Sorry for the dumb question but I am new to this. I tried to look at projects (and maybe someone can just point out one with lots of step motors .... I just see projects with two or three ... and that will answer all my questions) but am still confused.
I have been looking at the different boards and see the UNO has 14 i/o ... the MEGA 54 I/O
Lets say I wanted to control 12 step motors. Each controller had 4 wires ... that is already 48 outputs I would need.
Then if you add some switches and such I will go over 54
What do you guys do?
Is there an expansion board for I/O or ?
Can you get 48 outputs for motor controllers or is there a limit of the number of step motors (assuming 4 wires each) you can run off an ARDUINO?
Plenty of expansion boards, you can get thousand of outputs from a single Uno. It's just going to be hard to code, and you're bound to run into various scaling problems if you go that crazy.
Anyway for your application (connect even more steppers) it seems you have to look at general purpose port expanders such as the MCP23017 - you can connect 8 of those, 16 ports each, total 128 extra pins, at a cost of just two (the I2C ones). Powering all those steppers may become a serious challenge!
I had not looked at 3 wire motors since the more common ones I see 4 wires going into a driver.
Long story short ... I was looking at some old fashion synchronized clocks (like in a school). Say one in every room of a house (or in my case workshop since I have 5 separate areas that I would like clocks in plus maybe one outside).
Each would have 3 motors.
Each motor would also have a "zero" switch to bring them back to sync once a day.
That is a lot of motors .... but much simpler then one motor and a bunch of gearing (at least for me).
Again .... a lot of I/O.
Not much of a load ... only the hands on the clock.
I wanted to do a simple clock first with three motors just to try it but didn't want to go too far if the idea would not work for multiple clocks.
I am guessing I would use a GPS to get the time signal to correct them once a day (found a GPS shield).
There are very few clocks on this planet that use more than 1 motor. You would be wise to check out how clocks actually work. You will also be shocked how cheap clock mechanisms are and how easy it is to open them up and modify them.
The clocks will be a long way apart. I suggest an Arduino located at each one will be cheaper than the length of wire. (I'm thinking school classroom size rooms. Your workshop may be smaller.)
For most of the day, all the clocks will step at exactly the same time, in the same direction. So you only need one 'step' line and some way to individually control each clock's direction.
Do you live in a cold climate? Having all those steppers powered up 24 hours per day will give you a significant amount of heating for your workshop. Once again, regular clock mechanisms run on a single battery for years, so they are millions of times more efficient than a stepper. (Even though they are a type of stepper.)
Wow, I am that memorable ... hmmmm maybe not a good thing.
Things got busy but I just keep this idea kicking around thinking one day I am going to just start ordering parts so I can try it.
I actually got the idea for the indoor synchronized clocks last week after a power failure.
Three of the clocks had batter back up but non came back up at exactly the same time.
I know it is dumb but I am a machinist and love detail. Things like this drive me nuts. Plus I hate changing out batteries (though I faithfully do each year in the smoke alarms).
I think the idea of a few clocks in the shop are much more realistic for a first project then a clock tower.
As I said, I actually found a number of clock projects ... looked interesting.
The one thing I didn't see was multiple clocks.
I do love listening to every ones input. I didn't think about just making multiple individual clocks that all sync to gps or wifi ... might be cheaper and easier in the long run then a bunch off one Arduino.
I really love looking in on this forum .... always interesting ideas and thoughts.
As far as I can see you got a lot of useful advice in your other Thread so I have no intention of reading the two of them just to make sure I don't repeat anything that has already been said. I mentioned in the other Thread that you should not split up your questions.
You can click Report to Moderator and ask for the Threads to be merged if you wish.
Sorry, started as a different problem asking about I/O
I was all set with going with the gearing suggested but then after doing more reading found out about 1/3 step controller (mentioned in an article but I have not found one yet).
I will go back to the other post and put up the questions since is it more relevant to that discussion.
there are micro-stepper drivers that use 2 pins for the signal, then control a 4 wire motor.
consider that you will NEVER turn back time, so you can tie the DIR pin high or low and only need one output [ for each motor] from your Arduino to run a dozen motors.
since your load is so small, the small drivers will be able to power a motor that can turn the hands of time.
I recall clocks in my 1950's highschool classrooms were ALL synchronized to a master clock in the school office. I wondered if they were still around. They are, and would be a WHOLE LOT EASIER than what you are designing.
Look at commercial systems controlled by 2.4 GHz control clock. Think digital clocks in each room, all synced to one control clock. There are even systems tied to the WWVB atomic clock.