Attiny85 1 5 Volt Cell Tester - An ATTINY85-based 1.5 volt cell/battery tester. Uses an OLED, driven with just two pins from the ATTINY85! The tester measures and displays the open circuit voltage of the cell, then places a 2 I'm having a trouble with my ATtiny85 chip my idea is to operate a relay shield with ATtiny85 chip and i'm using HC-05 Bluetooth and relay shield but the problem is that when i send a command to ATtiny85 through app it works fine for 1 or 2 relay (on/off) but when i turn "on" all 3 relays it should "on" but takes to much time to turn off back why ? Find updates at This page contains a collection of circuits that wink when the power switch is thrown to indicated whether the 1.5 volt (and other voltages near 1.5 volts) cell still has a significant charge left. Find great deals on eBay for 1.5 volt battery tester. Shop with confidence. Attiny85 1 5 Volt Cell Tester.