“Binary displays are very popular for clocks so it looked like there a gap waiting to be filled in the measurement area with an instrument that displayed its results in a Binary format. As result I decided that a DVM would be a suitable project to be given a Binary makeover.
The Microbit has the means via an ADC (Analogue to Digital Converter), to convert analogue inputs into digital values. These digital values can then be used to create a myriad of applications.
In this case I will describing how to make a Battery powered Digital Volt Meter (DVM), but in addition to this I will have the ability to display the voltage in Binary as well as the usual Decimal values.
NOTE ENSURE THAT ANY VOLTAGE DIRECTLY APPLIED TO THE MICROBIT DOES NOT EXCEED THE SUPPLY RAIL (~3V), AS YOU WILL DAMAGE THE MICROBIT
If you were to apply a DC input to the ADC this being limited by the supply would mean that ~3V would be the maximum.
However, there is a way to overcome this limitation with a few additional components to measure voltages greater than the supply without causing damage to the MicroBit.
It must be noted that there is a limitation to what this simple DVM will measure and its only intended for low voltage positive DC applications in this case 0 to 20V.
MicroBit - Qty 1
Battery Pack - Qty 1
9k resistor - Qty 1_
_953R resistor - Qty 1
200R multi turn potentiometer - Qty 1_
_1K resistor - Qty 4
*All resistors 0.1W or greater.
Veroboard - Qty 1
Veropins - Qty 3
Bread:bit Edge Connector Breakout Board - Qty 1 or similar to allow the Microbit to be connected to the potential divider.
LED red low current - Qty 2
16 pin DIL socket or SIL socket strip - Qty 1
PSU, fixed or variable voltage.
PP3, 9V non rechargeable battery.
In the absence of a PSU a battery as indicated may be substituted.
4 pin single in line (SIP), pin header - Qty 2”