DIY Auto turn-OFF featured cheap Digital Multimeter
Updated: Oct 25, 2020
A wonderful design that enables you to add an Auto-OFF feature for 15 mins in your old and cheap digital multimeter(DMM) is presented here. With this you can save your battery consumption even if you forgot to turn-OFF your DMM.
To add the Turn-OFF feature, you will be requiring a very few components like - microcontroller (tiny25 in the present case), a voltage regulator, a npn-transistor and the associated capacitors and resistors. The circuit is powered from the multimeter 9V battery and cuts off the ground path to the meter to turn off its power.
To request for complete design steps, including the source code and Eagle based circuit schematics, write me at ashish[at]aries[dot]res[dot]in.