We are using makecode to program the microbits.

Unfortunately setting up the WebUSB mechanism needed to program the mircobits via USB from Chrome, Chromium or Edge on Linux is causing some trouble.

• Shreya's and copilot's howto: microbit_troubleshooting.pdf

Download the .sh (bash script) file below to your Downloads folder by clicking on the blue title.

prep_microbit_on_ubuntu.sh

set -x
wget https://dl.google.com/linux/direct/google-chrome-stable_current_amd64.deb
 
apt update
apt install ./google-chrome-stable_current_amd64.deb -y
apt install google-chrome-stable -y
 
echo 'SUBSYSTEM=="usb", ATTR{idVendor}=="0d28", ATTR{idProduct}=="0204", MODE="0666"' > /etc/udev/rules.d/99-microbit.rules 
 
udevadm control --reload-rules
udevadm trigger

Then follow the steps given here:

cd ~/Downloads
chmod 755 prep_microbit_on_ubuntu.sh
sudo ./prep_microbit_on_ubuntu.sh

Building our own micro:bit robot kit.
Requirements:

• powered by a mini 5V USB powerbank (e.g. 2000 - 3000 mAh),
• The Micro:Bit power input is 3.3V regulated, via the 3V skrew connector (conductive holes),
• driving two SG90 micro servo motors (360°) with wheels (not the yellow DC motors), powered by 5V
• level shifter for the servo control signal from Micro:Bit 3.3V to 5V for the servos
• driving at least one additional servo motor (360° or 180°) for further action,

Pictures from the Keystudio Wiki:
https://wiki.keyestudio.com/MB0102_Keyestudio_Microbit_Main_Board_%2BUSB_Cable%2BBattery_Holder_with_Batteries

• https://github.com/microbit-foundation/microbit-v2-hardware
• microbit_v2.2.1_nrf52820_schematic.pdf

• out: Vout = 3.3V fixed,
• in: Vin = 5.5V max,
• current: Imax = 300mA
• datasheet: NCP114BMX330TCG

NOTES:
Read the annotations on the regulator schematic! The board can have FOUR power input sources.

1. 5V USB via USB connector
2. 3V - 4.5V via battery connector (skrew terminals)
3. “lozenge” (Pastille, Raute) shaped power pad, connected to Vout of NCP114
4. 3V - 5V typ. from edge connector

It is weird that the power input from the edge connector is directly connected to the voltage output pin of the LDO! Do I (rb) understand this correctly?

• lsm303agr.pdf

• no power regulator
• no motor drivers
• just a buzzer
• works for V1 and V2
• https://www.electroschematics.com/microbit-2/

• voltage regulator 5V → 3.3V
• logic level shifter
• https://wiki.keyestudio.com/KS4030_Keyestudio_Microbit_Expansion_Board

ATTENTION: 180° ONLY!

Original source: https://www.monkmakes.com/mb_servo_kit

Distributors:
RS Online: https://de.rs-online.com/web/p/bbc-micro-bit-add-ons/2048260
RobotShop: https://eu.robotshop.com/products/servo-controller-microbit-monk-makes
okdo: https://www.okdo.com/de/p/servo-kit-for-microbit/

https://www.monkmakes.com/mb_servo_kit

https://eu.robotshop.com/de/products/servo-controller-microbit-monk-makes

Original source: https://kitronik.co.uk/products/5673-kitronik-simple-servo-control-board-for-bbc-micro-bit

https://kitronik.co.uk/products/5673-kitronik-simple-servo-control-board-for-bbc-micro-bit

• Datasheet: 5673-kitronik-create-simple-servo-control-board-datasheet.pdf

Distributors:

• RS Online: https://de.rs-online.com/web/p/bbc-micro-bit-add-ons/2663768
• RobotShop: https://eu.robotshop.com/products/kitronik-simple-servo-control-board-for-bbc-microbit
• …

Original source: https://kitronik.co.uk/products/5694-compact-16-servo-driver-board-for-the-bbc-micro-bit

Datasheet:
5694-kitronik-compact-16-servo-driver-board-for-microbit-datasheet.pdf

Datasheet of PCA9865 at NXP:
PCA9685.pdf

Adafruit tutorial on PCA9865:
https://learn.adafruit.com/16-channel-pwm-servo-driver/overview

Features:

• Operating Voltage (Vcc): 3V to 12V
• Number of Servo channels: 16
• Servo Voltage: Same as input Voltage
• Max continuous current (all servos): 10A

ATTENTION: 180° ONLY!

Distributors:
AZ-Delivery: https://www.az-delivery.de/en/products/az-delivery-micro-servo-sg90?variant=12236813336672