Please help identifying a device.  - Page 1
Forum section: electronics / projects

author: calli
author_rank: Regular Contributor
timestamp: April 22, 2017, 03:34:58 pm
content: I found this device on the street, several cars did go over it.I checked resistance just something about 0.6Ohm, does not change with temperature as it seems.Diode test shows both poles are equivalent.Block is steel or nickel maybe, a magnet attaches to it. No reed contact.Plug is 2.3mm. Two poles.Wild guess: Some sort of antenna? Some inductive thing? But cable is not shielded...Your guess?Thanks,Carsten

author: isometrik
author_rank: Regular Contributor
timestamp: April 22, 2017, 04:14:06 pm
content: It might be a temperature sensor.I onced used a 10K? thermistor based temperature sensor that had a very similar case form factor. Seehttps://www.digikey.com/products/en?keywords=615-1082-NDSince your device has such a low resistance, could it be a thermocouple ? Try measuring the open circuit voltage while having the metal case at different temperatures.

author: chris_leyson
author_rank: Super Contributor
timestamp: April 22, 2017, 04:39:37 pm
content: Might be an induction loop pickup or maybe a proximity detector.

author: Twoflower
author_rank: Frequent Contributor
timestamp: April 22, 2017, 04:55:43 pm
content: Could be a reed contact for window/door open alarms. And yes there are NC reeds out there.I should read the full text first...

author: calli
author_rank: Regular Contributor
timestamp: April 22, 2017, 07:53:49 pm
content: 0VNo Termocouple.And I guess for all frequency/induction stuff one would use either symmetrically lines or at least shielding.Reed switch i guessed first, could be always close when broken, but I guess a reed would not be in a ferromagnetic case.Last resort would be to crack it open.Carsten

author: edpalmer42
author_rank: Super Contributor
timestamp: April 22, 2017, 07:58:34 pm
content: Bimetallic temperature switch? It's closed now, but if it gets too hot (or maybe too cold) it snaps open.Ed

author: SeanB
author_rank: Super Contributor
timestamp: April 22, 2017, 08:38:46 pm
content: rersistance is suspicious, check it is not just a diode in there, as it will be around 0.6V one way and open circuit the other. Likely a diode temperature sensor, meant to be plugged into some controller or the other for use in air temperature measurement.

author: Gyro
author_rank: Super Contributor
timestamp: April 22, 2017, 09:01:51 pm
content: Curious that something like that would have a consumer grade 2.3mm jack on the end, not what I would expect for an overtemperature switch. Maybe some sort of accelerometer or vibrating device/sounder?Just a though (but these days...), hopefully it's not something that does something nasty or dramatic if you put power through it!

author: bktemp
author_rank: Super Contributor
timestamp: April 22, 2017, 09:17:57 pm
content: Maybe a reed switch for a cheap window alarm sensor? Many of them are normally closed.The cable doesn't look heat resistant, so I doubt it is a overtemperature sensor. Consumer grade temperature sensors are typically NTCs in 1k-100k range.

author: Twoflower
author_rank: Frequent Contributor
timestamp: April 23, 2017, 08:07:51 am
content: One other try from my side: A position sensor (e.g. mercury switch)?

author: calli
author_rank: Regular Contributor
timestamp: April 23, 2017, 08:15:25 am
content: Bimetallic: Heated it with a torch up to about 70°C nothing.The resistance changes from 0.6Ohm to 0.8Ohm or such then....Diode Test does not show any diode type characteristcs.Orientation or accel does not change any resitance/continuityNext:- Check on Oszi component tester- check (how) for being a active component- send it dave as mailbag :-)- your idea?I am still hoping someone will recon this piece :-) Curiosity kills me...Carsten

author: calli
author_rank: Regular Contributor
timestamp: April 23, 2017, 08:25:27 am
content: Component tester shows a vertically line.Carsten

author: calli
author_rank: Regular Contributor
timestamp: May 04, 2017, 03:05:46 pm
content: Broke it open. Take "broke" literally. That was quite hard gunk (sp?!) inside.What I found and broke was something looking like a reed contact. Really.... In a magnetic hull?! Still confused about this device.Still could have been (grammar?) a bimetallic thingy. But Google does not find anything looking like a reed but beeing bimetallic.Carsten

author: JolyGoodDay
author_rank: Newbie
timestamp: May 05, 2017, 12:38:23 am
content: Looks like.Magnetic sensor, paired with a magnetic for a door/window/ect to detect closed/open state for a alarm system. Maybe missing its plastic housing that has screw mounts.Never seen a 3.5 connector on one before tho... I would consider it a bad idea.I can see it coming from a blister pack product at Walmart, labeled as "Easy Home Security" powered by 2 AA batteries with a piezo alarm.Then again what do I know.

author: fcb
author_rank: Super Contributor
timestamp: May 05, 2017, 11:49:31 am
content: Might be the sensor from one of those 'hotel door alarms' you used to be able to buy. How long is the cable?