Arduino project? Suppliers?

[newshound]

I have a little project (logging temperature from a few thermistors) and it seems to me the Arduino might be the way to go.

Any recommendations for on-line suppliers for a Uno and a few shields? I already have breadboards, jumper wires, resistors and capacitors, power supplies etc.

TIA

[Another Dave]

Are you sure Arduino Uno is the way to go? Even chinese knock-offs seem to have got expensive; the cheapest I've found is a special offer (£7.38 down from £17) at Banggood:

Have you thought about the new Raspberry Pi Pico board. Well supported software and hardware and made in the UK.

Another Dave

[Bob Eager]

Cool Components. Nice guy, very fast service.

No connection, just a satisfied customer.

[The Natural Philosopher]

Pis have poor A to D supprt

[John Rumm]

A mate of mine had good results from this ebay trader for supply of nanos and other related stuff:

Might also be worth considering if you actually need a uno or whether a nano or other "smaller" version will do the trick?

[Chris Green]

Yes, I use Beaglebone Black for AtoD. It's like a Pi in that it boots into Linux.

[newshound]

Web guides seem to suggest Arduino matches my current project better than Pi. As an initial learning exercise I'm not particularly price-sensitive. Obviously, if I need to buy more I will look at the clones.

[newshound]

I'd seen them as one of the obvious options. Thanks for the advice, I will get an order in.

[newshound]

A nano might do, but I thought I'd start with an Uno as a first toy (that will do for the "trigger" project for my lad's business application). If I get on with it, I might try a Mega to monitor house room and heating temperatures.

[Another Dave]

I'm not talking about Pi computers but the Pico microcontroller.

Another Dave

[The Natural Philosopher]

Pis (including the PICO microcontroller) have poor A to D support

Better?

"A Raspberry Pi Pico has 12 Bits ADC with a quantization level of 4096. The ADC conversion process must be started by the user program and it may take several hundreds of microseconds for a conversion to complete"

Its slow and there is only one. You need something with a lot of ADC inputs for the OPS application

Arduino has 6 A to D inputs on a basic UNO.

QED

[John Rumm]

Not really.

The 12 bit pico ADC is clocked at 48MHz and takes 96 cycles per conversion, and so has a maximum effective sample rate of 500 kS/s The

10 bit ADC in the Arduino is a similar successive approximation device. However the default ADC clock is 125 kHz, and it take 13 clocks per conversion. So your maximum sample rate is a bit under 10 kS/s

So to be fair, for many control system applications, either are adequate, but you have significantly more bandwidth on the pico as well as more resolution, and it has *massively* more CPU grunt to process those samples should you need to.

Actually it has three channels. Like the Arduino it is one actual conversion device sat behind a multiplexer - so you are still limited to one conversion at a time.

So twice as many channels running significantly slower, and with less resolution.

I would not call that "better" in any general sense. As is always the case, much depends on what the application is.

or not as the case may be :-)

[RobH]

Pimoroni do a range of Arduino and Raspberry pi stuff, so maybe worh a look there.

[newshound]

Just as a follow-up, got my little temperature logger up and running with bits from Cool Components and ProtoPic. Quite enjoyed the challenge of learning an object orientated language, havn't done any proper coding for decades and that was in Pascal. Thanks again for the pointers.

[John Rumm]

Well done!

(might be a good project to add to the wiki?)

[leen...]

Probably a bit late but depending on your skill set etc. you could use an ESP32. You essentially code it in C++ (either using normal Arduino or the ESP libraries directly) or you can get images which allow you to integrate into home automation and get it to log the temperatures to HA and do things as a result. These are cheap, tiny and low powered but perfect for these types of activities. Couple of links if you are interested....

If you did want to go ahead with this I can help you get set up if needed.

[newshound]

My code is *very* dirty at the moment, I need to learn C++ classes / data structures. Lots of useful info out there, but it is quite disjointed. I've hacked two different examples that are saving stuff to card neatly enough, but in one of them the file datestamps are set to

1/1/2000, I'm probably using the wrong library. Sometimes the USB port locks up and I have to reboot the PC. Familiar minor irritations, but I'd like to get them trapped before offering as a working project!

[John Rumm]

I am happy to read through the code and comment on it (privately!) if you want.

[Andy Bennet]

Use a arduino nano instead. much smaller. used to get a pack of 3 for a fiver from amazon but i see they have noe gone up to £11.

[newshound]

Thanks, I have spotted that. The Uno is convenient for development, nano looks like the way to go once you are ready to hard-wire for an installation. Also the nano has a couple more analog inputs.