Let’s examine the old controller
Here is the photo of the controller opened. The PCB that controls the operation and sends the data over the radio was already removed for this photo
This is 2-axis remote controller, so it has 2 potentiometers. The potentiometer is basic electronic device that consists of turnable variable resistor with 3 wires.
When the user rotates it, the resistance changes. It’s first and third wires are connected to power and ground then the middle wire becomes the output of the voltage divider. This voltage can be used by the ADC of the microcontroller.
Now if we replace this potentiometer with any other one then it should still work without any changes in electronics.
Lets go aliexpress and search for “Gimbal spare parts”. We will find the following
Huge variety of them! Which one suits our task? Almost anyone. The only thing you should check that the gimbal is resistive type. The other type that we don’t want is called “Hall-effect gimbal”.
Our gimbal has 6 wires. It is basically just two potentiometers.
The case
The case must be light and durable. I chose PETG as a material because it is flexible and does not break that easily like for example PLA.
How usually this type of gimbal in mounted to the case? Normally it is secured with 4 screws that go through the front wall to 4 standoffs like so:
I didn’t want to have any screws on the front. I decided to design the custom press fit connection. Special 4 holes in which 4 standoffs of the gimbal will be pressed and be secure even without any glue. You can see 4 of those “craters” on the next image.
Now lets have a look at the whole assembled controller with back cover removed.
The PCB has this strange shape because it was designed to fin into the pistol-style controller. It has 4 buttons for adjusting the maximum speed and steering limit, one potentiometer for steering calibration, one power switch that is constantlt turned on because the other one is use instead (large switch on the front panel). Because I am replacing 2 potentiometers with another 2 potentiometers there is no need to hack electronics further. I only needed to colder those 6 wires together because the connectors were different.
One important thing about gimbals!
In order to secure them you need to know the exact dimensions of the mounting pegs. They are not always correctly described on aliexpress listings and the sizes are different between the models.
You get any random gimbal it will not fit into my case. If you want to replicate my controller I advice you get the exact same gimbal that I got so you don’t need to change the case.
The same problem is with the car. The controllers are a little different between manufacturers and PCB inside of them are different. PCB from another car will probably not fit on to the mounting holes that I have. You have to options: buy the same car that I got or change the case for your PCB.
Here are the design files.
You can have a look at other things that I made here
