Reading multiple devices thru one ADC?

[Nforcer]

I've been playing on and off with PICs for about 6 months now. I want to start a new project that would help me learn more. I'm trying to read multiple remote Freescale pressure sensors that transmit a variable voltage up to 5V based on air pressure. The problem I have is I'm not really sure how to read more then one.
with my limited knowledge of electronics I think I can do it with transistors controlled with control pins on the PIC and they all connect to the single ADC on the PIC. Would this work and is there a better way that would allow me to have more channels. I also thought about seeing if I can use some of the 10F PIC I have laying around and making them be 1Wire devices. I've been playing around with these and like them. Any help would be appreciated

 

[karesz]

If you have only 1 channel for x inputs: you need e multiplexer , a switch for x lines to y or 1 output/or PIC I/O.
You can have such "8 to 1 Mux" and control the select inputs with you PICs digital outs_ if your sensor a digital signal is: is more simple to have some mux/selector...
K.

 

[Tahmid]

Hi Nforcer,
Which 10F do you plan on using? 'cos only the 10F220 and 10F222 have ADC. The rest, I don't think do.
You can use mux or you can use transistors as you stated.
Tahmid.

 

[ard]

Hi,

I've had excellent results using a CMOS switch 4066 for doing exactly this; 4 channels being read on just 1 pic pin.

Regards,

Anand

 

[wp100]

Hi,

Is there a reason why you cannot use Pics with more Analogue pins so you can connect each sensor direct to its own Pic pin ?

Many of the popular 16F and 18F chips have 12 or more Analogue channels, saves buying and fitting all those extra switching devices.