Opto-isolation is a better idea. Something like this would work.
http://www.mouser.com/ds/2/205/CPC5902-740833.pdf
I2C AD converters are easy to work with using the Wire library. Just request the number of bits from the AD converter address. It's the same as using an analog in pin.
http://www.mouser.com/ds/2/205/CPC5902-740833.pdf
I2C AD converters are easy to work with using the Wire library. Just request the number of bits from the AD converter address. It's the same as using an analog in pin.
How would that work with a 0-5v analog input? A regular opto-coupler is not linear enough to output the voltage correctly (so I've been told).
Any room on your board to add this device or something similar in size? I would probably socket it just in case in blows.
I might be over thinking this, I simply want to trigger the board off when voltage goes too high. Resolution needs to be decent since the trip point may be from 3v to 3.1v
Any room on your board to add this device or something similar in size? I would probably socket it just in case in blows.
I might be over thinking this, I simply want to trigger the board off when voltage goes too high. Resolution needs to be decent since the trip point may be from 3v to 3.1v
You are overthinking this.
The AD converter would convert the signal from 0-5VDC to a binary value, then you read it digitally over an I2C bus(analog pin 4 & 5). Use the wire library in the arduino IDE.
Wire.requestFrom (AD converter address, number of bits it spits out)
If you are using a 8 bit AD converter it will convert to a number from 0 - 255. The opto-isolator stops anything bad from happening to the microcontroller.
But if you really want to keep it simple, look at the on board overcurrent (bias) sensing circuit Vzaichenko designed for this. It uses a voltage divider as you want to do. Tune it so the threshold voltage you want to trigger at causes current flow through the input of the opto-isolator, and read it digitally. Voltage goes high, opto-isolator pulls the input pin low and triggers the alarm.
The AD converter would convert the signal from 0-5VDC to a binary value, then you read it digitally over an I2C bus(analog pin 4 & 5). Use the wire library in the arduino IDE.
Wire.requestFrom (AD converter address, number of bits it spits out)
If you are using a 8 bit AD converter it will convert to a number from 0 - 255. The opto-isolator stops anything bad from happening to the microcontroller.
But if you really want to keep it simple, look at the on board overcurrent (bias) sensing circuit Vzaichenko designed for this. It uses a voltage divider as you want to do. Tune it so the threshold voltage you want to trigger at causes current flow through the input of the opto-isolator, and read it digitally. Voltage goes high, opto-isolator pulls the input pin low and triggers the alarm.
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My next evolution of boards have arrived. Lots to test!
Looks slick. Will be curious to get your test impressions.
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