Low power PIC and make use of sleep cycles as much as possible.

regards Martin

The Arduino Boards might be a reasonable place to start. They have a few on-board power guzzlers that can be attacked with wire cutters. Removing LEDs, not using or minimising the linear regulator and maybe disabling USB all save power. Also, keeping the outputs low-current by design.

Depending on the application might be possible to use the Atmel chip's various power-saving sleep modes, ie hibernate the chip until an external event or a timer event wakes it up.

This website looks at power-saving on the Arduino Pro-mini board. Not played with a Pro-mini myself but recall our learned friend Mr Duncan Webster of this Parish does.

Lots of boards can be programmed with the Arduino IDE, maybe one of them is a low-power specialist. Just tried to find out how power a Nucleo-F446 uses with the programmer/debugger removed. Failed!

Dave

Not certain but I think these processors are designed to run on 3.3v because it is available from batteries without using a regulator.

Although not the same IDE, in fact does not need an IDE and is programmed in Basic, the Micromite is designed with low power features including sleep and clock slowing specifically for running off batteries.

Use the atmega 328 chip on its own ,you only need a crystal and 2 capacitors and it works the same as a Uno.

It will work on a supply between 1.7 and 5.5volt 

Edited By Maurice Taylor on 06/08/2020 16:19:54

+1 for using a 328 on its own; if you set it to 8 MHz it will be stable at 3.3V with a usefully reduced power consumption. They come in a variety of packages, both DIP (solderable with a standard iron) and SMD.

Depending on how you are using it, you may be able to let it sleep, to be woken up up when required by an interrupt from some other device. Since you mention using it for a clock, then a Real Time Clock chip, e.g. an MCP7940N, could provide the interrupt, as well as providing your clock functions.

Also, you don't actually need the crystal, the ATmega 328 has a built in crystal, which is adequate for timing its own cycle, though not for external tasks, like making a stopwatch.

I would thoroughly recommend this guy's website if you haven't dipped into stand-alone ATmegas:

http://www.gammon.com.au

John

There is a lot of useful information on using a bare atmega328 on the Arduino website.

**LINK**

Another alternative would be a PIC micro, but you would need a programmer and different programming software. I have used PICs in the past and there is a massive choice depending on what you want to do, but there is no doubt the Arduino is easier to programme.

Stuart

.

Given John’s parenthetic note in the opening post … That seems an excellent idea !!

MichaelG.

I'm a big fan of the ATTiny range from Atmel (well, Microchip owns them now). The ATtiny85 is extremely popular, and you can get ones that people have made into Arduinos if you really want. You could make one yourself and flash the arduino bootloader, or just say to heck with it and program it straight. If you're not going to be changing the program very often, there's no reason to waste the space with the bootloader.

Power wise they can be very efficient, though as was previously said using sleep states or low power states helps with that as well.

Here's a pic of an ATTiny based arduino. I bought a bunch of these ages ago so there may be better ones out there now. This one was called the digispark? The purple board next to it is one I made that uses smd components – this is a wireless temperature sensor, but for this one I'm pretty sure I used the Arduino IDE to write my program, then programmed the ATtiny(s) with a second arduino.

Low power ATtiny info is out there – here's at least one page that is a good place to start: ATtiny low power

I just spent near 2 hours digging into 'PlatformIO'…I think its a little presumptuous to just tell folk to 'ditch' the Arduino IDE…

Admittedly the Arduino IDE is not the greatest ( I don't use it – in fact I don't use any IDE – straight to the heart of the processor with embedded code and no OS..just a fast scheduler), but that IDE is very popular, commonplace, and although a little 'maker orientated', it is supported by a huge user base. That means a lot to someone just starting and finding the whole Arduinio, or any small micro based board, a little overwhelming. There are MANY forums where users assist and provide comments, many MANY library sources and many applications, easily adapted by new users, to blink that first LED or say 'Hello World'…

After the 2 hours on internet, reading all I could on PlatformIO, I found a lot of bling, heavy on the advertising selling its virtues , no useful comparison with other systems to assist a choice, how colourful it is, etc…User base is not easy to find. A SIMPLE intro to install, select your system, edit and compile 'hello world', etc was non-existant. All the splurb is very sell oriented and does not really do much to attract the new user, in fact the opposite! My comments are presented as though from a naive newcomer to the Arduino ( and workalikes) world – I am not a total newcomer myself – maybe 20 million lines of (disciplined military) code under the belt over the last 40 years…I guess I would get PlatformIO to work for me with little issue, but NOWHERE is it made easy to understand why I should , over say the Ard.IDE.. Nowhere do I find indications of ease of use, benefits, how or why it will make my life easier, etc, or at least, not without spending hours digging..

I don't say it is a poor system – I don't know anything about it, but as with so many open source softwares, the creators are Geeks, experts schooled in the art, and assume the rest of the world also are, and if not, 'get with the program'…

I don't know what John's level of expertise is in this field and maybe he would find it easy to convert/use, etc, although he did say he wishes to stick to what he knows and is comfortable with.

We all balk a little when faced with the learning curve presented by tackling a new CAD package, a new CAM package, etc, and many find it easier to stick with what you know, because it is much easier and quicker to get the job done, esp. if it is your hobby, and the objective is to make an Arduino based Clock, and not to spend half the project time fighting a new environment. With that as a perpetual given, why on earth do the vendors of such systems not present the system in a manner that does not chase one away with the first look!

I think that most members of this forum are 'mechanical' model hobbyists, as opposed to electronics or software hobbyists – that line is blurred hugely these days, with the easy access to modules that allow extensions to our hobby – but I would still suppose that the use of an Arduino module and some software is with the intent of making a 'model' better, or with more features, etc. In other words, the aim is not to spend the majority of the project's time on fighting a voluminous IDE and its surroundings,and writing software, but to make the model.

When I made my ELS for my lathes, the objective was twofold – to make threading on the lathe a pleasurable experience, and to learn about the mechanism of sychronised threading on a lathe. I used an Arduino type module to implement this, and although the software is what makes it work, writing the software was NOT the objective, and anything that makes the software creation more difficult is simply an annoying distraction.

Of course, it's not all the same strokes for all folks, and those who enjoy more the software and its environment are welcome to that world, but would it harm the Open Source Geeks ego that much if they stepped down a little into the real world and sold their stuff in a manner that was useful to most??

Not everyone is a software expert, doing software for a living, or merely interested in the latest bling_IDE for the sake of it..

In the two hours I could not fine what the minimum software overhead is when running this system on 'my' board – is there a bootloader? What size is it typically? How does it affect run-time measurements?..

John, I'd say stick with what you know and do the fun part – make the clock! If your interest in the IDE is as much fun, then maybe PlatformIO is for you…

My Rant for the day..

Joe

Edited By Joseph Noci 1 on 08/08/2020 08:22:40

As it is said, do what floats your boat! I must always be careful to not generalise to much…Individuals obtain project satisfaction in their own way, so prescribing alternative approaches is always fraught with with the subsequent need to duck…If at the end you enjoyed what you did, and maybe even learnt something along the way, then you won!

looking forward to seeing the clock – Obviously it's not just going to be a digital display of time…

Joe

Edited By Joseph Noci 1 on 08/08/2020 10:28:20

As a next step, I suggest tabulating the design requirement. (Andrew mentioned the importance of the overall design early on.) In particular inputs and outputs.

Before setting up a bare board or attacking a Nano with bolt cutters it's best to understanding what the circuit and external hardware must do, designing software & hardware together to minimise power consumption. Leaving out the power LED is obvious and safe, but other notions need a little thought. For example, bad ideas might include:

• Removing the USB chip when the design needs a USB interface
• Removing the USB chip on a Nano when the design depends on it as a 3V3 power source
• Disabling ADC when the design requires an analogue input
• Disabling SPI when the external hardware has an SPI module
• Disabling Timer1 when the software depends on millis()
• Using outputs to drive power hungry hardware, especially continuous loads.
• Ignoring PULL_UP & PULL_DOWN power implications when designing external hardware.
• Dropping clock speed when the software task is time critical.
• Stopping clocks to save power when fast reaction to interrupts or wake-ups is needed

I emphasise might because it all depends on the application. A simple switching application could be easy to power save; other code may be tricky! An Arduino advantage is it comes with all this stuff switched on and the processor is in a safe configuration. Beginner programmers don't need to worry about particulars, great except ease of use wastes power. Programmers who shave microamps become responsible for managing gory under-the-bonnet detail, which can be advanced stuff.

All do-able though, and interesting. Please keep us posted. I'm sure someone will help if you get bogged down in an unexpected complexity.

Dave

Edited By SillyOldDuffer on 08/08/2020 13:07:54

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Posted by Joseph Noci 1 on 08/08/2020 08:21:54:Posted by Andy Stopford on 07/08/2020 20:53:10:

Just a couple of points:

********************…..

Lastly, do yourself a favour and ditch the Arduino IDE – there are much better, easier to use alternatives, with full code completion, hints, colour coding, etc.

I use PlatformIO; it's available as a code editor plugin. I like the Atom editor, but you can use it with VSCode, and, possibly, others.

I just spent near 2 hours digging into 'PlatformIO'…I think its a little presumptuous to just tell folk to 'ditch' the Arduino IDE…

….

In the two hours I could not fine what the minimum software overhead is when running this system on 'my' board – is there a bootloader? What size is it typically? How does it affect run-time measurements?..

####################

Steady on Joe, I'm just venturing my own opinion; people are free to make of it what they want. You will find many complaints regarding the Arduino IDE in the Arduino forums. It does not make life easy for the beginner, which surely is the point (and was my own experience when I first got an Uno).

As it happens, I totally agree with you regarding the PlatformIO website. It's a model of corporate BS which seems designed show how much money they can afford to waste on some wacky web developer with a mission to put interested punters off.

However to make it clear – it is just an IDE, like the Arduino one, but with some bells and whistles to make it easier and more convenient to use. It doesn't run on your board, it doesn't have a bootloader, though it could be used to install one in conjunction with one of the Nick Gammon scripts I linked to.