Trouble reading a high voltage into ADC for use with propeller video output
Branmuffin Industries
Posts: 35
I'm working on a propeller-based video display for our electric DeLorean that shows volts and amps. I have amps figured out, thanks to the LEM current sensors. I feed them into an ADC 0834, and set the vref, and everything works great.
As for voltage, I am trying to find the easiest way to read a voltage from 0-190 volts into an ADC. my first thought was a voltage divider with two resistors, which could bring a 0-200v analog down to a 0-5v analog signal.
However, it's never wise to connect battery/motor ground to chassis/digital ground. So, the ADC will have to use the battery ground as its Vref(-). As for its Vref(+), I can't use the built-in 5-volt regulator on my microcontroller board, because its using the digital ground. We're thinking of using a separate 5v regulator to generate the Vref(+5v) in relation to the battery ground. This regulator must take +12v-18v as a supply, and so a second voltage divider is used.
Does it seem that this is the easiest way to listen to the pack voltage and read it in to a byte variable so it can be drawn graphically on the screen?
See Attached Image.
If we get this issue resolved we should have a video up on youtube of us driving around and using this energy consumption video display very shortly.
-Ryan Brandys
As for voltage, I am trying to find the easiest way to read a voltage from 0-190 volts into an ADC. my first thought was a voltage divider with two resistors, which could bring a 0-200v analog down to a 0-5v analog signal.
However, it's never wise to connect battery/motor ground to chassis/digital ground. So, the ADC will have to use the battery ground as its Vref(-). As for its Vref(+), I can't use the built-in 5-volt regulator on my microcontroller board, because its using the digital ground. We're thinking of using a separate 5v regulator to generate the Vref(+5v) in relation to the battery ground. This regulator must take +12v-18v as a supply, and so a second voltage divider is used.
Does it seem that this is the easiest way to listen to the pack voltage and read it in to a byte variable so it can be drawn graphically on the screen?
See Attached Image.
If we get this issue resolved we should have a video up on youtube of us driving around and using this energy consumption video display very shortly.
-Ryan Brandys
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Chris Savage
Parallax Tech Support