Hi, i want to make a miniCNC milling machine, with DVD/CD drivers motors. I see many tutorials but i really need buy nothing. I have many attiny85 and attiny84 from samples, Will be possible to use an attiny as a stepper controller and control all them (3) from an arduino? And, of course, use an open software to control all the system?
I'm sure is possible, but i have doubts about the software ...
Not unless you can figure out how to synchronize two ATtiny85s (each only has 2 PWM output ; 0 & 1) . I have never tried that. I use ATtiny85s driving leds and generating 50% duty cycle waveforms but never used it for steppers. Maybe it's simple to synchronize them but I'm not going to speculate.
raschemmel:
Not unless you can figure out how to synchronize two ATtiny85s (each only has 2 PWM output ; 0 & 1)
Three. An ATtiny85 processor has THREE Arduino compatible PWM outputs.
I stand corrected. That's still not enough for a stepper motor though.
Stepper motors don't need PWM outputs.
But CNC code will need lots of memory.
You will waste so much of your own time trying to work with Attinys that you will wish you just got an Atmega328 at the start.
...R
You will waste so much of your own time trying to work with Attinys that you will wish you just got an Atmega328 at the start.
I second that!
The tiny85 is perfect for a few small projects, but in cost-performance, the Atmega328 wins. The cost penalty is 2.45x and the SRAM boost is 4x... Ex: Newark in 25 qty:
Tiny85 ... $0.85
Mega328 ... $2.08
208 / 85 = 2.44
It gets even better for the mega1284-PU. But @40 pins, size is a but if an issue, perhaps.
Ray
If you had breadboarded a 328 at the start you would have been finished by now.
Take a look at this - http://forum.arduino.cc/index.php/topic,84809.0.html
I used an ATtiny2212. has a few more pins than needed but that is generally easy to deal with...
Started out in Arduino but went to Assembly for the final.
Easy to do regular stepping, wave stepping or half stepping. Could use some of the unused pins to select.
Started out in Arduino but went to Assembly for the final.
How do you do this ? I used to program in ASM back in the day but I don't know how to do it for my many arduinos (at least 6).
mrburnette:
You will waste so much of your own time trying to work with Attinys that you will wish you just got an Atmega328 at the start.
I second that!
I third it.
I used to use ATtinys a lot but since the $3 Pro Minis appeared on eBay it's simply not worth it any more. I still use ATtimy85s for things which have to be really really small but for everything else it's Pro Minis all the way.
but since the $3 Pro Minis appeared on eBay it's simply not worth it any more. I still use ATtimy85s for things which have to be really really small but for everything else it's Pro Minis all the way.
This definitely changes the cost-performance equation in favor of the 328. The convenient form factor for the ProMinis make it very usable and at $3 they simply become a permanent part of a project. For the last 9 months or so, I have been affixing them to the back of the LCD using industrial velcro and soldering the entire thing into place. The Velcro will allow you to remove the Pro Mini if you absolutely must, but otherwise keeps the board firmly affixed. This has the added benefit of making the G/LCD layout very clean and soldering the wiring and keeping the wiring short makes the packaging neat.
Side note: The Industrial Velcro has a wide-use temperature range and the adhesive will not turn loose easily. Those little GPS units for $16 from China that have the integrated antenna are easily mounted to the inside of the project enclosure with Velcro.
Ray
raschemmel:
Started out in Arduino but went to Assembly for the final.
How do you do this ? I used to program in ASM back in the day but I don't know how to do it for my many arduinos (at least 6).
The Arduino IDE lets you use assembly language (".S") files in libraries.
Here's an example I wrote, install in your libraries folder...
asm_test.zip (126 KB)
Awesome ! Thanks !
but since the $3 Pro Minis appeared on eBay it's simply not worth it any more. I still use ATtimy85s for things which have to be really really small but for everything else it's Pro Minis all the way.
DITTO ! I got mine in 7 days. Great idea with the velcro. I have about 1 square foot of velcro on my bench if you add up all the little pieces for the 10 or 15 breadboards and UNOs and Pro-Minis, etc... I bought a dozen small breadboards at Fry's and by the end of 2 weeks they all had circuits on them. The circuits change almost weekly but they are great for little circuits like the RF24 LedRemote library example where you control 6 leds with 6 push buttons and toggle them via radio.