Driller Pi
Posts: 4
Joined: Tue Nov 22, 2016 4:01 pm

Data acquisition system project

Tue Nov 22, 2016 4:44 pm

Hi guys! Need a piece of advice.

I have to design a data acquisition (DAQ) system as a project at school.
Initially I was going to use Arduino microcontroller and Adafruit boards for it, but one of my friends suggested that Raspberry Pi may be more suitable for this purpose.

So briefly what my DAQ system has to be able to do:

1. Acquire and record signals from 6 ANALOG sensors.
2. Operator should be able to create, name a recording file. Also he should be able to control a START/STOP moment of recording. It is important that program interface won't be to complicated, because it will be used by "oldschool" drill operator who is not very familiar with modern technology :D .

It seems pretty easy, but I'm not sure if it's possible to do with Raspberry as I know close to nothing about it.
Please advise


User avatar
mikronauts
Posts: 2708
Joined: Sat Jan 05, 2013 7:28 pm
Contact: Website

Re: Data acquisition system project

Fri Nov 25, 2016 12:53 am

The question is meaningless without knowing:

- what kind of analog signals we are talking about (voltage/current/resistance)
- the range of the analog singals
- desired number of bits of resolution
- desired sample rate
Driller Pi wrote:Hi guys! Need a piece of advice.

I have to design a data acquisition (DAQ) system as a project at school.
Initially I was going to use Arduino microcontroller and Adafruit boards for it, but one of my friends suggested that Raspberry Pi may be more suitable for this purpose.

So briefly what my DAQ system has to be able to do:

1. Acquire and record signals from 6 ANALOG sensors.
2. Operator should be able to create, name a recording file. Also he should be able to control a START/STOP moment of recording. It is important that program interface won't be to complicated, because it will be used by "oldschool" drill operator who is not very familiar with modern technology :D .

It seems pretty easy, but I'm not sure if it's possible to do with Raspberry as I know close to nothing about it.
Please advise
http://Mikronauts.com - home of EZasPi, RoboPi, Pi Rtc Dio and Pi Jumper @Mikronauts on Twitter
Advanced Robotics, I/O expansion and prototyping boards for the Raspberry Pi

User avatar
bensimmo
Posts: 4123
Joined: Sun Dec 28, 2014 3:02 pm
Location: East Yorkshire

Re: Data acquisition system project

Fri Nov 25, 2016 7:11 am

Yes the Pi can do what you need and give you the computer to do it on all in one.

For school projects I like to think of them as 'stuff teachers can use' which means simple and does what they need with no setup and few options.

Look at gpiozero and python.
gpiozero will.make the python coding easier (it a module for it for easy interfacing provided by the RasperryPi people)
Check the Make and Learn section of this website for ideas and getting into it.

You can practice datalogging ideas using the sense hat emulator (the website provides details) then expand from there for specific devices using gpiozero in python.

That should give you some starters, but don't just copy&paste, read through and learn it :-)

Driller Pi
Posts: 4
Joined: Tue Nov 22, 2016 4:01 pm

Re: Data acquisition system project

Fri Nov 25, 2016 4:30 pm

mikronauts wrote:The question is meaningless without knowing:

- what kind of analog signals we are talking about (voltage/current/resistance)
- the range of the analog singals
- desired number of bits of resolution
- desired sample rate
- sensors output is 0...+5V
- 10 bits would be sufficient
- sample rate will be pretty low...from 10 to 100 readings per second

User avatar
B.Goode
Posts: 8024
Joined: Mon Sep 01, 2014 4:03 pm
Location: UK

Re: Data acquisition system project

Fri Nov 25, 2016 4:41 pm

One critical difference between the two types of board that does not seem to have been highlighted:

An Arduino can read/report analogue signals. (ie. varying over some range such as 0-5v)

An RPi as shipped only has the ability to read/report digital signals: Hi/Lo, On/Off.

So to be able to handle analogue sensors you will need to add some form of external Analogue to Digital conversion. Not a showstopper, but something to be aware of.

Driller Pi
Posts: 4
Joined: Tue Nov 22, 2016 4:01 pm

Re: Data acquisition system project

Fri Nov 25, 2016 4:55 pm

Thank you guys for your comments. At least now I know where to start.

I thinks the "hardware" part won't be too complicated for me. Coding is the tricky part as I have almost no experience in it.
DAQ system is just the first part of my project and I'm actually more interested in the data itself and its processing.

Driller Pi
Posts: 4
Joined: Tue Nov 22, 2016 4:01 pm

Re: Data acquisition system project

Fri Nov 25, 2016 5:00 pm

B.Goode wrote:One critical difference between the two types of board that does not seem to have been highlighted:

An Arduino can read/report analogue signals. (ie. varying over some range such as 0-5v)

An RPi as shipped only has the ability to read/report digital signals: Hi/Lo, On/Off.

So to be able to handle analogue sensors you will need to add some form of external Analogue to Digital conversion. Not a showstopper, but something to be aware of.
Thanks. richrarobi already posted some links regarding this.

User avatar
mikronauts
Posts: 2708
Joined: Sat Jan 05, 2013 7:28 pm
Contact: Website

Re: Data acquisition system project

Fri Nov 25, 2016 7:12 pm

An MCP3008 will give you eight channels 0-5V if powered from 5V

See http://www.mikronauts.com/raspberry-pi/ ... and-howto/

Ignore the SPI de-multiplexer, but pay careful attention to the voltage divider for MISO
Driller Pi wrote:
mikronauts wrote:The question is meaningless without knowing:

- what kind of analog signals we are talking about (voltage/current/resistance)
- the range of the analog singals
- desired number of bits of resolution
- desired sample rate
- sensors output is 0...+5V
- 10 bits would be sufficient
- sample rate will be pretty low...from 10 to 100 readings per second
http://Mikronauts.com - home of EZasPi, RoboPi, Pi Rtc Dio and Pi Jumper @Mikronauts on Twitter
Advanced Robotics, I/O expansion and prototyping boards for the Raspberry Pi

Return to “Automation, sensing and robotics”