54 a2d channels 0-5v

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I am looking for a way to monitor 54 a2d channels 0-5v. To begin with I thought about using an Atmega8 or 16 and some standalone adc modules like tlc1543 or adc0838. But with multiple adc's this becomes very complex, quickly. Maybe, I should use 5 attiny461 modules instead as they are possibly more flexible to use and I am more familiar with their architecture?

I only have experience with adc within the 1 avr module running by itself but in this project I will need to send all the values from the various channels to a master connected to an LCD. So I am not sure of the best way to proceed in terms of communicating protocols and modules. Any help would be appreciated!

Lachlan

What we need to learn,
we learn by doing.

Last Edited: Tue. Sep 20, 2011 - 11:41 AM
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Just use analog multiplexers and any AVR with built-in ADC.

Warning: Grumpy Old Chuff. Reading this post may severely damage your mental health.

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How often do you need to sample each channel?

(IOW could you use an external analog multiplexer?)

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no real speed requirement. Each channel only has to return a value once a second so 1000/54 18 to 20 ms per channel

Lachlan

What we need to learn,
we learn by doing.

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It does however need to be precise to 0.1v. Do you have a recommendation for a specific analog multiplexer and is it difficult to chain them together?

Lachlan

What we need to learn,
we learn by doing.

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cmos 4051 is a cheap multiplexer. Is it hard? Not realy, the 4051 is much like a 8 way rotary swotch except you give it three binary bits to select the input. With 8 analog inputs on the AVR and a 4051 on each, that gives you 64 analog inputs. Just three port bits to control the 4051s.
job done.

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That sounds great and exactly what I am looking for. Thankyou

Lachlan

What we need to learn,
we learn by doing.

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Quote:

rotary swotch

Would that be a fashionable timepiece with real hands? Ooops, no, that would be a "rotary Swatch".

You can put lipstick on a pig, but it is still a pig.

I've never met a pig I didn't like, as long as you have some salt and pepper.