3 ms·

You could do this with much less than an RPi. I would recommend using an AVR or better yet a 555 timer if all you need is an 80KHz signal. Let me know if you

You could do this with much less than an RPi. I would recommend using an AVR or better yet a 555 timer if all you need is an 80KHz signal. Let me know if you want help with this I'm looking for projects like this or something much more complicated.

IshKebab 11y ago
I wouldn't recommend an AVR. That is outdated technology. Even Atmel mostly makes ARM microcontrollers now (and they are much nicer than their AVR ones).
- niccl 11y ago
  horses for courses. If you want a small microcontroller that has a very simple IO model then avr is great, and if you use something like an attiny they're cheap as ... chips.
  - zokier 11y ago
    At small scale the price difference is pretty meaningless or even non-existent. For example right now the cheapest AVR at quantity of 10 costs $0.837, while cheapest ARM is $0.714. (prices checked from digikey)
- mrob 11y ago
  AVRs are simple and reliable. You can read the whole datasheet and understand everything with much less effort than modern ARM MCUs. They've been around long enough that I have a lot of confidence in them. They're electrically more robust than most modern chips so they're hard to accidentally damage. There's a lot of community support available because of the popularity of Arduinos. Many tasks don't need anything more powerful. I think it would be foolish to discard AVRs as obsolete just because they're old.
- jcoffland 11y ago
  AVRs are far from outdated. The AtXmega series is very powerful. It includes modern features such as DMA transfers. AVR chips are much easier to work with than ARM for certain applications. They are also lower power and cheaper. The OPs application would be significantly easier to implement on an AVR. On the RPi you would have to write a Linux kernel driver and deal with real-time issues. In the AVR you would create a few interrupt handlers and be done.
cmrdporcupine 11y ago
Or a Parallax Propeller
Aeolos 11y ago
That's true, the reason I mentioned the RPi was because I happen to have one lying around. (Actually, I seem to remember there are a couple of AVR development boards lying around in the lab, so these might be worth a look.) My project involves generating two analogue signals to drive a mirror (a sin wave on the x-axis and a staircase pattern on the y-axis), and a synchronized digital trigger signal for the camera. There are a number of configuration options that make this slightly more interesting than it looks at first (frequency, number of sin periods per staircase step, duty cycle and number of triggers per sin). An implementation of this on a NI DAQ took the better part of a day and an implementation on a FPGA took roughly two weeks (mostly spent on familiarizing with the tools and communicating settings from the host.) I actually think an implementation on the RPi would be simpler than either, including wiring up simple DAQ.
- jcoffland 11y ago
  I think you will run into real-time performance problems on the RPi.

IshKebab 11y ago

I wouldn't recommend an AVR. That is outdated technology. Even Atmel mostly makes ARM microcontrollers now (and they are much nicer than their AVR ones).

niccl 11y ago
horses for courses. If you want a small microcontroller that has a very simple IO model then avr is great, and if you use something like an attiny they're cheap as ... chips.
- zokier 11y ago
  At small scale the price difference is pretty meaningless or even non-existent. For example right now the cheapest AVR at quantity of 10 costs $0.837, while cheapest ARM is $0.714. (prices checked from digikey)
mrob 11y ago
AVRs are simple and reliable. You can read the whole datasheet and understand everything with much less effort than modern ARM MCUs. They've been around long enough that I have a lot of confidence in them. They're electrically more robust than most modern chips so they're hard to accidentally damage. There's a lot of community support available because of the popularity of Arduinos. Many tasks don't need anything more powerful. I think it would be foolish to discard AVRs as obsolete just because they're old.
jcoffland 11y ago
AVRs are far from outdated. The AtXmega series is very powerful. It includes modern features such as DMA transfers. AVR chips are much easier to work with than ARM for certain applications. They are also lower power and cheaper. The OPs application would be significantly easier to implement on an AVR. On the RPi you would have to write a Linux kernel driver and deal with real-time issues. In the AVR you would create a few interrupt handlers and be done.

cmrdporcupine 11y ago

Or a Parallax Propeller

Aeolos 11y ago

That's true, the reason I mentioned the RPi was because I happen to have one lying around. (Actually, I seem to remember there are a couple of AVR development boards lying around in the lab, so these might be worth a look.) My project involves generating two analogue signals to drive a mirror (a sin wave on the x-axis and a staircase pattern on the y-axis), and a synchronized digital trigger signal for the camera. There are a number of configuration options that make this slightly more interesting than it looks at first (frequency, number of sin periods per staircase step, duty cycle and number of triggers per sin). An implementation of this on a NI DAQ took the better part of a day and an implementation on a FPGA took roughly two weeks (mostly spent on familiarizing with the tools and communicating settings from the host.) I actually think an implementation on the RPi would be simpler than either, including wiring up simple DAQ.

jcoffland 11y ago
I think you will run into real-time performance problems on the RPi.