Interested in a smoke / gas sensor?
Ken Gracey
Posts: 7,416
Hey there,
We're always working with new sensors. This one detects smoke - and I'm pretty certain it's used in commercial smoke detector designs. Perhaps some of you have seen these before. It also measures the presence of CH4, propane, alcohol and CO according to the datasheet (in Chinese). The version we're using is in a module which latches and handles the signal thresholds, though the raw sensor without the module's electronics provides a linear output.
In simple module form this works like the PIR - high for smoke or gas, low for nothing. I don't think we'd·be too interested in supporting the·sensor in raw format with an analog output, but it's also a possibility.
The module requires 12V and has a 5V output. I'm interested to know what our customers might think of this sensor. Below we're conducting some initial tests in which we used smoke, propane and particulate with positive results.·Raymond, one of·our engineers in China is demonstrating the sensor below. Unfortunately these tests made our office atmosphere really poor. And no, we don't normally smoke.
Ken Gracey
Parallax, Inc.
Post Edited (Ken Gracey (Parallax)) : 9/22/2008 3:43:33 AM GMT
We're always working with new sensors. This one detects smoke - and I'm pretty certain it's used in commercial smoke detector designs. Perhaps some of you have seen these before. It also measures the presence of CH4, propane, alcohol and CO according to the datasheet (in Chinese). The version we're using is in a module which latches and handles the signal thresholds, though the raw sensor without the module's electronics provides a linear output.
In simple module form this works like the PIR - high for smoke or gas, low for nothing. I don't think we'd·be too interested in supporting the·sensor in raw format with an analog output, but it's also a possibility.
The module requires 12V and has a 5V output. I'm interested to know what our customers might think of this sensor. Below we're conducting some initial tests in which we used smoke, propane and particulate with positive results.·Raymond, one of·our engineers in China is demonstrating the sensor below. Unfortunately these tests made our office atmosphere really poor. And no, we don't normally smoke.
Ken Gracey
Parallax, Inc.
Post Edited (Ken Gracey (Parallax)) : 9/22/2008 3:43:33 AM GMT
505 x 387 - 53K
600 x 450 - 51K
Comments
Would be neat of Tracy Allen shows up on this thread. He knows these kinds of sensors inside-out, along with their various flaws and benefits of different designs.
Ken Gracey
Now, onto business. Methane (CH4) detection is good. If it could also detect sulfides, that would be even better. As an example app, I have a hygrostat in my bathroom that controls a vent fan. A gas detector in parallel would be a most welcome adjunct.
But even without sulfide sensitivity, this looks like a nice sensor. Do you know what the base technologiy is for sensing such a wide range of gasses?
-Phil
*Ah, so. I see now: the disembodied hand in the first photo isn't yours after all.
Post Edited (Phil Pilgrim (PhiPi)) : 9/22/2008 4:18:02 AM GMT
I'm working on having him translate the datasheet so we can find out how this one works. The datasheet says it measures, H2, LPG, CH4, CO, alcohol, air (?) and provides humidity performance curves. Other than that it's all Chinese. I'll post it soon - we're going to lunch right now. Hunan food - going to be a rough one!
Ken Gracey
Parallax, Inc.
Chuck
suggests. Automatically turning on and increasing the speed of the fan (upon rising strength
of said gas) could help the bathroom wallpaper from peeling or the paint from discoloring...
Sorry,
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-Rusty-
--
Rusty Haddock <=> AE5AE
**Out yonder in the Van Alstyne (TX) Metropolitan Area**
Microsoft is to software what McDonalds is to gourmet cooking
Post Edited (Fe2o3Fish) : 9/22/2008 5:32:24 AM GMT
-Phil
_______________________
* Ref: Dr. James L. A. Roth, "Gastrointestinal Gas" (Ch. 17 in Gastroenterology, v. 4, 1976), cited here. (Hey, it's the first thing thing that came up on Google.)
without using the four-lettered word. It was entertaining and mildly educational to say the least.
Signed,
Flatulus Antiquitus
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-Rusty-
--
Rusty Haddock <=> AE5AE
**Out yonder in the Van Alstyne (TX) Metropolitan Area**
Microsoft is to software what McDonalds is to gourmet cooking
Yes, I'm interested. I'll contact you about lab testing some for quantitative sensitivity to different types of smoke. Most smoke detectors are based on either an ionization or light scattering principle. This device looks in your photo more like a catalytic detector, and that would be consistent with the gas detection, so I'm wondering if this device is really detecting the CO instead of the particulates.
I'm not sure if we have facilities available for unbiased testing of digestive byproduct gasses!
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Tracy Allen
www.emesystems.com
Hope you aren't testing for smoke and propane at the same time...hehe.
Is it safe to assume there is a way to switch between the diferent gasses you are measuring? Or, does it return a reading for all of the different gasses-like a data stream?
Thanks,
Dan
That's not how these sensors work. They don't have a separate sensor for each gas. The same sensor responds to any of the gasses listed or a mixture of them. These are used to detect combustion byproducts and are used for hydrocarbon fuel vapor detection like in bilges to reduce the risk of explosions.
A sub $20 price sounds great! Anyone done the CH4 testing yet? [noparse]:)[/noparse]
(I'll pass on the photos)
OBC
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Post Edited (Oldbitcollector) : 9/22/2008 10:44:54 PM GMT
I've used some of these CO sensors as seen here http://www.futurlec.com/Gas_Sensors.shtml with the Stamp many years ago. These are 5V AC or DC.
As long as there are examples posted to use it, I'm game. Would prefer it to be a RAW sensor instead of it being connected to a helper chip like an SX. Of course if you posted code for the SX helper chip, then that would enable us to use the SX proto boards as the helper chip. I'm game for most any sensor in the sub $20.00 range for one off projects.
For example I would like to purchase the MLX90614 Infrared Module's sensor if the SX code and schematic was available. Don’t take offence but it's a little pricy, for me to use, other than just to try it out and have another nifty one-off Parallax item. But in the same breath Parallax IS a business and they would not have made it this far without making a profit!
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Mike
Post Edited (Mike Cook) : 9/22/2008 10:55:11 PM GMT
I wasn't sure exactly how they worked. So, how can you tell what was detected? Do you get a ratio or something? In thinking of how I might use the sensor, I would probably want to trigger a different alarm for smoke than I would for a Propane leak. Or, are you saying that is just goes off when something is detected and you can't differentiate?
Sorry, I'm just not familiar with the detectors,
Dan