seem to have any effect on battery life.
Basically you just remove the top cover of the quadcopter, cut out a strip of plastic to make a flat place to mount the cam/vtx, cut off the cam's power plug, and solder its power leads to the quad's battery connector on the main circuit board. It only took me a few minutes. While I had it apart, I also drilled a hole in the top cover to allow the H8's receiver antenna to stand up and maybe get better range.
Video quality from this little unit is surprisingly good. It comes with a cloverleaf CPL (Circular PoLarized) antenna already attached, so video dropouts are few and far between. Range is great - you'll lose visual sight of the tiny quad way before you lose video signal. It handles light/dark transitions pretty well, and is pretty durable too. I've crashed it into brick walls at full speed more than once (not on purpose of course!) and the worst thing that happened was the antenna got slightly bent. After several hard crashes I eventually felt the need to bend the antenna back, but the unit never gave me any trouble, even with a bent antenna. I may try bending the antenna's short cable back 90 degrees so that the antenna is not as tall, so it won't get so much damage when I crash. Otherwise, I love this little guy! Now I can practice flying FPV indoors on rainy/windy/hot days from the comfort of my home office chair, and not worry about damaging my house or hurting anyone.
So for about $60 (maybe less depending on sales/coupons/etc) and a few minutes on the workbench, you can have a fully functional FPV system - all you need is a receiver and screen or goggles. I was able to use the VRX and LCD screen I already have for my ZMR250 clone - all I had to do was press a button to change the channel on the VRX.
I can see lots of great applications for this unit. In fact I am going to see if I can mount it on my son's little toy RC car - it probably has a 1S battery inside since the car charges via USB, so adding the camera will be just as easy. I might add a little "roll cage" to protect the camera and its antenna, since his car likes to flip when you hit big enough bumps/jumps due to lack of suspension, but that's pretty simple too. If I end up doing that, I'll be sure to update this post with the video. :)