hi,

I want to send 1 analog output which is always 'high'. Then I want 8 analog inputs and check on which of the 8 analog inputs the 'high' signal returns...

But the mbed doesn't have that many analog inputs, so I guess I have to use another method.

Can anyone tell me which other method and how?

multiplex the analogic input or use a external a/d................

How can I multiplex the analogic input? I'm using an mbed starterkit by the way.

Here is a pic:

Maybe I can use the in/out puts on the second picture? But how?

Check out 8 Ch. DAC

from Sparkfun $10.

I am guessing that the 2 red pots are already connected to the MBED (with jumper's)

So no extera functionality :(

Cheers

Ceri

But what are the 2x 10 in/out puts (right pictre)?? What can I do with them? Can I use them for my needs? If yes, how to program it then?

socket for xbee module i suppose

-the only way to get more a/d is to use a external 8 channel a/d convertor preferred with i2c or serial output to the mosi/miso inputs

-to multiplex the input you use something like a HEF4051, control the selector of this chip by some pins of the mbed and then you got 8 channels to 1 a/d input

I dont get this. The analog output is always high?? Is it really an analog signal (0..3V3) or in fact just a digital signal. Seems you just need to know which of the 8 inputs is high. What are you trying to measure.

A multiplexer or external AD converter is a good solution when you really need the extra analog inputs.

Hi, it almost sounds like you are polling the inputs to read which one has the output voltage on it. A bit like reading a keypad or switch matrix. A basic circuit showing what you are intending to do would allow a much more focussed response.

JH

I indeed want to send out 1 output voltage (3.3 volt or so), and then check on each of the 8 inputs on which input pin the 3.3V returns...

OK, based on that all you need to use is any of the digital IO pins. You should not need to use those pins with ADC capability at all. Just read the state of each input pin to determine if it is high (3.3.V) or Low ( say 0 V). You need to read a bit about the Digital IO functionality and how to configure the pin as input or output, how to read the pin and maybe pull down resistors.

JH

Hello, can someone help me? I need a program that send the 20v voltage from mbed analog output pin 18 to a device. also, I can read that on a tear terminal program on the PC. Is that possible? thank you