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Topic: Multiplexing 30 FSRs (Read 1 time) previous topic - next topic

justextreme

Hi everyone,
I'm currently doing a project at the university and using arduino uno with MaxMSP software in order to work with sound (to be exact: maxuino software for maxmsp 5).
It's a requirement of the project to be able to read data from 30 Analog Inputs(to be exact: FSRs), but arduino board has got only 6.
I got few multiplexers, to be exact: cd4076be, with the datasheet/documentation available here: http://www.ti.com/lit/ds/symlink/cd4076b.pdf (i got few of these, so as long as i'll be able to multiplex atleast a little bit - i'll multiplex even further, so i just need a basic guide for simple multiplexing)
I'm not able to understand thought, how to use the multiplexer in order to receive the data from more FSRs, i tried to connect it in different ways, but not successfully.

I'll be really thankful if some1 would help me out with this thing, since i have no idea how to do this thing.
Furthermore - please don't explain me how it fully works, i just need the information, regarding exactly where i should connect everyting, lets say if we have 4 analog inputs > 1 arduino analog input, ground, 5v and if required few digital outputs.

Furthermore, it's not hell of a big problem for me to get few more arduinos, would it be possible to use all 4 of my usb ports and 4x arduinos to get 6x4, thus 24 analogin inputs that way? p.s. at the same time, on a laptop.

fungus

If we do your project for you do we get your University degree?


No, I don't answer questions sent in private messages (but I do accept thank-you notes...)

justextreme

#2
Apr 29, 2013, 12:12 pm Last Edit: Apr 29, 2013, 12:16 pm by justextreme Reason: 1
It's not part of our knowledge to know how multiplexing works, i already wrote an e-mail to teacher so she'd be able to help us, on the other hand i thought i might find some friendly people here who know this stuff and might speed up the process. I'm sorry to tell, but it seems like you are not one of them.
p.s. stop offtop, if you can possibly help and donate few minutes of your life - i'd be really thankful, if you can't - just don't waste my/your time on writing useless messages, thank you.

fungus

What have you tried doing so far...?

No, I don't answer questions sent in private messages (but I do accept thank-you notes...)

Magician

http://playground.arduino.cc//Main/InterfacingWithHardware#multiplin

AlxDroidDev

Another option is not to read analog inputs, but read them digitally from three 10-channel ADCs, such as this one:

http://www.hobbytronics.co.uk/adc-i2c-slave

You'll need 3 of these, each one in a i2c address. Since they'll all be in a single i2c chain, all you'll need for the 30 analog inputs are 2 arduino pins (namely the SDA and SCL pins). As you've already figured out, your FSRs will be connected to the ADCs.

8-channel ADCs are easier to find, but in that case you'll need 4 of them. If possible, go for parts that can be chained (like i2c), so you don't use too many arduino pins just to connect the ADCs.

Some of my projects:
Shield for DS1337+, DS1624 and AT24C1024B (RTC, temp & mem): http://forum.arduino.cc/index.php/topic,126197.0.html
CHDK Camera remote shutter (BT, IR, USB): http://forum.arduino.cc/index.php?topic=295377.0

justextreme

I had a wrong datasheet/documentation, teacher has sent me the right one - and i succeeded in making multiplex, so now from 1 analog input i have 16 :) Thank you for those who tried to help me, for your time :)

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