DEI 508D Field Proximity Sensor

I'd like to hook up a DEI 508D Field Proximity Sensor to an Arduino.

It's a 12V circuit, it has two outputs which I'd like to sense.

The green wire is "First stage (-) 200mA output (500mS)" The blue wire is the "Second stage (-) 200mA output (1S)"

How would I go about sensing this using an Arduino?

This is the "manual": http://www.directeddealers.com/manuals/ig/accessories/2508111_508d_installation_guide.pdf

Hmm, rather unclear that document (and my neck now aches :)

I think it might mean the outputs are open-collector capable of 200mA sink. However I'd suggest it would be best to measure.

Measure the output voltages with nothing connected, and then again with 10k resistor from output to 5V. If only the latter works and gives 0..5 range, then open collector it is. If both generate an output then take note of the voltages involved. If 12V you'd need a level shifting circuit such as resistor divider.

Without a resistor, it measures 0V when inactive, about 6.7mV when triggered.

With a 10K resistor connected between the output and the 16V rail (sorry, no 5V available right now), it reads 15V at the output when inactive, but drops to zero when triggered.

That means it's grounding, right? How would I sense that, and is it OK to connect that resistor directly to the Arduino's 5V power even though this runs on car 12V?

Thanks for your help!

Yup, run a 10k resistor or so from the output to +5V and it'll become a nice 5V logic signal. Open-collector (or open-drain, same thing) outputs are nice and flexible like this (you can wire several of them together to one pull-up resistor to make a hard-wired AND gate too :)

Great, thanks so much for your help! I took a few electronics courses back in college, but have forgotten most of it. Now I'm starting to see what the term "pull-up resistor" actually means!

Again, thanks!

I'm also trying to use this sensor, but confused about what the blue and green wires do. Is there something I can read online to get a better understanding?

Check the PDF Manual: http://www.directeddealers.com/manuals/ig/accessories/2508111_508d_installation_guide.pdf

The green wire is the "warning" - someone's entered the larger warning perimeter. The blue wire is "alarm" - someone's entered the smaller alarm perimeter.

id628: Check the PDF Manual: http://www.directeddealers.com/manuals/ig/accessories/2508111_508d_installation_guide.pdf

The green wire is the "warning" - someone's entered the larger warning perimeter. The blue wire is "alarm" - someone's entered the smaller alarm perimeter.

I understand that part, what I don't understand is how to use those wires in a circuit with the Arduino (even after the previous explanations).

I know thread is old. But I found good input to the initial problem under: https://hackaday.io/project/2656-arduino-controlled-car-alarm

"... When I first tried hooking this up to my Arduino I was worried about the sensor running on 12v. I didn't want to pass that voltage into the Arduino and fry it. Eventually I realized that the signal pins are left floating when the alarm is not triggered. When the alarm is triggered the signal pin is connected to ground. This means you can connect the signal pin to a Arduino digital input pin, but you need to connect it to a pull up resistor so you get a constant value. ..."

I just ordered mine and had the same questions in mind.