IR Transistor help

Something isn't working for me and maybe someone can help me I'm using this IR sensor http://www.kube.ch/downloads/pdf/kube_pyroelectric_c172.pdf

and I want to connect it to my Arduino. I'm using 5V as VDD , and the Signal(S) I'm connecting to the Arduino. my problem is that I get always 5V in the Signal leg I'm assuming the my problem is in the connection of the sensor. can someone help me maybe? or show me simple circuit I can build to cheek the sensor?

Thanks ,

We'll help you if you first help us.

Show us how you have it connected up, and we'll then be able to tell if it's connected right or not. Without knowing what you have done it's impossible to help you.

Also have you read the data sheet?

A source resistor is needed to set the drain current and consequently the operating parameters of the internal JFET. A 47 k? or greater value resistor is recommended. For low power applications (0.2 ?A), a source resistor of 3.3 M? can be used.

If you'd posted pictures or schematics we'd know if you'd done that or not...

this is a schematic of what I did
in very simple way…
the led is always on

Thanks ,

12.png

I'm not surprised.

I am guessing that your 5V is connected to Drain, though you don't show it, and the signal is actually Source, yes? Please label diagrams with what things actually are, not the function you are trying to have them do.

There is no example circuit in the data sheet, but going by what is said in the sheet:

  1. Drain should be connected to 5V.
  2. Ground should be connected to ground.
  3. Source should be connected to a 47KOhm (what's an oham?) resistor.
  4. The other end of the 47KOhm resistor should be connected to ground.

The Source pin, at its junction with the resistor, should now give an "active low" signal. When the sensor activates the output should go low, and when idle it should be high. That signal should be connected to a high impedance device, like an input on an Arduino. An LED would be too low impedance and would cause too much current to flow messing with the operating poing of the JFET.

This circuit is wrong. It cannot drive an LED directly with 220 ohms. Use 47000 ohms to Arduino input. Also, it does not work with a steady light, it senses motion of the light passing across 2 parts in the window. Move the light to get a signal output change. Pins 1 2 3 need labels on your schematic.

I have connected as you told me and I have connected a Volt-Meter at the the Source pin I can see it's getting 0.4V all time when I move or do something in front of the sensor It's doesn't change

Shine a constant flashlight on the sensor and move a block of wood across it so a sharp shadow moves to block the bright light. Move the block left to right. Move the block up and down to check all possible directions for the two parts of the tiny window on the tiny sensor.

didn’t help also
I think the board that is connecting to the sensor is damage
I will buy a but a new one and try again
maybe someone have the schematic of this board SE-10 ??

Thanks ,

https://www.sparkfun.com/products/8630

Please have a read on PIR motion detectors... They are designed to detect IR fluctuations so objects MUST move across the field of view.

Ray