Arduino UNO for controling?

Hello everyone, I'm new here. I am interested in building Prusa i3. As I looked around, I found everyone using Arduino MEGA with RAMPS shield for controling motors. Maybe anyone knows if RAMPS would fit Arduino UNO? Or are there any shields for UNO to control the motors?
Thanks in advice.

Uno won't work, not enough IO pins. The Uno has 14 digital pins which can't support 4 steppers (3 pins each) plus 3 end stops. This is before you add anything else you might want to use. The Mega has 56 digital pins in addition to many other additional capacities. There's a comparison chart of many of the most popular boards here.

edit: understood, thanks

Edited 1 time(s). Last edit at 03/14/2014 06:24AM by Capinho.

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cdru
Uno won't work, not enough IO pins.

Not necessarily true. My first printer ran off of a Duemilanove. You really only need two pins per stepper (STEP and DIR), enable is optional though nice to have. Can also use one pin to enable/disable all steppers at once. So that's 8 digital pins for stepper control (9 if you want to use enable/disable). Then 1 or 2 analog inputs for temperature readings (hot end and optional heated bed). Anywhere from 0 to 3 digital pins for endstops (endstops are really optional though nice to have, my first printer didn't have any). Then 1 or 2 digital pins for hot end and heated bed control.

So, that's anywhere from 9 digital pins and 1 analog pin for bare minimum control, and up to 14 digital pins and 2 analog pins for full control with end stops, heated bed, and stepper enable.

Of course this does leave a lot of features out that wouldn't be usable with the UNO due to lack of memory and pins, such as an LCD or SD card reader. Most modern firmwares are also too big to fit on it, though Teacup will fit.

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You could put a grbl shield on an Arduino UNO
and use grbl firmware to drive 3 motors
but you really need 4 --- X, Y , Z , Extruder
and some port to control hotend heater

Why UNO only?

Maybe dirve 3D printer from Smart watch?

I'm surprised that someone hasn't made a 3d printer controller from an Arduino UNO yet. To my knowledge, it should be possible to use some of the analog pins as digital pins. This would allow you to run four steppers (12 pins), three endstops (3 pins), two heaters (2 pins), a fan (1 pin), and two thermistors (2 pins). That would take a total of 20 pins, which the UNO has. Definitely not as powerful as RAMPS, but you could run a printer off it. I've actually thought about designing and making my own 3D printer controller shield for my UNO, but I've been too busy to do it.
As to plugging an UNO into the RAMPS board, I don't think that it would work because some of the stepper pins are too high on the MEGA for the UNO to attach to.

You can use only one endstop pin for all 3 of them, connected in series, if you set firmware to home one by one, and after homing one to move out of it so it is in continuity again.

Generation 2 Electronics was Duemilanove based and likely works with a Uno, too. Teacup is a firmware which fits into an ATmega328 easily and with some squeezing even into an ATmega168. With extruder and heated bed, of course.

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Generation 7 Electronics	Teacup Firmware	RepRap DIY

Hello,
I am new here and would like to know if I can use a UNO to control the extruder temp and bed temp only? I have a four axis controller with three additional relay outputs and am using Mach3 I also have a 16X2 LCD display I would like to incorporate.
Thanks

Quote
lanemfg
Hello,
I am new here and would like to know if I can use a UNO to control the extruder temp and bed temp only? I have a four axis controller with three additional relay outputs and am using Mach3 I also have a 16X2 LCD display I would like to incorporate.
Thanks

You're question should really be in it's own thread. Yes it could but it wouldn't be an elegent solution. It'd require a custom shield and extensive reconfiguring if you're using one of the common firmwares, but almost all of those firmwares would be overkill. A custom firmware could be written just to maintain the temp, perhaps signaled by one of the relay outputs from Mach3. You'd still have to figure out how to handle setting the temps unless you just went with a preset temp compiled into the firmware.

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lanemfg
I am new here and would like to know if I can use a UNO to control the extruder temp and bed temp only?

Yes and no. Yes, like you can use a standard firmware and just not send movement commands.

No, like an Uno has no means to read a thermistor or drive a heater. You need additional hardware.

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Generation 7 Electronics	Teacup Firmware	RepRap DIY

Quote
Traumflug
No, like an Uno has no means to read a thermistor or drive a heater. You need additional hardware.

Nitpick, but neither does a MEGA2560 or any other setup that uses a shield-like board plugged into an Arduino (or similar microcontroller). You're always going to need additional circuitry of some type, whether that's on a shield or built into a all-in-one board.

Thank all who replied,
After I posted my question I kind of thought that I had put it in the wrong place, live and learn. Anyway I got the information that I was seeking.