Electronics Manual for Calliope mini

Minimal set of electronic components

To get started with cardboard robots you need a really small set of electronic parts:

Calliope mini minimal set of electronic parts for building Cardboard Robots
  1. Calliope mini
  2. Jumper wires
  3. 2 x AAA battery pack – with AAA alkaline batteries
  4. One servo motor – depending on the project 180deg or 360deg (so in fact you should have two of them, but only one can be connected at a time)

With this setup you can get a really cheap robotic kit that will allow you to make all of our one-motor projects.

With a help of the jumper wires you can connect the servo motor directly to the Calliope mini, even tough the board can provide very little power directly from the 3,3V pin (about 90mA) it is barely enough to power one micro servo.

PROTIP – Micro servos with plastic gears (usually in blue housing) require less energy than the one with metal gears (usually in black housing like Tower Pro MG90S) – so if you plan to power it directly from the Calliope mini board choose the plastic blue ones

PROTIP#2 – If you power the board with AAA batteries you have to use ALKALINE BATTERIES they provide 1,5V each so two of them give you 3V which is already below required 3,3V but will get the board and one micro servo running for quite a while. Regular AAA Ni-Mh rechargable batteries like Eneloops etc. provide only 1,3V each so two of them give only 2,6V which is not enough to drive the servo.

Suggested electronic parts

  1. Calliope mini
  2. Micro servo motors – two types -180 degree and 360 degree (full rotation)
  3. SERVOBOARD for Calliope mini
  4. Magnetic micro USB-C cable

1. Calliope mini

Calliope mini is a microcontroller board dedicated to education in primary in high schools. The board can be seen as a sister project of the BBC Micro:Bit sharing a lot of electronic design and concepts. This allows Calliope gain a lot from Micro:Bit community and educational resources.

Calliope mini is much more capable than Arduino and much simpler to use than Raspberry Pi. Packed with built in sensors and wireless connection capability this board is great for a basic robot controller.

Calliope mini has plenty of onboard sensors:

  • buttons
  • accelerometer
  • magnetometer – compass and magnet sensor
  • light sensor
  • thermometer
  • capacitive touch sensor
  • analog pins
  • 3 RGB leds
  • speaker

For basic robotics projects you can easily go on with the builtin sensors so you need no extra accessories for the board.

2. Servo motors

The only external components you need to build a simple robot with a Calliope mini board are motors. We suggest using only micro servo motors as they can operate on 3.3 volt signal provided by the Calliope mini and you can get them in two modes:

  1. 180 degree – for pivots, gripers, arms etc.
  2. 360 degree – full rotation – for wheels

Before you start using servos be sure to prepare them by adding screws to attach the cardbiard. All the parts you need to do that come in standard servo package. See video below for instructions.

https://youtu.be/1HpvmV5ffBY

3. SERVOBOARD

The main limitation of Calliope mini when your goal is to build a cardboard robot is that you need some kind of adapter to connect motors and provide power supply. You can get an additional SERVOBOARD that clips to the Caliope mini extension port and provides connectors and power supply up to four servos and two DC motors.

With the SERVOBOARD Calliope mini is fully equipped for small and medium robotics projects covering 99% of possible school use cases.

4. Magnetic micro USB cable

This accessory is not necessary but it is ESSENTIAL to lenghten your Calliope mini board lifetime in school environment when it is tossed around from one kid hands to another.

Calliope mini is rather solid board with no specific parts to bend/break/tear apart but it weakest point is definitely a USB-C PORT. MakeCode software uploads the code only via usb cable and as you build a moving robot you will likely want to plug and unplug it many times uploading new iterations of your code and testing it. When this process is in hands of your inattentive teenage students damage of the usb port is only a matter of time.

Magnetic cable solves this problem, you only plug the connector to the usb socket once and then use the magnetic plug to connect the board to the computer. If your robot falls to the ground or moves unexpectedly, magnetic plug detaches and keeps the usb port safe.