Trilateration Based Nerf Target


Active member

I've been thinking about making a nerf targetboard for my son that uses 4 piezo sensors to wait until a analogue value increases over a threshold and then calculate the tdoa to get the position.

I've done a few tests with a 350x350 MDF board with each sensor 145mm from the centre point.

Is this possible to find the target hit point on a small area like this, or is there too much error to take into account when you are down to 100-500 microseconds between sensor readings? Im using a t4 with all sensors on analogread, but I'm starting to think it might not be feasible.

Well the velocity of sound in MDF is apparently about 2500m/s, so a time difference of 10µs would be about 25mm, so I'd suggest sampling at that sort of rate, ie 100kSPS for each sensor. Some experimentation with a 2 or 4 channel 'scope would be very useful too, to see what sort of signal waveform you get.
You first need to characterize the signal you are going to work with I think... Sampling rate depends on that.