Pinpointing objects in a 3 foot radius

Hello everyone

I've got a bit of a project i'd like to attempt. But the major sticking point currently seems to be finding the right sensor for the job.

Essentially what I want to do is to be able to pin point down to an accuracy of 1mm, an object within a 3 foot radius of either one sensor or two sensors.

The difficulty is that both sensors have to be on the same plane as i'm intending to build a dart board scorer, that sits on top of the dartboard..and having wires dangling would just look messy.

Here are the options i've considered thus far

  1. Some sort of Kinect style system - drawback being if one dart is hidden behind another dart it has no way of knowing

  2. Li-dar - again similar issue, also very expensive

  3. Ultrasonic detectors? Would it be possible to do this with two ultrasonic detectors aimed diagonally across the board?

I don't want to re-wire the back of the dartboard with some sort of resistive mesh.

Thoughts please :slight_smile:

Do you really want to construct a dartboard of 3 feet diameter?

Piezos may be used to detect an dart impact, and to calculate the coordinates from the signal time shift.

Or use distinct segments (placed on foam rubber?), with an impact sensor/contact behind each one. Kind of a keyboard, with styled keys and surface...

Hi Dietrrich

Thanks for your reply...

I'd opted for a 3 ft diameter sensing range, so it could possibly detect ones that fall outside the board, However you are right...in reality it is only 1.5 ft

I'm not hugely in favour of a segmented dartboard type sensor array..

How would one achieve this by piezo?

The piezo approach is just an idea, inspired by e.g. earth/sea quake monitoring. The shock wave of an impact travels through the board to the piezos, at constant speed. From the time difference of the signals it should be possible to calculate the impact coordinates by triangulation.