More Analog Inputs?

Forum 2005-2010 (read only) Hardware Interfacing
1

Hello:

I was wondering if anyone knows of a shield or accessory that will give me more analog inputs into an Arduino. I find myself needing from 6 to 9 of them.

I was just wondering if there was basically an AD shield that will do the same process as the analog inputs in the Arduino shield and then pass them over to the digital inputs, I could save myself having to buy a Mega that also has a lot more digital inputs I don't need. :-/

Any ideas?

Thanks!

2

There are a few shields that give you more analogue IPs, offhand I can't think of a single one though :(, have a look on shieldlist.org.

EDIT: Just found one http://store.curiousinventor.com/stribe-multiplexer-arduino-shield.html but there are more around.

Rob

3

"accessory" - go to analogdevices.com or maxim-ic.com and request samples of an analog mux and an a/d converter. write a little bit of code to select the analog input you want to read, digitize it, and read it in serially with SPI or shift in or whatever based on the chip you select.

Or try something like this
http://www.vellemanusa.com/us/enu/product/view/?id=351127
select a relay and feed into the arduino a/d converter.
Search around for a good price.

4

It's easy to make your own with an analogue multiplexer.
See this project:-
http://www.thebox.myzen.co.uk/Hardware/MIDI_Footsteps.html

5

Well I actually think (and I'm amazed this hasn't occured to me before), is instead of multiplexing it, getting a shield with more 10-bit ADCs on them, like the ones in the actual Arduino, and just go into the Digital Inputs. Would that work? I'm not very savvy on the digital side of things (I'm learning though!)

Cheers for all your answers, some of the stuff I've found is incredible!

6

getting a shield with more 10-bit ADCs on them

Is there such a shield?

If so you'll have to control the ADC with i2c or SPI which, while not hard, will be more difficult than simply switching a MUX, so I see little benefit unless you need high speed and the shield can be used to offload some processing.

Rob

7

ike the ones in the actual Arduino,

Just to point out that there is only one A/D in an arduino. It has a built in multiplexer in front of it so that it looks like there are six but in fact there is only one.

8

Oh, I did not know that!
I'll give a mux a try, they look like a good idea though. I understand the difficulties with the ADC Shield.

Thanks =)