Simonas asked Rokas if he could make an alternative remote controller for DJI Ronin camera gimbal he had. The goal is to be able to position the camera to a desired absolute attitude/heading (commanded by absolute orientation of another wireless “master” device). I.e. the camera on gimbal should mimic the orientation of the operator’s controller device.

Challenge accepted.

First step - connect to gimbal’s D-Bus input and try to move it around a bit. D-Bus seems to be just a renamed version of Futaba’s S-Bus, which, in turn, is not an open protocol. Luckily, guys at mbed.org (https://developer.mbed.org/users/Digixx/notebook/futaba-s-bus-controlled-by-mbed/) did a good job reverse engineering it. Due to hardware limitations Rokas had to bit-bang instead of using hardware UART, but it worked:



Second step: add IMU. Now it basically works as a joystick in relative control mode (only controls the speed of movement vs. absolute positioning). There’s also a WiFi (ESP8266 of course) on board, but only for debugging yet.

Next steps: mount this board on the camera holder and write a piece of software that would accept remote commands and feed it to PID controller to position the camera to the desired orientation. Not sure yet what this device will be (smartphone/tablet or another custom board) and what wireless link will be used.

To be continued, so stay tuned.