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I bought a USB SDR-dongle a couple of years ago, primarily to monitor aircraft, and similar things. Running a simple sniffer, trying to identify all the things
by stevekemp 6y ago
I bought a USB SDR-dongle a couple of years ago, primarily to monitor aircraft, and similar things.
Running a simple sniffer, trying to identify all the things transmitting locally was pretty fascinating. Prior to buying this I had no idea that tyres transmitted data via radio-waves (is it obvious I don't drive?)
I setup some wireless temperature sensors which transmit over 433Mhz, but eventually abandoned them. It was just as good to sniff the temperature-reports the tyres in the carpark beneath my flat were transmitting!
- bjelkeman-again 6y agoWould you recommend a sniffer?
- sokoloff 6y agoI’ve used the very cheap RTL-SDR dongles sold as TV receivers. Ones I use (that work well) look like this: https://m.aliexpress.com/item/1005001815260665.html https://m.aliexpress.com/item/1005001815260665.html
- dtgriscom 6y agoFor those on laptops that were confused by the humongous images, buttons and font on this link, try this non-mobile link: https://aliexpress.com/item/1005001815260665.html https://aliexpress.com/item/1005001815260665.html
- stevekemp 6y agoWould I recommend it as being fun/useful? Yes. Would I recommend a specific model? I'm not too familiar to be honest. I want to aliexpress and picked the cheapest USB RTL-SDR dongle I could find. Paid €5 or so for it, with a tiny little antennae.
- h2odragon 6y agothe rtl-sdr.com v3 dongle is a good specific hardware model to seek for general purpose "i dont know what i want to do with this" use. there's others with other strengths when you get more specific.
- ufmace 6y agoWait the TPMs also send temperature reports? That's pretty cool. I wonder how many you could see with a decent receiver, if they interfere with each other at range, if you could get a solid temperature from a few dozen low-quality sensors etc.
- helge9210 6y ago>Wait the TPMs also send temperature reports? Tire pressure measurement doesn't make sense without temperature.
- throwaway201103 6y agoYep. pV=nRT. This is why if you are checking your tire pressure manually you should do it when the tire is cold, and not immediately after a drive. "Cold pressure" is how the vehicle manufacturer's recommended tire pressure is specified. You'll still get some seasonal variation in most temperate regions.
- ufmace 6y agoI get what you mean, and I haven't had a car in a while, but the last one I had, the TPM didn't seem to correct for temperature at all, and would flag all the tires as being low on first start on cold days. I would have thought it would be better and easier to do environment temp monitoring and some heuristics in the central controller rather than put a temp sensor on every TPM and add temp data to the transmission protocol. Ex expect lower pressures when the exterior temp is cold and the engine is cold, expect higher when the engine is hot, etc.
- gumby 6y agoWhat makes you think the pressure wasn’t low at start? After driving some distance your tyres will warm up and the pressure will increase.
- ufmace 6y agoThat's the point. It was low, but that should have been expected due to the low environmental temperature. The warning system should know that it will increase to the proper levels when the tires warm up some and should not request that I inflate them further.