Which board and controller to buy ?

[roborg]

Hi,

I am looking to purchase a board and a stepper motor controller for my project. I need to be able to control two stepper motors (mostly one after another, but may be simultaneously in future) and need support for long running timers (interval between timer events can be of the order of days or weeks). It looks like Axon is very expensive for this, so I started looking at Arduino and like it for following reasons:

1) USB port can be used as power source
2) Arduino IDE works on Windows/Linux/Mac (I mostly use Linux and Mac)
3) Program can be uploaded directly using USB port (no serial ports or other cables needed) - this is big plus for me as I am not comfortable dealing with serial/parallel ports).
4) No need of hardware programmer
5) C like programming language
6) Lot of example source code
7) No need to purchase any other software (compiler or IDE etc.)
Arduino Mini (or Nano) seems attractive w.r.t size

Not that Axon doesn't have all or some these, but I think it is expensive for the needs I mentioned above (i.e., driving two stepper motors every now and then). Now, the question is are there cheaper/better choices than Arduino Mini/Nano ? I looked at other boards but some need hardware programmer, some require special development environments etc. and cumulative cost comes close to Arduino. Can you please share your experiences ?

Also, can you please suggest a good stepper motor controller that I can use with Arduino ? Are there controllers that can control both uni-polar and bi-polar motors ? or different controllers are needed for both ? I looked at the following links, but still not clear what to buy exactly.

http://www.societyofrobots.com/member_tutorials/node/169
http://www.societyofrobots.com/member_tutorials/node/173

Specifically for Arduino, I saw

http://lusorobotica.com/index.php/topic,106.0.html

but not sure if it can drive multiple stepper motors.

Any help is greatly appreciated.

Thanks,
RO.

[cyberfish]

Arduino at $30 is about as cheap as it gets.

I have built my own, and it comes to about $15 + hours and without the nice USB port. Probably not worth it.

The microcontroller chip itself costs almost $10 (for higher end ones), and the board costs a few $s, so you probably won't get much cheaper than $30. They really aren't making much .

[waltr]

USB port can be used as power source

Will this also power the Stepper motors? USB port power is limited.

[Soeren]

Hi,

The microcontroller chip itself costs almost $10 (for higher end ones), and the board costs a few $s, so you probably won't get much cheaper than $30. They really aren't making much .

Gee, is AVRs really that expensive??

This is just one out of a vast range of PIC processors which would be much more than it takes to control two steppers and it's $1.56 in PDIP in one off. Much less could do it (like the trusty 12F675 at $1.10), but this was just a random pick.

Here is one that kicks a bit more butt, 100 pins and 80MHz clock
A bit more of the features:
 USB 2.0 On-The-Go Peripheral
 Dedicated DMA Channel for USB OTG
 512K Flash (plus 12K boot Flash)
 32K RAM (can execute from RAM)
 4 Channel Hardware DMA Controller
 Flash prefetch module with 256 Byte cache
 Lock instructions or data in cache for fast access
 Programmable vector interrupt controller
 Fast and Accurate 16 channel 10-bit ADC,
 Max 1 Mega sample per second at +/- 1LSB, conversion available during SLEEP & IDLE
 2 wire programming and debugging interface
 JTAG interface supporting Programming, Debugging and Boundary scan
 Fail-Safe Clock Monitor – allows safe shutdown if clock fails
 2 Internal oscillators (8MHz & 31KHz)
 Hardware RTCC (Real-Time Clock and Calendar with Alarms)
 2 x SPI, 2 x IIC
And loads more.

One off price $7.59

Damn it must sucks to be married to Atmel   

[Soeren]

Hi,

USB port can be used as power source

Will this also power the Stepper motors? USB port power is limited.

If you've got some really tiny ones perhaps, but in general no.

What exactly are you making, with what model motors and what is it intended for?
Controlling two steppers is not a big job, but I assume it should be controlled in response to some outer activity or conditions.
You get better advice when you give us all the gory details.

[cyberfish]

The one arduino uses (ATmega328P) is $5. ATmega8's are about $3.

I use AVR because I have an arduino, and I can use it as an ISP to make as many "arduino clones" as I want without a real hardware programmer.

The arduino library is really nice, too. Includes just about everything.

[Admin]

Here is one that kicks a bit more butt, 100 pins and 80MHz clock
A bit more of the features:
 USB 2.0 On-The-Go Peripheral
 Dedicated DMA Channel for USB OTG
 512K Flash (plus 12K boot Flash)
 32K RAM (can execute from RAM)
 4 Channel Hardware DMA Controller
 Flash prefetch module with 256 Byte cache
 Lock instructions or data in cache for fast access
 Programmable vector interrupt controller
 Fast and Accurate 16 channel 10-bit ADC,
 Max 1 Mega sample per second at +/- 1LSB, conversion available during SLEEP & IDLE
 2 wire programming and debugging interface
 JTAG interface supporting Programming, Debugging and Boundary scan
 Fail-Safe Clock Monitor – allows safe shutdown if clock fails
 2 Internal oscillators (8MHz & 31KHz)
 Hardware RTCC (Real-Time Clock and Calendar with Alarms)
 2 x SPI, 2 x IIC
And loads more.

One off price $7.59

Damn it must sucks to be married to Atmel   

The 32-bit AVRs have similar features at a similar price.
(but yea, I'm married to Atmel definitely)


roborg, keep in mind that you'll probably reuse your microcontroller for other projects in the future that might require different features. You may find the single hardware UART on the Arduino a bit limiting, for example.

[chelmi]

Hi,

The microcontroller chip itself costs almost $10 (for higher end ones), and the board costs a few $s, so you probably won't get much cheaper than $30. They really aren't making much .

Gee, is AVRs really that expensive??

This is just one out of a vast range of PIC processors which would be much more than it takes to control two steppers and it's $1.56 in PDIP in one off. Much less could do it (like the trusty 12F675 at $1.10), but this was just a random pick.

Here is one that kicks a bit more butt, 100 pins and 80MHz clock
A bit more of the features:
 USB 2.0 On-The-Go Peripheral
 Dedicated DMA Channel for USB OTG
 512K Flash (plus 12K boot Flash)
 32K RAM (can execute from RAM)
 4 Channel Hardware DMA Controller
 Flash prefetch module with 256 Byte cache
 Lock instructions or data in cache for fast access
 Programmable vector interrupt controller
 Fast and Accurate 16 channel 10-bit ADC,
 Max 1 Mega sample per second at +/- 1LSB, conversion available during SLEEP & IDLE
 2 wire programming and debugging interface
 JTAG interface supporting Programming, Debugging and Boundary scan
 Fail-Safe Clock Monitor – allows safe shutdown if clock fails
 2 Internal oscillators (8MHz & 31KHz)
 Hardware RTCC (Real-Time Clock and Calendar with Alarms)
 2 x SPI, 2 x IIC
And loads more.

One off price $7.59

Damn it must sucks to be married to Atmel   

Do they have a good, open source C compiler now? :p

[Cristi_Neagu]

The 32-bit AVRs have similar features at a similar price.
(but yea, I'm married to Atmel definitely)

Sooo.... like.... when can we get our grubby hands on an 32 bit powered AxonIII?

[Soeren]

Hi,

The 32-bit AVRs have similar features at a similar price.

Yes, I know, I compare them at irregular intervals. It would be such a downer to miss out on some ways to ease the work flow, just because of "tunnel sight".

It was the piece about them costing $10 I reflected on, but I honestly believe that with such fierce competition, they cannot afford to diverge too much, neither on features nor on price.

The best controller for any person is without any discussion the one that he/she can do the best job at fastest - no matter the name. And when that is said... Unfortunately, it often leads some people to stick to their preferred one and never seriously consider if there might be better solutions, but with a learning curve attached.

[Soeren]

Hi,

Do they have a good, open source C compiler now? :p

I have no idea of what you call good, but yes, I believe there is a few around.
Not that I care too much, I don't mind paying for quality, but I allways hated C, as it is an ugly language (I do have to use it quite a bit though). The only C compiler I have for PICs is a sort of visual C (not the PC kind of "visual") for Rapid Design, where you can start a program design by dragging components onto a form and when done with the rough structures and their setup, you change to real coding.

Anyway, if you only code in a high level language, I don't see any reason to prefer AVR over PIC over something else or the other way around.

[roborg]

Hi,

The microcontroller chip itself costs almost $10 (for higher end ones), and the board costs a few $s, so you probably won't get much cheaper than $30. They really aren't making much .

Gee, is AVRs really that expensive??

This is just one out of a vast range of PIC processors which would be much more than it takes to control two steppers and it's $1.56 in PDIP in one off. Much less could do it (like the trusty 12F675 at $1.10), but this was just a random pick.

Here is one that kicks a bit more butt, 100 pins and 80MHz clock
A bit more of the features:
 USB 2.0 On-The-Go Peripheral
 Dedicated DMA Channel for USB OTG
 512K Flash (plus 12K boot Flash)
 32K RAM (can execute from RAM)
 4 Channel Hardware DMA Controller
 Flash prefetch module with 256 Byte cache
 Lock instructions or data in cache for fast access
 Programmable vector interrupt controller
 Fast and Accurate 16 channel 10-bit ADC,
 Max 1 Mega sample per second at +/- 1LSB, conversion available during SLEEP & IDLE
 2 wire programming and debugging interface
 JTAG interface supporting Programming, Debugging and Boundary scan
 Fail-Safe Clock Monitor – allows safe shutdown if clock fails
 2 Internal oscillators (8MHz & 31KHz)
 Hardware RTCC (Real-Time Clock and Calendar with Alarms)
 2 x SPI, 2 x IIC
And loads more.

One off price $7.59

Damn it must sucks to be married to Atmel   

But these are processors, not boards. I will have build everything else around it. I don't know how to do all that (yet) as I am not comfortable with all electronic components yet. This is why I am looking for a board.

Thanks,
RO.

[roborg]

Hi,

USB port can be used as power source

Will this also power the Stepper motors? USB port power is limited.

If you've got some really tiny ones perhaps, but in general no.

What exactly are you making, with what model motors and what is it intended for?
Controlling two steppers is not a big job, but I assume it should be controlled in response to some outer activity or conditions.
You get better advice when you give us all the gory details.

Hi,

I haven't narrowed down motor models yet, I am hoping to use some old ones. I have 1 uni-polar motor (found at a hobby shop) and 2 bi-polar stepper motors (from old floppy drives) so far. However, I am not able to find specs for those as not much is written on them.

The activity/conditions that activates motors is basically a timer event. Every few mins or so, the program evaluates some logic and decide on how much and which direction to move. This is just to learn how to control stepper motors (as I have them around). So how much, how long, in what direction etc. doesn't matter.

Now about the stepper motor controllers, I looked at http://www.schmalzhaus.com/EasyDriver/ and it is not clear if I need one or two of those controllers and I am not sure if it is worth it.

I looked at the following links:

1) http://www.arduino.cc/en/Tutorial/StepperUnipolar
2) http://www.arduino.cc/en/Tutorial/StepperBipolar
3) http://arduino.cc/en/Reference/StepperUniipolarCircuit
4) http://arduino.cc/en/Reference/StepperBipolarCircuit

Particularly the last 2 links, where there is no controller used to drive the motors. Instead for bi-polar stepper L293D h-bridge is used and for uni-polar stepper Darlington array is used. To connect these circuits, I think I need a breadboard on top of the Arduino, instead if there is something I can purchase (which is probably the stepper motor controller ) and connect my motors on one side and my board on other side, its simple and easy to use, so I can focus more on the programming logic that drives these motors.

Thanks,
RO.

[Webbot]

Hope you also read: http://www.societyofrobots.com/member_tutorials/node/120
and http://www.societyofrobots.com/member_tutorials/node/159