Fzyrrx
Posts: 1
Joined: Tue Oct 10, 2017 10:44 pm

Arduino or raspberry

Tue Oct 10, 2017 10:54 pm

I am building a small engine water brake dynamometer. I have an analog signal Wheatstone bridge s beam load cell for load on the water brake and a digital Hall effect swirly for rpm.

My question is what board will best suit my needs to collect rpm and load voltage inputs simultaneously and export to a spreadsheet using a USB connection.

How much programming is involved for either solution?

Thanks

Empyreal
Posts: 10
Joined: Tue Jul 05, 2016 1:41 pm

Re: Arduino or raspberry

Wed Oct 11, 2017 4:26 am

For analog, I'm guessing maybe a combination. For higher level UI / Presentation, an RPI is going to be much better, richer, easier, etc.. For lower-level data collection, especially analog, the Arduino is going to be easier and cheaper, fwiw.

I'd suggest using both. There's a tiny learning curve going from the Raspberry Pi to the Arduino, but if you get a Node MCU (ESP8266) around around $7 or so from Amazon, and flash MicroPython on it, it's a straightforward process.

Heater
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Joined: Tue Jul 17, 2012 3:02 pm

Re: Arduino or raspberry

Wed Oct 11, 2017 8:35 am

Empyreal,
There's a tiny learning curve going from the Raspberry Pi to the Arduino, but if you get a Node MCU (ESP8266) around around $7 or so from Amazon, and flash MicroPython on it, it's a straightforward process.
Are you suggesting using three processors in this solution. Raspi, Arduino and ESP8266 ?

That sounds anything but straightforward. And huge overkill for a simple measurement and display task.
Memory in C++ is a leaky abstraction .

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Ronaldlees
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Re: Arduino or raspberry

Wed Oct 11, 2017 12:16 pm

I'm sure he's saying to just use the Node MCU (ESP8266) in combination with the Raspberry Pi. The ESP8266 is much closer to the Arduino world than the Pi world. Relative to the Arduino, it's a hopped up, faster, MCU board with more memory and built-in WiFi. I like the Particle Photon which is a slightly richer board (IMO) in the same category. It would make interfacing tasks easier as it's more versatile.
I am the Umbrella man

Heater
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Joined: Tue Jul 17, 2012 3:02 pm

Re: Arduino or raspberry

Wed Oct 11, 2017 1:23 pm

Ronaldlees,
The ESP8266 is much closer to the Arduino world than the Pi world.
Certainly the Arduino and the Pi are like chalk and cheese.

It's just that in my mind the Arduino and the ESP8266 aren't very close either.

The Arduino is a dinky little 8 bit MCU. The ESP8266 is a 32 bit processor running at up to 160MHz. The ESP has 96K of RAM. That's difference enough before we get to the inbuilt WIFI.

If the suggestion is to use the ESP8266 and MicroPython why even mention the Arduino?

I'm missing a point here.

Anyway. We now have the ESP32 which sounds like a much nicer proposition.

The particle modules look interesting. Especially if you want 3G connectivity.
Memory in C++ is a leaky abstraction .

MarkTF
Posts: 318
Joined: Tue Mar 03, 2015 4:59 pm

Re: Arduino or raspberry

Wed Oct 11, 2017 2:05 pm

A simple Arduino (Uno) is likely the better choice for collecting data from the sensors since it has an integral analog to digital converter which you'll need and getting deterministic timing for the RPM measurement is more straightforward. A strain gauge will probably also need a suitable amplifier if it is not part of the sensor. Sensor interfaces are well documented in any number of places (e.g. https://learn.sparkfun.com/tutorials/ge ... load-cells). With a fairly minimal amount of effort the Arduino can be configured to stream ASCII measurements to the USB/serial port, maybe 50 lines of code and something that could be prototyped by someone familiar with Arduino in a few hours.

There will be coding effort on the USB host side (presumably a PC of some sort, but of course a RPi would do here) to take the serial measurement stream and write it to a spreadsheet compatible file format. This is pretty straightforward in Python for instance. With a bit more effort the host side application could log and log/graph the data directly without going to the spreadsheet.

I can't think of a reason one would prefer an ESP8266 for this application as there is no WiFi requirement and micro Python for a system with real time requirements (measuring RPM) probably isn't the best option. Frankly I'm baffled by this tangent in the thread.

mlepage
Posts: 95
Joined: Tue Jun 12, 2012 1:58 am

Re: Arduino or raspberry

Sat Oct 14, 2017 11:38 pm

You just want to collect data and feed it out through USB?

I'd suggest Arduino, output as CSV text over the USB serial connection.

On the host side (whatever PC you're using), read the CSV over the USB serial connection and do with it what you wish.

You can also get fancier and send simple commands as text over the serial (e.g. START, STOP).

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