Hi guys
I need a way of keeping under control the alternator of my bike, I was thinking to build a low voltage warning light like the one in the car dashboard
The idea is that with the engine running if the voltage at the leads of the battery drops below a threshold the red light comes on!
Is that doable without using a Pentium 4 processor? Any idea how?
I think you can do that with just simple components, although you would need to adjust the input current and voltage with another circuit.
A quick google gave me this http://www.learningaboutelectronics.com/Articles/Voltage-sensor-circuit.php
it turns a light off when the voltage drops below 5V
There are many ways to do this without microcontrollers:
https://www.google.co.uk/search?q=low+voltage+indicator+schematic&tbm=isch
You’ll probably want some kind of a comparator circuit with a fixed voltage reference.
You set the reference for the comparator using the voltage dividers.
Theory of operation is, you get a constant 5V from your 7805 (or whatever), then you divide your battery voltage with a voltage divider, so you get a voltage which is 25% of the input (so 12V becomes 3V), you can then set the reference input to the comparator to be the low voltage trigger (so if it’s 10V, you set the reference to be 2.5V by dividing 5V down to 2.5V with, say, 10k/10k).
Output of your comparator goes to an LED.
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