How to control a CuteBot robot car so it always faces you from a fixed distance, using a Person Sensor from MicroPython on a BBC micro:bit board.
The Person Sensor from Useful Sensors is a small, low-cost hardware module that detects nearby peoples’ faces, and returns information about how many there are, where they are relative to the device, and performs facial recognition. It is designed to be used as an input to a larger system, and this example shows how to program a CuteBot to follow you using a Micro:bit board with MicroPython. For a full developer's guide, see usfl.ink/ps_dev.
To build this project you'll need:
- Micro:bit board.
- CuteBot robot car
- Person Sensor from Useful Sensors.
- Qwiic connector cable with male pins.
The CuteBot should come almost fully assembled. Test to make sure that you're able to run simple sample programs like forward/reverse according to the manufacturers instructions.
Now remove the micro:bit from the car and slot it into the breakout slot on the CuteBot. Plug one end of the Qwiic cable into the socket at the top of the person sensor and then the male connectors into the I2C connector on the robot, marked IIC, which is the row of female connectors behind the sonar interface.
The order, from left to right with the LEDs of the Micro:bit facing you, should be GND (black), VCC (red), CLK (yellow), and DAT (blue). Confusingly this is almost the same as the Qwiic connector order, but with CLK and DAT flipped.
Now if you power the micro:bit board, you should see the green LED on the person sensor light up when you point it at yourself. Fix the person sensor to the top of the Micro:bit, so that it's facing horizontally forward. I've used Blu Tack to fix it in place in this example:
Create a new project in the Python micro:bit editor.
Click on the Open button, and choose the main.py file in this folder. Then
choose Open again and select the Cutebot.py file. When you're asked if you
want to replace main.py, click on a small icon to the right of the dialog and
pick the option to add it to the project under its original name. Make sure you
have your micro:bit plugged in and click Send to micro:bit to upload the
program to the board.
After it has uploaded, place your Cutebot on a flat surface and move so the
sensor can see your face. You should find that the robot rotates to face you,
and moves forwards and backwards to keep you about two feet away. If you move
from side to side it should follow you, and it should also move to keep about
the same distance from you. You can alter the speed, distance, and other
behaviors by modifying the constants around line 34 in main.py.