Liza Sarychev said:
Hi 1rel! Thank you for your response.
I cutout the flat part of a paper plate, fold it over on itself and glue foils to it, so that when the arrow pierces, it connects the two pieces together and closes the circuit.
Probably, it will be difficult to make this very reliable/consistent, because you never know if the the foils really make a good contact for every hit. You could try to use an https://www.arduino.cc/en/Reference/AttachInterruptinstead of polling the pin (via ADC or digital), that might catch the change in voltage on the pin when the arrow hit and raises/lowers the voltage for a short amount of time.
https://learn.sparkfun.com/tutorials/logic-levels ... using a pullup or pulldown resistor, and a capacitor to dampen/"extend" the spike - some kind of
debounce circuit (it will certainly never give you a stable good contact, so a simple, repeated digitalRead() (polling) on the pin will possibly not work).
There's also an interesting material called
velostat, that could help to make some kind of pressure sensor. Or to make it more conductive and reusable, you might use conductive fabric/textiles, and a conductive/metal arrow head.
These would have to be replaced every shot. So far I've tried to connect the strobe, a resistor, and the switch in series hooked up to 5V on the Arduino and nothing is happening.
When you'd like to work with the microcontroller/arduino, just print out some messages via serial to see what's happening. I'd leave the strobe away for now, to make the detection work first.
Should I be doing something to protect the Arduino from the high voltage spike of the strobe?
How do you trigger the strobe, with some kind of relay? I don't know much about that part...
I have thought about an induction target. I will look into the hall sensor + magnet scenario and the possibility of measuring a difference in capacitance. Because the arrow pierces the target (and 4 inches of foam behind it), an impact sensor wouldn't work I think. For this first round, I want to figure out how to get it to work the simplest way I can and then I'll experiment with different methods of triggering the strobe.
After thinking about it for a bit, I guess that it depends on the size and accuracy you need for the detector.
The infrared LED + photo diode/transistor solution might work, when the arrow only triggers in one tiny spot (precise hit).
On the other hand, with the piezo vibration detector idea, the problem would be that it would trigger also when the arrow hits the target just somewhere you don't want it to (it might be possible to hang the target on some springs, or dampen the vibration it with foam...).
Both of those solutions would not be that hard to get working, I think.
I am looking at using long cables to hook all of them to the central arduino. Is there a way to do this without an arduino?
Anorlunda mentioned, that you could leave the (tiny) computer away altogether, and try to detect it with an (analog) cirucit (in case of the piezo/IR solution, it would probably involve OpAmps as voltage amplifier, peak detector and schmitt trigger of some kind - I've once tried something like that for a pluck detector of a string...).
Or you can also use a different microcontroller (like the ATtiny85 for example, which is also Arduino compatible, but smaller and much cheaper, or some ARM controller for more speed/advanced features like cap sense) to get rid of the cost of the Arduino...
