OK, I know it's been asked before and yes I have done A LOT of Googling but please read on...
I want to do some low power (long battery life) stuff so I need to have a minimal circuit (no LEDs, USB, etc) and I was looking for a board to build this on. I like the look of the one from Evil Mad Scientist but at $11.75 plus $6.55 shipping to the UK it seems quite a lot for a single board.
So I was just wondering what anyone else has done?
Does anyone have a PCB layout they are prepared to share?
Is there enough interest to pool together and get a batch made?
sirch:
I want to do some low power (long battery life) stuff so I need to have a minimal circuit (no LEDs, USB, etc) and I was looking for a board to build this on. I like the look of the one from Evil Mad Scientist but at $11.75 plus $6.55 shipping to the UK it seems quite a lot for a single board.
The Diavolino comes complete with chip, crystal, etc. And it's red.
Thanks for the replies, some interesting thoughts.
AlxDroidDev - I have a couple of modules on their own boards (real time clock and an SD Card breakout - TWI and SPI) plus I need to wire another couple of IO pins so I don't really need a custom PCB or headers as I am happy to solder wires to it. So I am realy looking for a board to mount the ATMega on, program it and connct up the periferals.
Given my level of incompetance, inexperience and inability to get anything right first time it would be good to have a board that is labelled up with pin designations, etc. so I have some chance of connecting the right wires.
sirch:
Given my level of incompetance, inexperience and inability to get anything right first time it would be good to have a board that is labelled up with pin designations, etc. so I have some chance of connecting the right wires.
In that case ... I think the Diavolino is actually a good choice.
A bit off-topic but I've been thinking about that board and can't see how it would be used? It looks like none of the pads are connected so when something is soldered in how do things get connected?
sirch:
A bit off-topic but I've been thinking about that board and can't see how it would be used? It looks like none of the pads are connected so when something is soldered in how do things get connected?
its weird isn't it? it seems to be all over ebay whereas good old veroboard (aka stripboard) is nowhere to be found. that stuff is actually called perfboard and is just individual holes with no power rails.
i guess it means no cutting of tracks is needed (handy for chips) but then getting power around the board must be a mess of jumper wires.
A bit off-topic but I've been thinking about that board and can't see how it would be used? It looks like none of the pads are connected so when something is soldered in how do things get connected?
When things are in adjacent holes it's easy to join them underneath with a blob of solder.
Or ... usually at least one of them has a long wire that needs to be snipped off after soldering (eg. resistors), in that case you bend the leg over to touch the adjacent component before soldering it.
sej7278:
its weird isn't it? it seems to be all over ebay whereas good old veroboard (aka stripboard) is nowhere to be found.
This works better IMHO.
sej7278:
that stuff is actually called perfboard and is just individual holes with no power rails.
i guess it means no cutting of tracks is needed (handy for chips) but then getting power around the board must be a mess of jumper wires.
It's not a real advantage in practice and you don't realize how much time you spend cutting tracks until you stop doing it. Cutting tracks also wastes a lot of holes when you're trying to do miniature stuff.
If you insist on doing "power rails" you can just put a bare wire across a row of holes underneath the board (solder the ends into place). Now you can poke wires through from above and solder them onto it. Voila! Power rail!
So how do you connect two components -e.g. connect a resistor to the pin of an IC? Big blob of solder? I am genuinely interested although I personally I don't find track cutting to be such a chore. For chips I often hacksaw across a number of tracks at once.
Back on topic I decided to go for an ATMega32 board (Arduino Leonardo), there are plenty on fleabay.
Bend resistor wire to touch IC pin (underneath board)
Apply solder to both
Snip off excess wire from resistor.
oh jees, that sounds awful! i think i'll stick to veroboard (if i can find any!) although i did see some breadboard-style perfboard which looks like a good compromise:
sirch:
I want to do some low power (long battery life) stuff so I need to have a minimal circuit (no LEDs, USB, etc) and I was looking for a board to build this on.
I have been using Sparkfun's Pro-Mini for exactly this purpose. They're easy to get hold of, and quite cheap at $10. To get below ~1mA you just need to cut one trace to disconnect the regulator and power LED. With this small modification (and appropriate programming) you can get the current consumption below 3uA. The modification can be undone be connecting the two VCC contacts together.
Sparkfun have revised the PCB layout since I made this picture, but the cut is still in approximately the same spot. The Pro Micro can also be modified, although it's slightly harder to do.
Look at all the little extra jumper wires he had to put in, eg. The two little black ones below the caps on the crystal. I would have just bent the legs of the caps across underneath the board.
Also the blue power wire that goes around at bottom left, then has another jumper to get to the chip. Two whole wires where a blob of solder underneath the board would have done the job.
