Hey, Ive had this idea on my mind for a while now, to measure the singal strength to determine distance. I have a few 433MHz SYN115 SYN480R RF modules so I can use varying lengths of antenna.
Let me know if this is completely unrealistic.
Here are a few images of the boards because there doesn't seem to be many images online.
1.
A lot of people think this is a simple easy way of measuring distance, but its not.
Any variation in antenna angle, or objects in the path between TX and RX can cause very large variations in signal strength and thus the measured 'distance'.
If you want to experiment, there are quite a few SPI based UHF radio modules (not the ones you pictured) that will allow you to read the received signal strength (RSSI) directly as a digital number and also allow you to vary the power.
Unless you have a way to measure the radiated power from your device and keep it the same as you change antennas, the project is hopeless. Anything different than a 1/4 wave antenna will automatically reduce the radiated power, so you will have to increase the transmitted power to make up for the loss at the antenna.
thanks for the insight. I might try "Acoustic location". I did some math and I think I'm wrong. sound is 1100 feet/second or 335280 mm/second so If I want 1mm accuracy I would only need a clock to run at 335280Hz or 335.28KHz?
srnet mentions a way. but I think I'm going to try something else since it seems more straight forward to go with sound XD. thanks
Maybe if you describe what the project actually is you might get some suggestions.
Measuring distance in what context ?
so I'm thinking I can track 3d location in my room for VR. if its sound based it would be at a frequency outside of human hearing.
Does the room have non-sound-reflecting surfaces?
No but im willing to work through sound reflextions, obstructions or other noise cuz in theory a reflection sounds different and often more delayed than the source.
ok Ill close the topic I can add a link if I make a new one for the sound thing.
so heres my idea play a tone of 120 Hz pulses in a frequency that cant be heard and measure the delay between spikes and do triangulation. the corners of a room looks really similar to those photo reflectors, wouldn't the corner reflect any sound that isn't in the direct corner? I'd just have to make sure all the mics are synced but I could do that with some GPS modules for time.
You are introducing an obvious ambiguity. You might be receiving pulse 2 on one mike and pulse 3 on the other. How will you know?
The group of ticks that are closest? If it's at 60 or 120 hertz I'm sure that's possible. As in if there's a long enough pause you can assume there's a new pulse.
The ticks will be in referance to an atomicly accurate clock like a gps or idk, what other clocks sync to an an atomicly accurate clock?
(Optionally) I'm willing to run long cables
It is possible to measure (X,Y,Z) positions for one tag, in a room up to about 20x20 m^2, to about +/- 10 cm accuracy using UWB DW1000 6 GHz radio modules.
The MakerFabs ESP32 UWB boards are a good option. You will need 3 anchors and 1 tag to record (X, Y) positions, or 4 anchors for (X, Y, Z). Code and examples here.
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