I have not looked at the resolution required but @drjohsmith has done a preliminary estimation.

I would imagine that an interrupt from an IR emitter to all slave MCUs should do the trick.

 

All you need is fit the skaves to signak the naster as soon as the detect t

Your thought was my initial reasoning, but I came under the impression that using I2C, the slaves could only send data upon request by the master. So I decided, based upon that, to have the slaves do some calculations while they were waiting for the master's request. I was trying to be efficient. What Protocol would be the lowest latency for this?

Why do you even need the slaves? You could have the two microphones connected to a single micro.

Bob

 

All you need is fit the skaves to signak the naster as soon as the detect t

Why do you even need the slaves? You could have the two microphones connected to a single micro.

Bob

That might work with an analog RF link.

 

All you need is fit the skaves to signak the naster as soon as the detect t

Why do you even need the slaves? You could have the two microphones connected to a single micro.

Bob

Because the MCU's can only process one instruction at a time. I ran into time bottlenecks 'for lack of a better term." By the time digitalRead() processes for 3 or more sensors, the time of detection for each sensor is farther from the real time event. Unless there is a technique i should follow to defeat or mitigate these skewed detections, I don't see how it will work. I have limited knowledge on MCU's so if I'm missing something please fill me in.

 

You could still put three MCUs on one board and clock them together.

 

Your thought was my initial reasoning, but I came under the impression that using I2C, the slaves could only send data upon request by the master. So I decided, based upon that, to have the slaves do some calculations while they were waiting for the master's request. I was trying to be efficient. What Protocol would be the lowest latency for this?

How do you plan to interconnect these devices, physically?

 

How do you plan to interconnect these devices, physically?

Shielded twisted pair. What would you recommend?

 

That might work with an analog RF link.

Or wired.
Bob

 

You could still put three MCUs on one board and clock them together.

Interesting. Please elaborate.

 

How far apart do the microphones need to be placed?

 

How far apart do the microphones need to be placed?

they're all within a 25cm radius.

 

they're all within a 25cm radius.

In that case I would go with my original design with keeping the MCU clocks in sync.

 

If you insist on 3 micros, all you need is a wire from each slave to interrupt the master when the sound is detected. No synchronization necessary.

Bob

 

If you insist on 3 micros, all you need is a wire from each slave to interrupt the master when the sound is detected. No synchronization necessary.

Bob

So, when slaves detect sound, send high to master. Master notes time of pin reads and calculates the solution. Am i following you? Maybe I am splitting hairs but that would add one additional loop to detect the second sensors high. This would add maybe 20 microseconds. But would it really matter. Maybe some error correction for the elapsed time of the processes? Hmm.

 

So, when slaves detect sound, send high to master. Master notes time of pin reads and calculates the solution. Am i following you? Maybe I am splitting hairs but that would add one additional loop to detect the second sensors high. This would add maybe 20 microseconds. But would it really matter. Maybe some error correction for the elapsed time of the processes? Hmm.

If you have time critical needs, as you do, you would use interrupts, not polling. You could also potentially use FreeRTOS rather than trying to manage the timing and synchronization yourself.

 

If you have time critical needs, as you do, you would use interrupts, not polling. You could also potentially use FreeRTOS rather than trying to manage the timing and synchronization yourself.

Ah yes, RTOS. Just, as of now, it is not compatible with my particular MCU's. Already tried.

 

If only there existed a legitimate and reasonably priced quad core microcontroller. No problem.

 

I would like to thank everyone for their gracious input up to this point. This is a great forum. The wife is calling I'll check this thread again later. Cheers!

 

The goal of the project is to experiment with detecting the location of a gunshot, either through triangulation, trilateration, or some geometrical combination thereof and to accomplish this by using the light and sound of the shots fired.

Use MC contains INPUT CAPTURE WITH DEDICATED TIMER modules, like PIC24FJ256GA110.
May be this post will useful to you:
https://forum.allaboutcircuits.com/...ctiles-for-target-scoring.177421/post-1609229

 

Yes, input capture is perfect for this. Allows you to get the time of a signal transition with 0 latency.

Bob