The smallest Arduino?

Question

Arduino

Good afternoon!
There is such an abundance of information about Arduino on the Internet that everything is mixed up in my head and it turns out to be porridge. A question for connoisseurs, I need the smallest Arduino of all existing ones, or its analogue (I seem to have met something cheaper). I read it on Arduino.ru, it seems that the Pro Mini suits me, but it says that it is not suitable for prototyping and for permanent use, why? I don’t need soldered connectors, since they will only take up space (height), I need to solder two analog sensors and one power output, so I don’t see the point in such an abundant number of “pins”.
How is communication with the computer of such boards on which there is no USB output? I found that it is connected using the USB-Serial Light-version Adapter, but looking at the two photos they didn’t see anything in common, is it being soldered somewhere or what?
I have not yet found the question of energy consumption, is it really possible to power it from 3xAAA (or 4 pieces) and how long it will work (is there such information somewhere?)
Well, the last question, on some boards there is ATmega168 on some 328 and others, what is the fundamental difference besides the amount of memory and the frequency of work? I will have a simple program that, based on the operation of sensors, periodically provides power to the output. By the way, some versions are 3.3V for some reason, will the output also be 3.3 or 5V?
Thanks in advance for your replies.

Answer 1

Any Arduino is quite suitable for permanent use. Do not listen to anyone :)
Arduino Pro Mini is the smallest and cheapest option available, use it.
Offers to solder the strapping yourself - only if you have nothing to do in the evenings. It is better to leave it to the "fans of mass production", and in the free time to drink beer with friends.
The minimum consumption of version 3.3 v, it can also be bought on eBay in any quantity. But, unfortunately, there will be some level problems with it ...
A simple USB-UART is used to communicate with the computer, as you have already been suggested. Contacts are soldered into the scarf and such a device is simply connected (from the end).
If you need a power pack, then what's the point of low battery consumption? If you mean the relay, then it will consume more than the controller. If 220V is switched, then power the Arduino from there (for example, you can try a transformerless PSU).

Answer 2

Are you sure you don't just need an Atmel with harness? Flash the Arduino bootloader into it, and you will be happy:
microsin.net/programming/AVR/veroduino.html
habrahabr.ru/post/131589/

Answer 3

Perhaps this one .

Answer 4

Information on consumption can be found in the documentation for the controller used in the board with arduino, plus you need to take into account the consumption of the stabilizer. If, for example, you actively use the sleep mode of the controller (is it possible in an arduino?), then the consumption of the controller can be reduced to a few microamps, but the stabilizer used often does not give a chance - simple stabilizers that are put on arduins have too high their own consumption - 1-2mA easily as with bush. Even stabilizers themselves can drain the battery. You can, of course, refuse the stabilizer at your own peril and risk ...
Further consumption of the controller depends on the frequency at which it operates and its mode of operation. Adding here the uncertainty with the capacity of batteries from different manufacturers, we get too blurred ranges for estimating the working time from batteries.
Trying to increase the running time - yes, but calculating it is a very laborious and uncertain task.

Answer 5

And how do you like this thing? habrahabr.ru/post/177803/
Wind right to the bottom.
And this is not an arduino, but with a bootloader (no programmer needed).

Answer 6

The Arduino Pro Mini comes in two versions - 5 volt and 3 volt. For 5 volts, the maximum level is 5 V, for 3 volts 3.3 V.
You can put two (or three) 1.5 v batteries on the Arduino, and + one (or two) on the relay (through a transistor).
What device are you designing? Why batteries?