Car voltmeter on Attiny13 (battery charge indicator)

[Vermes]

In winter, accumulators sometimes cause problems. It is a simple voltmeter, which signals the voltage at the battery terminals.
Signalling is done using 3 LEDs:

• green flashing: U>14,5V (overload)
• green lighting: U>14V and U=<14,5V
• green and yellow lighting: U>13.5 and U=<14V
• yellow lighting: U>13V and U=<13.5V
• red and yellow lighting: U>12.5V and U=<13V
• red lighting: U>12V and U=<12.5V
• red flashing: U<12V (discharge)

The whole is controlled by Attiny13 processor, the device is closed in a housing from an old car power supply for a mobile phone.
Yellow round LED signals powering the system after stabilizer 7805.
The program was written in BASCOM and takes about 99% of processor memory.
The board was designed in Eagle and made in thermal transfer method (laser printer + chalky paper + iron). All was protected from oxidation with Plastik70 varnish.
Photos:



Link to original thread – Woltomierz samochodowy na Attiny13 (wskaźnik naładowania akumulatora)