Hi all, I have been playing around with Arduinos for a while but still have a lot to learn and I could use some advice for my next project. I need a very high sample rate for an two analog read inputs, around 20 Mhz. Is this possible with an ATMega, or preferably an ATTiny85?
I'm trying to measure the speed of a bullet. I will have two IR detectors at a known distance with IR LEDs on the other opposite side, the bullet will travel through and interrupt the light beam. Is there any way to measure this at that frequency? I am totally open to any options. Arduino is what I'm familiar with but I'm more than happy to research some other controllers if that is what I need to do.
No. The maximum for AVR chips is about 1mHz.
QuoteNo. The maximum for AVR chips is about 1mHz.No, fungus, it is much higher than that.
Is this possible with an ATMega, or preferably an ATTiny85?
@OP, an analogue read is not what you want.Some back of a beer-mat calculations.A bullet at Mach 1, or about 340ms-1, travels about one third of a millimetre in one microsecond.An Arduino could execute up to 16 instructions in that time.What are your accuracy constraints?
QuoteIs this possible with an ATMega, or preferably an ATTiny85?It i s entirely possible on a 200Mhz avr.
I don't know why you're hanging onto analogue reads.The bullet is either there or it isn't.You'll almost certainly need some signal conditioning external to the processor, but taking this kind of stuff out of the lab isn't a good idea (it is, after all, packing a lot of punch, even if it is very light!).I don't imagine commercial, enthusiast-grade chronos go this high, simply because such velocities are way out of the ordinary (about 50% greater than what you'd expect for a Barrett?)