Do you have line of sight from any allowable vantage points for all six outdoor units? (The power meter is a great idea) On 2 June 2017 at 12:47, Forrest Christian (List Account) < lists@packetflux.com> wrote: > I have a semi-low-tech idea for you: > > Something like the following, potted in some hot glue with a magnet stuck > on the side of each unit.... > > http://www.instructables.com/id/The-Ultimate-FM-Transmitter/ > > You could also waterproof with a ziploc bag, etc. > > These are available in various forms, kits, finished, etc.... I'd > probably design such that the microphone element is against the metal of > the unit. > > > On Thu, Jun 1, 2017 at 4:10 PM, Neil wrote: > > > Hi all, > > > > My neighbor and I are trying to find the source of a noise that's > > bugging us, which is from one of 6 A/C units on the roof above us. It's > > a periodic hum, plus a noticeable rattle when the thermostat switches > > off that unit. I've asked the A/C service guy to check and he says it > > would take quite some time to monitor for that. > > > > I know it's not my A/C unit as the hum/rattle does not coincide with th= e > > operation of my A/C. Same for my neighbor. One of the other possible > > residents is gone for 11+ months each year, and I doubt he'd leave that > > unit on all year. So that leaves 3 units. Coordinating with the other > > residents has been difficult, so I'm thinking I can come up with some > > sensing device that can remotely alert me as to which unit is switching > > on/off at any time. The other complication is that I am not allowed to > > be on the roof (insured A/C repair persons only), but I can just > > probably just deploy the sensor with a drone perhaps. > > > > So... what's an easy way to sense this? Getting a current sensor aroun= d > > the A/C lines will be difficult, but a vibration sensor magnetically > > attached to the side of the unit should be simple. I'd think I can > > create a small circuit with an accelerometer and a processor (perhaps a= n > > Arduino), then add some type of wireless transmitter, and a power > > source. BTW, power really only needs to last a few days. And then > > there's enclosing/waterproofing. > > > > Alternately, I'm wondering if I can mount a wireless camera up there > > facing all 6 units and vertically attach a stick to the side of each > > unit and see which one rattles when the A/C goes off. Assuming the > > rattle is enough to visually move the stick. I'm fine with low-tech. > > Any other ideas. > > > > I really don't have a lot of time for custom circuitry right now. There > > has to be a simpler way. Is there some pre-made device I can use to do > > this, or most of this? > > > > Cheers, > > -Neil. > > > > -- > > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > > View/change your membership options at > > http://mailman.mit.edu/mailman/listinfo/piclist > > > > > > -- > *Forrest Christian* *CEO**, PacketFlux Technologies, Inc.* > Tel: 406-449-3345 | Address: 3577 Countryside Road, Helena, MT 59602 > forrestc@imach.com | http://www.packetflux.com > > > -- > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .