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Low Battery Alarm

Low Battery Alarm

Difficulty
Power

Summary

Perfect for 12 - 24V boating applications! Use this adjustable low voltage alarm for your next time out and about to make sure you're never stuck with low power again. Uses a 2.5v reference with the 358 Dual op-amp to compare the battery voltage and to oscillate a small buzzer on the board if it gets too low. Wire in a small LED indicator light so you can see it on your dash

You will need some spare wire to connect to battery and LED.

What it does

This essentially hooks onto the battery and gives you two outputs when the battery goes below a certain level:

  1. constant 12V HIGH

  2. pulsing ground connection. (used for grounding the buzzer and making the alarm.)

With this, the idea is that you can hook it up to anything you want. for instance, a LED that warns you about "Low Voltage" could be connected on port 1. and the buzzer could be connected to port 2. or if you wanted a flashing LED and a constant tone, you'd connect the LED to 2. and a buzzer from 1. to ground.

Materials Required

1LM358 Low Power Dual Op-Amp Linear ICZL3358
1LM336-2.5 2.5V Voltage Reference TO-92 caseZV1624
110k Ohm 0.5 Watt Metal Film Resistors - Pack of 8RR0596
110Kohm Spectrol 25 Turn TrimpotRT4650
147uF 25VDC Electrolytic RB CapacitorRE6110
1Mini PCB Mount Buzzer 9-14VDCAB3459
1Small Breadboard Layout Prototyping BoardHP9570
22 Way PCB Mount Screw Terminals 5mm PitchHM3172
11N4148/1N914 Signal Diode - Pack of 5ZR1100

It's clear from the start we are trying to COMPARE the battery level, and so we'll need a comparator to do that.

I had some idea that there was a osciliator pattern online using a simple

testing steps 2

Future Improvements

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