DIY Electronic Bell Upgrade with TDA2822M Chip

If you're interested in DIY electronic bells, take a look at this article. In the previous DIY guide, DIY Electronic Bell for Mountain Bikes, the bell's sound might have been a bit too quiet. It works fine when there are fewer people and vehicles, but in busier areas, the volume just isn't enough. If you also think the sound is too low, keep reading.

If you have a TDA2822M chip, why not try a DIY project with it? The front circuit remains unchanged, but you'll need to replace the LM386-1 amplifier circuit with a TDA2822M (BTL) amplifier circuit. With an 8V power supply, the output power can reach about 1W. Adjust the 100K potentiometer to the 1/4 position, and the output volume will increase by about 1/3 compared to using the LM386-1. The total current will rise to 580mA. You don't need to increase the volume further due to concerns about the speaker's power limitations.

The TDA2822 is a low-voltage dual audio power amplifier IC.
Key features include:

· Wide supply voltage range: (1.8V to 15V, TDA2822M). It works even when the supply voltage is as low as 1.8V.

· Very low static current and cross-over distortion. The circuit can work in stereo or be configured as a BTL circuit.

· When working in stereo, the output power is 1W × 2 (Vcc=9V, RL=8Ω, THD=10%) or 110mW × 2 (Vcc=3V, RL=4Ω, THD=10%). The TDA2822M is a dual-channel design with a maximum supply voltage of 15V, maximum current of 1.5A, and a minimum input resistance of 100KΩ. When the input voltage is 9V and the output is 4Ω at 1kHz, the output power is 1.7W per channel.

In this circuit, the TDA2822 is connected in BTL mode, with a static current of 6mA to 9mA and an output power of over 1W.

The original LM386 circuit:

The modified TDA2822 circuit:

Finished.