My 2018 Christmas jumper project uses a BBC micro:bit, replacing the earlier 2016 version which used an Arduino Nano. This has the advantage not only simplifying the project just also allows me to activate the jumper using the inbuilt accelerometer whenever I move.
The final software allows the jumper LEDs to be activated in four ways
- By holding down button A
- For 5 seconds by momentarily holding down button B
- by moving the micro:bit, option is enabled and disabled but holding down both buttons simultaneously
- Using the Radio function - sending the word ‘on’ to radio channel 0, activates the LEDs for 5 seconds, you can cut this short but sending ‘off'
The hex file for the s/w is attached. Download this to the micro:bit in the normal way - check the micro:bit website if you are unsure how to do this (https://microbit.org/).
- All the flashing jumpers I have seen have a hidden pocket on the inside lining that holds the battery enclosure, locate the enclosure and remove it being very careful not to pull on the wires going back into the jumper.
- Open the battery enclosure ( you may need a small Phillips screwdriver to do this ) and remove the batteries.
- Connect one crock lead to the positive battery terminal and a second to the negative terminal
- Connect the other end of the crock lead connected to the positive battery terminal to the micro:bit P0 connection
- Connect the other end of the crock lead connected to the negative battery terminal to the micro:bit GND connection
And that is it. Make sure the switch on the jumper battery enclosure is set to 'on' and power up the micro:bit
- Hold down button A - the jumper will stay on while you hold the button
- Hold down button B momentarily - the jumper will illuminate for 5 seconds
- The movement option is enabled and disabled but holding down both buttons simultaneously. when enabled the jumper will illuminate for about a second whenever you move. You can adjust the sensitivity by modifying the code.
- Sending the word ‘On’ to radio channel 0, activates the LEDs for 5 seconds, you can cut this short but sending ‘OFF'
You can make it more permanent by replacing the crock leads wire connections if you want.