Add a Flip Button to a Quadcopter Remote

Many small quadcopters use one of the two joysticks for controlling flips (typically the pitch/roll stick). Pressing down on the stick enables flip mode, with the direction of the flip controlled by the direction the stick is then moved. This system works well, but is cumbersome when trying to perform more acrobatic maneuvers, such as barrel rolls. For these advanced tricks, a separate flip button can be easier to use. Thankfully it's not too difficult to add a button, even on a tiny nano sized remote. This is how I added a flip button to my Eachine H8 remote.

Tools:

• Multimeter
• Soldering iron
• Screwdriver(s)

Materials:

• Remote controller
• Small momentary on/off button
• Wire
• Solder
• Insulation tape

I scavenged a button from another (broken) quadcopter's remote control, and was lucky that it had wires already soldered to it. Any sort of momentary on/off switch will do the trick, just make sure it's small enough to fit inside the remote control.

The first thing to do is work out where the new switch should go. I first held the controller as I would while flying, and noted where my fingers rested, so that the switch would be easy to reach. Exactly where the switch ends up will be determined by the space available inside.

Open up the controller, and check what space is available around the area you want the switch. The switch that I scavenged from an unused controller was alreadysoldered to a small circuit board. I found that there was just enough room between the case and the circuit board for this small board to be mounted.

I used a hobby knife to cut a square opening about the right size, then enlarged it as needed with a needle file. The final fit was tight enough to hold the switch via friction, but it would probably be more robust to glue it in place. I put a small piece of electrical tape on the back of the switch to prevent short circuits, then screwed the main circuit board back in place.

After removing the controller's circuit board, I flipped it over to find the flip switch. I then located the appropriate solder pads on the reverse side of the board. The switch in my controller has 4 leads, 3 of which are soldered to the circuit board. The switch should short two of these out, it's just a case of working out which ones they are.

I grabbed my multimeter, and put it into resistance mode. I put the leads on two of the pads, and checked the resistance, which was 0Ω. I then put one of the leads onto the other soldered connection, and got a reading of ~ 1.5MΩ. This should be the switch. Clicking the stick in while holding the leads in place was tricky, but when I eventually managed it the multimeter read 0Ω, meaning I'd found the right pads to solder my switch to.

I soldered the wires from my switch in place, being careful not to short anything out in the process. If you have a switch without wires, then you'll need to solder a wire onto each side of the switch first, making sure to leave enough wire to reach the solder pads on the controller circuit board. Once that's done you can put everything back together and test it out. Or, if you're cautious like me, test it out first before putting everything back together.

Unfortunately I was unable to test the controller with the quadcopter, as it currently has a burnt out motor, but I was still able to confirm that the switch appears to operate as expected. I turned the controller on, and bound the controller to the quad as normal. The controller is still able to spin the working motors, so that's a good sign that I didn't fry anything.

When the stick is pressed in, the controller beeps to indicate that it's about to flip. I pressed my new switch, and was rewarded with a beep. So, everything is connected, and working as best as I can tell. The final test will come once I have 4 working motors in the quad, and can confirm that it does flip as expected.