NXT volt meter

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NXT volt meter

Postby pEhrlich » Thu Jun 26, 2008 2:25 am

Hi

I'm planning to make a Lego dynamometer for testing the utility of various methods of lego propulsion. For this a volt meter would be handy. How easy would it be, from a hardware and software perspective, to detect the voltage and/or current across two wires on a sensor port?

--Peter
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Postby lawrie » Thu Jun 26, 2008 9:34 pm

The book "Extreme NXT" explains how to construct a voltage sensor. You connect a 10k resistor to Pin 1 and measure the voltage between the other end of the resistor and Pin 2. Pin 1 is the white wire and Pin 2 the black on a standard NXT connector wire. This measures voltages between -5 and +5 volts. You can read the voltage using the SensorPort readRawValue method. A value of 0 is -5v and 1024 is +5v.

You can construct a volt meter that measures between -15 and +15v with a 15k and a 30k resistor.
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