A blast from the Elektor archives: this 1998 battery tester uses a simple LED display to reveal a battery’s true condition under load — even below 1 V.

This expandable LED display for a microcontroller in Figure 1 has a simple interface with only 6 data/control wires and can be easily accommodated to a DIY design. The display has static indication.

This design idea (Figure 1) shows how easily “new flesh can be added to the old bones” and how some new functions can be added to the simple LED display that was published earlier. Figure 1 Upgraded ...