Interfacing The CO Gas Sensor Module (#27931) to an RFID Tag ??

hamad

Greetings all,

I'm currently working on a course project that involves interfacing the CO Gas Sensor Module (#27931) to an RFID dry contact tag. I've tried doing that via a relay but no luck.

the question in hand is: do I absolutely need a microcontroller for the interfacing to work properly ?? or would a relay do the job? because in the datasheet it keeps going on about using a MC such as the Basic Stamp.

another thing I'm wondering about is the Heat Switch (HSW) input to the module; what is it exactly? is it ok to just ground it and go from there? because the datasheet also says "Heat switch input from microcontroller, active low"


you'll find datasheet links of both sensor module and tag below.. any help is much appreciated




CO Gas Sensor Module (#27931) datasheet:
http://www.antratek.com/pdf/27931_C0_GasSensor_v1.0.pdf


RFID Dry Contact Tag (RFCode R130) technical specs:
http://www.rfcode.com/images/tech_spec_sheets/r130_tech_spec_sheet.pdf



Best regards,
Hamad

Franklin

Dry contact is a switch closure (infinity = open, 0 ohms = closed) the CO2 sensor puts out 0 to 5vdc so you would need some parts that look for 5v and close a set of contacts. A relay would do that.

hamad

Thanks a lot franklin, That's what I was thinking as well..

That leaves my second question: what about the heat switch input (HSW) to the sensor module (active low), is it necessary to use a microcontroller for that or will grounding do the job ??

Franklin

I'm currently working on a course project

Would this project not include reading the datasheets and figuring out what is needed for yourself? I know that these days 'research' consists of getting on line and asking others for the answers to the questions but I don't have time right now to help.

hamad

As I said, thanks a lot Franklin. I appreciate your help. However, you're not the only one in this forum and I was asking my second question to whoever knew about this. If you don't want to answer, you don't even have to reply. Your last reply is appreciated though

Also please keep in mind that I didn't post this thread until I went through all related datasheets, searched online, asked the professor and even emailed parallax's support about it. Unfortunately no response till now.

So, everyone else, what about the heat switch input (HSW) to the sensor module (active low), is it necessary to use a microcontroller for that or will grounding do the job ??

Mike Green

If you look at the Module documentation and sample program's comments, you'll see that the heater needs to be turned on for about a minute before measurement is done. A microcontroller would normally do that timing for you. There's no reason why you can't do that sort of timing manually by grounding the HSW line for a minute. I'm sure the heater is not designed for continuous use (leaving it on all the time) and I believe the sensor won't work if the heater is on because any CO would be driven off the sensor by the heat. That's why it's called a PURGE cycle when the heater is on for a minute. Again, read the documentation. I have no special knowledge ... I got all this from the documentation.

hamad

Thank you Mike. I read the documentation again and found out that I didn't understand the word PURGE properly (English is my second language.. I know, my bad). but the way you put it now makes much sense after reading the datasheet.

For now, I know (according to the sample program) that the HSW input is needed mainly before measurements. Hopefully, that'll work.


Again, I appreciate your help, Franklin and Mike. This post is closed for now I believe.