software resources for science and technology education
Mr Bit 2D Models
Building models which you can control with your micro:bit is easy with Mr Bit 2D Models!
The Mr Bit Model Heating System is one of nine 2D models designed for the BBC micro:bit.
The Mr Bit cartoon, a full list of components and instructions for building this model and eight others are available for free download.
All the components for the model are mounted on an A4 stiff card. In this case we use LEDs, a temperature sensor and a small electric motor. Simple terminal connector blocks on the back of the card are used to secure the connections which can all be made with a screwdriver.
The LEDs and temperature sensor each need a resistor connection and the motor needs a transistor. Details of these are given in the free download instructions below.
The micro:bit is also mounted on the back with an opening in the card to show the LED matrix and buttons.
Mr Bit Model Heating System
The model heating system has a boiler which can be controlled with the micro:bit buttons and a temperature sensor.
- The flickering red LEDs represent the flames of the gas burner and a small motor represents the water pump.
- Touch the temperature sensor to heat it up and watch the boiler switch off when the temperature reaches a programmed value.
- Cool the sensor down with a damp cloth and watch the boiler switch on again.
For controlling the boiler, you can write the program in your favourite code editor or with the Mr Bit program.
Typical instructions for coding might be:
When button A gets pressed, switch on the burner until button A gets pressed again or it is warmer than 25 degrees.
Show the temperature on the LEDs until the pump is on.
When the pump is on show the LED message “HEATING ON”.
When the burner is on and button B gets pressed, switch on the pump until button B gets pressed again or the burner goes off.
When the pump is on, switch on the radiator until the pump is off.
Temperature sensor connections
Motor with transistor
LED connections
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