Arduino: Eh, just grab some pliers and bend the pins

The Something Awful Forums > Discussion > Hobbies, Crafts, & Houses > Arduino: Eh, just grab some pliers and bend the pins

SnoPuppy: Jun 15, 2005

valve posted:

I'm not massively familiar with the capabilities of the Arduino, but i'm looking to use one (or a similar microcontroller) for a project I have in mind. I need to read values for up to 64 ADCs (well initially i'll be building with just 8, but the final project will have 64), and then store these values and send them back out to the same number of DACs.

My plan is to drive it all serially, and develop it to have 8 chip selects, with each ADC and DAC IC having 8 devices within (the 8 chip selects bringing to total to the 64).

Is this something that the Arduino is capable of (even for the 8 channels), or do I need something with a lot more power?

(note: it's not an audio interface, it's reading data from a fader, and writing to a VCA for level control-- there is no audio)

First, you might have better luck posting this in the Electronics thread.

You said this isn't for audio - do you know the required sample rate and resolution?
What, specifically, are you trying to do?

There are parts that have 8 or more ADC channels, however you'd be hard pressed to find something similar on the DAC side. It's not really a question of processing power either, it's just the supported peripherals.
You should be able to get to 8 DAC channels if you use filtered PWM outputs, but that will depend on what the DAC is driving, sample rate/resolution, etc.

As far as the Arduino goes, you probably would need to look at the Mega, but you might also look at the MSP430 or Stellaris from TI.

You're not going to find a single part that has 64 ADC and 64 DAC/PWM channels though. If you need all your data in one place, and you really need 64 channels, you'd be better off with some external SPI/I2C converters.

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SnoPuppy: Jun 15, 2005

dyne posted:

What's the best way to step up the voltage output of the arduino? I'm making a tachometer frequency converter for my car. I put a 6 cylinder engine in my previously 4 cylinder car, and am using the arduino to cut the 6 cylinder engine tach signal frequency by 2/3 so it reads correctly on the 4 cylinder tachometer.

The tachometer takes a square wave at ~12-14v (whatever the alternator is putting out) and doesn't really use any current. I already have the arduino set up to read the 6 cylinder tach signal and output a 5v square wave at the appropriate frequency, I just need to step up the voltage to 12-14v. I'm pretty inexperienced with circuits, and if someone could maybe make me a circuit diagram I'd really appreciate it.

edit: also, the frequency will be <500 Hz, if that matters that much.

Others have given good explanations as to what you need to do to buffer the signal, but I'm curious if you've tried just driving it directly with the 5V output from the Arduino.

Even though the existing signal is at 12-14V, it's possible that the tach will accept a TTL level signal (5V) directly.

edit:
Out of curiosity, how are you interfacing the 12-14V alternator signal to the arduino?

SnoPuppy fucked around with this message at 18:34 on May 22, 2013

# ¿ May 22, 2013 18:28

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