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Topic: How to feed back 16 analog signals into an Arduino Nano (Read 131 times) previous topic - next topic

germanviscuso

Hi!

I'm using a few I2C 4-channel DAC ICs (MCP4728) to generate 16 analog signals (signals go from 0 to 5V but are analog, not digital). Let's call them DAC[0-15].
I control these via I2C from an Arduino Nano SDA and SCL lines.
Now I would like to feed back those analog signals to the Arduino ADC ports to do an analog to digital conversion. Nano has 8 ADC lines, A[0-7], but I have 16 signals.
What IC can I use to switch between DAC[0-7] and DAC[8-15] and control it from the Arduino?
I looked into multiplexers but they handle only one line on one side of the chip (an I want to leverage the multiple ADC lines of the Nano).

Thanks in advance!

gardner

Something like an Analog Devices ADG508F analogue switch is going to be your friend.  The Arduino Nano ATMEGA MCU only really has one ADC anyway, with an analog MUX in front of it.  Another couple of 8:1 muxes will get you 16 inputs.

germanviscuso

Ok thanks!

So maybe instead of leveraging all A0-7 lines I could use a  CD74HC4067 (Texas Instruments) http://www.ti.com/product/cd74hc4067 to multiplex the 16 analog signals to Arduino's A0 ADC?

Best.

gardner

Yes, exactly.  Thanks for the pointer to the TI MUX.  I could only find 8:1 ones when I looked on Mouser.


zoomkat


Yes, exactly.  Thanks for the pointer to the TI MUX.  I could only find 8:1 ones when I looked on Mouser.


You can use a 4051 chip to control up to eight other 4051 chips fairly easily. Some schematics below.

https://www.google.com/search?q=4051+arduino&num=100&as_qdr=all&tbm=isch&tbo=u&source=univ&sa=X&ei=2XZAVMW9GMyQNuatgCg&ved=0CDQQsAQ&biw=1136&bih=627
Google forum search: Use Google Advanced Search and use Http://forum.arduino.cc/index in the "site or domain:" box.

germanviscuso

Just realized that the I2C lines occupy two of the ADC pins so it wasn't possible to use the 8 ADC pins anyway!

CrossRoads

Use a couple of SPI 8-channel ADCs then.
http://www.digikey.com/product-detail/en/MCP3208-CI%2FP/MCP3208-CI%2FP-ND/305928
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.


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