Has anyone used this?

[brodin]

http://www.elfa.se/elfa/produkter/en/4898.htm

I have bought one of them(9901). But i don't know how to use it =)

It only has 3 pins: GND, DET+ and DET-

I find no info in the datasheet what the pins are for, and how the output signal works.
Is there a variable resistance between DET+ and DET-? But how is the sensor powered then?

I find no info about voltages or max.current in the datasheet either.
Du you have any ideas?

I am going to use it to meassure the temp on the rear-tyre on my motorcycle when racing.

[G8RPI]

Hi Brodin,
I've not used these sensors but know a little about them. They are thermopiles (a number of thermocouples connected in series). Thus they generate a voltage that is dependent on the temperature difference between the front (heated by the I.R. radiation) and back (attached to the case). The energy is supplied by the item measured so no supply is needed. Try connecting the + and - outputs to a digital multimeter set to volts and see what you get out. You will need to amplify the signal ( try an istrumentation amplifer IC) before you connect it to an ADC. You also need to measure the temperature of the sensor as it only detects the difference between it and the object being measured.
The data sheet is not very helpful, try searching for application notes. It may be easier (but more expensive) to buy a complete module with a conditioned output.
Hope this helps,
Robert G8RPI.

[mat janssen]

Hi Brodin,
I have asked the firma who made this product for an application note how to use this.
Up to now I do not have an answer.
If I get one I will put it here,
I have looked to a simular one.
I found that when you take a operational amplifier with a high input impedance connect it as an inverting amplifier
connect at the input resistor the DET- .
The DET+ and the GND connect that to the 0 volt of the amplifier
circuit.
The gain of your system you have to findout youself.
Choose one so that you have a voltage output of about 3 volts in your working area.So the PIC ship has a good resolution of your problem.

[brodin]

I talked to the firm via phone today. It works exactly as G8RPI said. It need to be amplified.

Can you give me an example on an amplifier IC that would work.

Isn't it possible amplify it with a single transistor?

[mat janssen]

Sorry but it is not possible to use a single transistor for this
device because of it's internal resistance and it cannot deliver enough current and with a single transistor the sicuit is not linear to its temperature so you must use an oppamp.
see atachement

[brodin]

Okay! Thanks for the scematic!