Hello everyone

We can connect eight temperature sensor's with one MCP3008. if I have 12 devices and I want to measure their temperature so I need 12 temperature sensor's to measure temperature of each device. I don't know How many MCP3008 need be interface with Pi to measure temperature of 12 devices

I found it on the internet, that it depends on the address of ADC MCP3008 But I do not understand how many MCP3008 need to measure temperature of 12 devices ?

 

Each device has one ADC but 8 eight selectable channels so the answer is two MCP3008's... You would need one CS per unit.

 

Hello,

When you use single ended inputs, you will need two MCP3008's.
When you use differential inputs, you will need three MCP3008's.
You can select the MCP3008's using the CS input.

Bertus

 

so selection of adc depends on the CS input

Raspberry pi3 have 26 GPIO pins available

How many MCP3008 can be interface with raspberry PI 3 ?

 

so selection of adc depends on the CS input

Raspberry pi3 have 26 GPIO pins available

How many MCP3008 can be interface with raspberry PI 3 ?

It can be a really large number in theory with line decoders. http://www.ti.com/lit/ds/symlink/sn74hc138.pdf
By decoding just gpio 8 pins to individual selection lines we can have 256 CS pins.

 

So selection of adc depends on the CS input

Not entirely.... The ADC module channels are selected by software you would select the first ADC module and traverse the channels reading each in turn ( or which ever order you want ) then select the second...

When you use differential inputs, you will need three MCP3008's.

Unfortunately, this is a single ended ADC only! so all eight are available on each chip..

How many MCP3008 can be interface with raspberry PI 3 ?

After the clock, SDO and SDI you need a CS pin for each ADC IC so...… Loads...


**** Whoops Apologies Bertus…. This device does support differential sampling!!!

 

Hello,

Unfortunately, this is a single ended ADC only! so all eight are available on each chip..

How about this table in the datasheet?



Bertus

 

How about this table in the datasheet?

I have already apologised for my error... I use these from time to time, but I missed that part of the datasheet I don't use differential!

 

With 24 bits you can select one of 16,777,216.
How many do you need?

 

Let's take one example There is a company that has 220 devices and I have to know the temperature of each device. I have make a system that can measure the temperature of each device.

I need to purchased raspberry pi, temperature sensor and MCP3008 to make whole system.

I think I have to purchased 220 temperature sensors. I don't have any idea for raspberry pi and ADC

How many raspberry pi and MCP3008 need to make whole system ?