micropython_legorobots

This repository is for the documentation of my LEGO compatible robot platform based on the esp32 and a 3D printed housing. Here are some videos of robots in action: https://www.youtube.com/playlist?list=PL1qkIXs3HI0etdAwmriiLkkrndSfr02LH Find more information here: https://makeprojects.com/project/brick-bots

hardware

pinout

components

• esp32 board: TTGO MINI 32 V2.0 ESP32 WiFi Bluetooth Module development board
• motor driver: wemos d1mini motor shield
  • firmware from https://github.com/pbugalski/wemos_motor_shield
  • i2c
• battery: 1200mAh 3.7V Li ion for small rc quadcopter (903052)
• motors: Mabuchi FF 180 FH
  • https://www.pollin.de/productdownloads/D310419D.PDF
  • official ratings:
    • voltage: 2,4 V- (1...3 V-)
    • current free/load: 130/700 mA
    • nominal power: 1,06 W
    • speed free/ load: 7700/6500 U/min
    • nominal/max torque: 1,56/10,0 mNm
  • driven from the battery (at max 4.2 V)
• motors: Noname geared hall effect encoder motors, advertised as 5V (but I have doubts)
• servo: mg90 metal gear
  • hobby servo pwm control at 50Hz (also works with other frequency)
  • torque: 2.5kgcm (~250mNm)
  • drops out if battery voltage gets lower (3.XV?)
• mpu 6050 Six-Axis (Gyro + Accelerometer)
  • i2c
  • speed: 250/sec to 2000/sec (see data sheet)
• range sensor vl53l0x
  • laser time of flight
  • i2c
  • maximum distance: 1300 mm
• neopixel
  • either one led directly on the box or 4 leds in a legobar

Planed components:

• Camera module based on AI thinker esp32 cam (running its own firmware)
• ir module?
• ultrasonic sensor module (mainly as they look so nice like eyes) and have slightly larger range.

micropython

esp32 firmware from loboris: https://github.com/loboris/MicroPython_ESP32_psRAM_LoBo The functionality and syntax of the modules differs from the official micropython ports. There is a good documentation in the wiki of the github page:

3D printing:

.stl and freecad files are available on Thingiverse: https://www.thingiverse.com/thing:3710047

robots:

The robots subfolder contains micropython code for different models

function_test:

Tests and example code for the different sensors, servos, and motors.

autonomous_car:

simple obstical avoidance

• uses one motor, servo for steering, vl53l0x range finder, neopixel bar (optionally)

self_balancing_robot:

• uses geared encoder motors, a IMU sensor, and PID algorithm to balance. At least in theory, its not working so far.