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Topic: multiplexing question (Read 1 time) previous topic - next topic

grapewizardusa

Still no luck! This is so weird. I've had nothing but success with the arduino so far, I don't get it!

Maybe I've connected something wrong? I've tried switching out all different kinds of connections. Even tested it out with multiple 4051's, as I ordered several of them.

per the pinout on the playground article, i connected pin 16 to the Arduino's +5V output, and pin 8 to ground. Pins 11,10,9 connected to 3 of the Arduino's digital outs, pin 3 connected to one of the analog ins. Double checked the pinout with the specific Texas Instruments 4051 that I'm using, and it's the same. Also tried connecting pins 6 and 7 (E and Vee) to ground.

Found that the 4051 seems to function the same regardless of whether the digital outs are connected-- it automatically lets the pot data pass through, no matter what input it's connected to.

Any help??

MikMo

The only advice i have right now is to try to ground all unused inputs on the 4051. some CMOS IC's have a problem with floating input pins.

I made a dual 4051 multiplexer with 16 slide pot's recently and had no problems.

tomek

maybe you can post a photo of your set up ??

(by the way pin 6 and 7 one the 4051 need to always connected to ground)

ha det bra
tomek

MikMo

Here's a picture of the PCB i made for the 16 pot multiplexer, before the IC's were put in the sockets, pin 1 on each 4051 is in the upper right corner of the sockets.

http://www.mikmo.dk/misc/mux-pcb.jpg

It's hard to see what is connected to what in the picture so:

4051 (1)

pins 6, 7, 8 to GND
pin 16 to 5V
pin 3 to Arduino analog input pin 0
pin 11 to Arduino digital pin 2
pin 10 to Arduino digital pin 3
pin 9 to Arduino digital pin 4
pot 1- 8 wiper to pins 13, 14, 15, 12, 1, 5, 2, 4


4051 (2)

pins 6, 7, 8 to GND
pin 16 to 5V
pin 3 to Arduino analog input pin 1

pin 11 to Arduino digital pin 2
pin 10 to Arduino digital pin 3
pin 9 to Arduino digital pin 4
pot 9 - 16 wiper to pins 13, 14, 15, 12, 1, 5, 2, 4

The code i use is based on the 4051 sample in the playground, i just changed variable names because i found those in the sample code sligthly confusing, and i changed it to work with two 4051 IC's

grapewizardusa

I have been so busy lately that I haven't had a chance to give it another go.

Thanks for all the input! you guys are so helpful

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