LEGO Power Functions #7/EN: NVIDIA Jetson - PCA9685 motor/servo control

[@heinrichhelmbold419]

This is excellent and thank you for posting this. One question... The link in the description references the money counter code on Github, any chance you can share the code you used for the servo/motor using the fps? Thank you again for sharing your knowledge

[@steinheilig7926]

You can find Inference_MotorControl.py in the Git repo. Section "# 1) Controlling LEGO Power Functions motors and servomotors" demonstrates how to control a LEGO Power Functions servo and a motor (in the given example to drive the money counter) using the Python Adafruit_PCA9685 library.

[@teocrito1966]

Really nice applcation using Lego + Jetson Nano. Since I am trying to do a similar task for a Lego Toty . Do you have any suggestion for the installation in the dusty-nv/jetson-inference Docker Container ? Thank you.

[@steinheilig7926]

Hi, thanks for the comment. Unfortunately, I cannot help you with this specific question.

[@merondesta3895]

that was interesting. i am using 4gb jetson nano board and i wanted to control servo motors of 3DOF robot arms do i need that h bridgn?

[@steinheilig7926]

You should never connect / drive a motor with the Jetson directly, because it could damage the board. Use a H bridge or the PCA9685 to separate the control (Jetson board) from powering the motor (with an additional power source). Since the PCA9685 offers 5-6V output, depending on the motors you want to drive you might need a motor bridge. LEGO motors need 9V, that's why I used the additional H-bridge (they would run though with 5V but slower ;) .

[@poisonedpotato5307]

Where did u get the jetsen nano i cant find it in my local store

[@steinheilig7926]

Seems to be difficult to get one at the moment for a reasonable price (~100$). You might check the Nvidia web page: developer.nvidia.com/buy-jetson?product=jetson_nano&location=US

[@steinheilig7926]

BTW, you might try an Arduino for motor control and if needed your PC (with webcam) for computer vision inference. Since the Arduino has a couple of PWM channels you might not even need a PCA9685...