Post by thread:[EE]: IR detectors

PICers, I find myself in need of a smallish IR detector, ie. not an imager. The one I'm using now is a shop-standard intruder alarm with Moire lens. It pulls around 15 mA and I think that's a bit too much from a battery supply. I guess what's needed is something that pulls a quiescent current <1mA . Any ideas/suggestions? Thankz if can advise - Debbie :) http://mobile.yahoo.com.au - Yahoo! Mobile - Check & compose your email via SMS on your Telstra or Vodafone mobile. -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

Debbie, I think DIY electronics sells a smallish PIR kit that draws about 1Ma from 5v. The PIR sensor doesn't draw anything, but the analog signal processor draws about a mA. --Bob At 06:45 AM 6/28/2003 +1000, you wrote: {Quote hidden}>PICers, >I find myself in need of a smallish IR detector, ie. not an imager. The >one I'm >using now is a shop-standard intruder alarm with Moire lens. It pulls >around 15 >mA and I think that's a bit too much from a battery supply. I guess what's >needed is something that pulls a quiescent current <1mA . > >Any ideas/suggestions? > >Thankz if can advise - Debbie :) > >http://mobile.yahoo.com.au - Yahoo! Mobile >- Check & compose your email via SMS on your Telstra or Vodafone mobile. > >-- >http://www.piclist.com hint: The list server can filter out subtopics >(like ads or off topics) for you. See http://www.piclist.com/#topics --------------- NOTICE 1. This account can accept email & attachments up to 10M in size. 2. Federal Monitors: At request of client, some attachments are encrypted. Please DO NOT delay traffic; please reply with credentials for password. -------------- -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

> 1Ma from 5v. The PIR sensor doesn't draw anything, but the analog signal > processor draws about a mA. Why would the PIR not draw anything ? It normally has a 10k load resistor and produces ~2V across it in quiescent conditions (the PIR has a FET in source follower configuration inside). That's 200uA to start with. Maybe there is a different kind of PIR ? Peter -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

You can try to modify the detector you have. Most of the current likely goes into a LED or relay. The one I played with draws only 5mA or so and it is very old. It uses 1xLM358 + 1xLM339. By replacing the chips with lower power ones you can reduce the power requirements. Peter -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

Try this little beauty http://www.mew-europe.com/ac/download/datasheet/sensor/napion_en.pdf -----Original Message----- From: pic microcontroller discussion list [spam_OUTPICLISTTakeThisOuTMITVMA.MIT.EDU]On Behalf Of Bob Axtell Sent: 27 June 2003 21:57 To: .....PICLISTKILLspam@spam@MITVMA.MIT.EDU Subject: Re: [EE]: IR detectors - low current? Debbie, I think DIY electronics sells a smallish PIR kit that draws about 1Ma from 5v. The PIR sensor doesn't draw anything, but the analog signal processor draws about a mA. --Bob At 06:45 AM 6/28/2003 +1000, you wrote: {Quote hidden}>PICers, >I find myself in need of a smallish IR detector, ie. not an imager. The >one I'm >using now is a shop-standard intruder alarm with Moire lens. It pulls >around 15 >mA and I think that's a bit too much from a battery supply. I guess what's >needed is something that pulls a quiescent current <1mA . > >Any ideas/suggestions? > >Thankz if can advise - Debbie :) > >http://mobile.yahoo.com.au - Yahoo! Mobile >- Check & compose your email via SMS on your Telstra or Vodafone mobile. > >-- >http://www.piclist.com hint: The list server can filter out subtopics >(like ads or off topics) for you. See http://www.piclist.com/#topics --------------- NOTICE 1. This account can accept email & attachments up to 10M in size. 2. Federal Monitors: At request of client, some attachments are encrypted. Please DO NOT delay traffic; please reply with credentials for password. -------------- -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

Odd. The RE200B uses a 47K pullup. --Boib At 12:02 PM 6/28/2003 +0300, you wrote: {Quote hidden}> > 1Ma from 5v. The PIR sensor doesn't draw anything, but the analog signal > > processor draws about a mA. > >Why would the PIR not draw anything ? It normally has a 10k load resistor >and produces ~2V across it in quiescent conditions (the PIR has a FET in >source follower configuration inside). That's 200uA to start with. Maybe >there is a different kind of PIR ? > >Peter > >-- >http://www.piclist.com hint: The PICList is archived three different >ways. See http://www.piclist.com/#archives for details. --------------- NOTICE 1. This account can accept email & attachments up to 10M in size. 2. Federal Monitors: At request of client, some attachments are encrypted. Please DO NOT delay traffic; please reply with credentials for password. -------------- -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

that's a good idea. maybe extract the sensor that's already in there & just use that? Debbie :) --- "Peter L. Peres" <plpKILLspamACTCOM.CO.IL> wrote: > You can try to modify the detector you have. Most of the current likely > goes into a LED or relay. The one I played with draws only 5mA or so and > it is very old. It uses 1xLM358 + 1xLM339. By replacing the chips with > lower power ones you can reduce the power requirements. > > Peter http://mobile.yahoo.com.au - Yahoo! Mobile - Check & compose your email via SMS on your Telstra or Vodafone mobile. -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

> hat's a good idea. maybe extract the sensor that's already in there & > just use that? If your quary is a red hot piece of metal a few inches away maybe. Else not. The output is in milivolts or less. How big are your animals, and how furry ? If very furry and small then PIR may not work at all. I've once seen IR pictures of seals and polar bears and all you can see is the breath around the head (the seals emit a little more then polar bears but when wet they can appear *colder* than the dry ice they are sitting on). Peter -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email .....listservKILLspam.....mitvma.mit.edu with SET PICList DIGEST in the body

It works for cats, dogs, even chickens. I use a radio PIR outside on the farm I say on. In S.Africa there are up to 1400 farmers murded a year, so security is very necessary. Animals are a big problem, generate false alarms. {Original Message removed}

Yeah, it would need amplification, that's 4 sure. I've noticed birds don't seem to emit much IR especialy from sideways where the wing blocks the body. the critters i'm after would come in a range of sizes, from say rabbit size up to dog size. they're mostly nocturnal so the SNR wrt bnackground IR is quite high. in winter anyway. :| Debbie :) PS: Err - u must be running out of farmers in SA at that rate?? --- gtyler <EraseMEgtylerspam_OUTTakeThisOuTDRUMMOND.ORG.ZA> wrote: > It works for cats, dogs, even chickens. I use a radio PIR outside on the > farm I say on. In S.Africa there are up to 1400 farmers murded a year, so > security is very necessary. Animals are a big problem, generate false > alarms. > > {Original Message removed}

> Yeah, it would need amplification, that's 4 sure. I've noticed birds > don't seem to emit much IR ..................SNR wrt background IR is > quite high in winter Have you Googled for something like +murata +PIR ? A project of a couple of years ago involved using Murata piezo sensors to detect people in a room 10m away with a battery- operated micro. The sensors on their own are pretty limited to a lot of movement under metre but adding a Fresnel lens makes a huge difference. Amplification is TLC271s at low frequency/ low current setting. As the unit had a timeout period after detection the V+ for the amps was supplied by a PIC pin. From memory the PIR part of the circuit used around 20uA. The range that needs boosting is at most a few Hz. I found that the simple circuit used was fairly insensitive to air movements. Common security light circuits I looked at were more complex and usually based around a quad amp like an LM324. Their complexity helps to prevent false triggering, but in our app that wasn't too much of an issue so we just went with amplication. PIRs themselves are pretty good filters anyway. The Fresnel lenses were got from a local alarm supplier. As only a narrow horizontal band of detection was needed it was found that using just a 15mm strip from the middle of the (originally 50x50) lens was sufficient. Be aware that lenses are available for particular applications - eg curtain, long range, short range etc - and you may need to optimise. And not all plastics are transparent to PIR so watch out for that. Some lenses found weren't intended for PIR I would expect that small furry animals don't emit much heat. Fur is, after all, a very good insulator. Have you considered something more sophisticated, eg a motion detector based around a camera ? A webcam and an IR spotlight would do. By comparing frames it should be quite easy (on paper) to detect a new object. Plus you get a picture of it. The resolution of the comparison could possibly be used as a filter to focus on a particular size of aminal. eg http://home.earthlink.net/~apendragn/gbcam/ or Google for "artificial retina" -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listservspam_OUTmitvma.mit.edu with SET PICList DIGEST in the body

part 1 330 bytes content-type:text/plain; (decoded 7bit) PS meant to include the PIR amp circuit. It has two PIRs so as to cover (ISTR) about 160 degrees horizontally. The outputs are ORed into b0 to wake the PIC -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email @spam@listservKILLspammitvma.mit.edu with SET PICList DIGEST in the body part 2 4268 bytes content-type:image/gif; (decode) part 3 2 bytes -

Studying a TV image capture works. Barcodes can be extracted from PAL or VGA images pretty easily once the software can determine their orientation. The big problem with that is that image arrays draw a lot of current, and they have to be on all the time.. Not workable for battery systems. There's more to PIR (long wave, i.e. heat radiation) than meets the eye. In an outdoor setting, for example, a very sensitive PIR detector can easily pick up the steady radiation of the BIG BANG, and anything that interrupts that radiation, even if cold, will be detected. That's not well know, but is the reason persons and animals with heavy fur can be detected. --Bob At 10:31 AM 6/30/2003 +1200, you wrote: {Quote hidden}> > Yeah, it would need amplification, that's 4 sure. I've noticed birds > > don't seem to emit much IR ..................SNR wrt background IR is > > quite high in winter > >Have you Googled for something like +murata +PIR ? > >A project of a couple of years ago involved using Murata piezo >sensors to detect people in a room 10m away with a battery- >operated micro. The sensors on their own are pretty limited to >a lot of movement under metre but adding a Fresnel lens makes >a huge difference. Amplification is TLC271s at low frequency/ >low current setting. As the unit had a timeout period after detection >the V+ for the amps was supplied by a PIC pin. From memory the >PIR part of the circuit used around 20uA. The range that needs >boosting is at most a few Hz. I found that the simple circuit used >was fairly insensitive to air movements. Common security light >circuits I looked at were more complex and usually based around >a quad amp like an LM324. Their complexity helps to prevent >false triggering, but in our app that wasn't too much of an issue >so we just went with amplication. PIRs themselves are pretty good >filters anyway. The Fresnel lenses were got from a local alarm >supplier. As only a narrow horizontal band of detection was >needed it was found that using just a 15mm strip from the middle >of the (originally 50x50) lens was sufficient. Be aware that lenses >are available for particular applications - eg curtain, long range, >short range etc - and you may need to optimise. And not all plastics >are transparent to PIR so watch out for that. Some lenses found >weren't intended for PIR > >I would expect that small furry animals don't emit much heat. Fur >is, after all, a very good insulator. Have you considered something >more sophisticated, eg a motion detector based around a camera ? >A webcam and an IR spotlight would do. By comparing frames it >should be quite easy (on paper) to detect a new object. Plus you >get a picture of it. The resolution of the comparison could possibly >be used as a filter to focus on a particular size of aminal. eg > >http://home.earthlink.net/~apendragn/gbcam/ > >or Google for "artificial retina" > >-- >http://www.piclist.com#nomail Going offline? Don't AutoReply us! >email KILLspamlistservKILLspammitvma.mit.edu with SET PICList DIGEST in the body --------------- NOTICE 1. This account can accept email & attachments up to 10M in size. 2. Federal Monitors: At request of client, some attachments are encrypted. Please DO NOT delay traffic; please reply with credentials for password. -------------- -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email RemoveMElistservTakeThisOuTmitvma.mit.edu with SET PICList DIGEST in the body