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Topic: Help Me Brothers and Sisters for i am in need!! (Read 547 times) previous topic - next topic


I wonder if there are any clever people who would be able to help me with a little project that i am trying to do. i have two things that i whish to achieve: -

I have a 12v lesure battery and would like to save money and make my own battery monitor / power indicator so this is what i would like to do

I wish to have 12 LEDS with each pair of LEDS representing 1 volt, starting at 10V ending at 14v then i will be able to do the following: -

LEDS Number 1 - 10 Left to right

1&2 - Red - representing 10V
3&4 - Yellow - Representing 11v
5&6 - Green - Representing 12V
7&8 - Green - Representing 13V
9&10 - Red - Representing 14V

My problem is this i do not know how to wire this up using resistors etc to display the correct voltage value and protect the LEDs Is this possible to do without using my Arduino?


I have this working (of a fashion) I have two Groups of 4 LEDS 4 green 4 red these are connected to a push switch that when activated lights up. My Problem again similar to the first is i wish to press the button and only see Green if the battery sits between 11.5 (or 12v if it is easier) and 13 and it only light the red leds if the voltage is less than 11v Again is this something i can do without my Arduino?

Thank you so much in advance for you help

Mr Confused


You could probably  do this easily with an LM3914 (do a google on "LM3914 voltage monitor" for some ideas/schematics)...
I will not respond to Arduino help PM's from random forum users; if you have such a question, start a new topic thread.


If you still want to do it with an Arduino, you need a voltage divider an an analog input, and use the digital pins for the Leds. Since arduino can only handle voltages from 0 to 5V, you need to divide your input by 3 (more or less). So a voltage divider using a 10K and a 4K7 resistor will do the job.

Just wire Vout to the Analog input and then do the software.

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