Hope this is the right forum to post my question. I have completed my 1st project with Arduino, using the "development" board that came with the kit. For the reference it involves 3 sets of scales/load cells and the display. The wiring and the code is working as expected. The issue is I started this project because I need to use that set up in "production", e.g. the purpose was not pure learning, that is something I intend to use. I will 3d print the case for the board and batteries, solder the wire harness, etc.
My question is - what is the "right" board to purchase to be used daily? I want to keep the Uno for futore developments, plus I guess I need a board where I can solder the wiring to (and not use these patch cable connectors). I'd also need external power (batteries?) and - ideally - have more inputs and the TFT plus 3xload cells used pretty much all that Uno has. If I want in the next version to use Bluetooth, I'm out of pins.
The Nano is the "working" version of the UNO, you can get clones with the headers not fitted. It has two more Analog-only inputs - A6 and A7. But if you do not need to connect it to a computer with USB, then a Pro Mini.
I'd second Pauls recommendation of the Nano and Micro, both are great boards for little money.
However noting that you want bluetooth - well you can add a bluetooth module, but it will add to your connections; and connections on the nano and micro are limited.
As you're a newbie I'd recommend you get a MEGA; The Arduino Mega has 16 analog inputs, 15 PWM channels, and is hardware compatible with Arduino shields. Plenty connectivity for most applications.
You can develop your hardware using the MEGA, then move your design to a micro or nano when it is working.
Another option is the ESP-WROOM-32 Devkit - which has wifi and bluetooth built in; but its not really a board for beginners.
Also, you've talked about batteries. For longest battery life (a) at the hardware level you want to get as close to the barebones ATMEGA328P (MCU chip) as you can and (b) at the software level, using sleep mode if appropriate.
Paul__B recommended Mini, not Micro. These are different. But Micro is another option. Quite a good one, in fact, as Micro has an available hardware serial port that is not used to communicate with the PC and so could be used for connecting a Bluetooth module.
I'd recommend you get a MEGA
But the OP said
a board where I can solder the wiring to (and not use these patch cable connectors).
You can develop your hardware using the MEGA, then move your design to a micro or nano when it is working.
If you have used more pins than micro or nano have, which is the reason for getting mega, then you won't be able to do that without redesigning your circuit and changing your code.
I think with its greater connectivity the Mega is a useful board for prototyping. Also it accepts a wide range of shields that plug in avoiding the use of patch cable connectors.
You can even make your own shields of vero board as I did in THIS PROJECT
If you have used more pins than micro or nano have, which is the reason for getting mega
then you can re-examine your project criteria - or just use a mega.
Oh, I was told you could not use veroboard for making shields because of the strangely not-quite-aligned pins on Uno/Mega. But yours looks neat enough.
have more inputs and the TFT plus 3xload cells used pretty much all that Uno has. If I want in the next version to use Bluetooth, I'm out of pins.
That doesn't sound like it should use all Uno/Nano's pins. I know most load cell modules/chips use a non-standard interface, but I suspect some pins can be shared between them and with other devices. Most TFT use SPI interface and most of the pins for that can be shared with other SPI devices. For example you could add more pins using an SPI I/O expander chip. So there are alternatives to using a Mega when more pins are needed.
You may also want to consider one of the "rugged" clones from rugged circuits. They are made a little more durable along with screw terminal connections. You can get a rugged mega or uno clone. none of these boards should be used in a life-critical application.
I've done some reading based on the info provided. Looks like Nano is the best way for me to go forward with the current version of the solution. For V2 (with BT and touchscreen) I'll use one of the other suggestions provided (with optimization of pin usage as suggested) plus SPI I/O expander chip could be a good idea as well.