Hi, I'm relatively new to robotics and had a few questions about one device in particular.
Here's a little background, just to give you an idea of my experience/knowledge. I've been interested in electronics and robotics for a while, I just haven't had much formal education in either subject. I've taken a robotics course in college which I thoroughly enjoyed, and I've played around with some of the Lego Mindstorms stuff a bit. I'm still learning about electronics in general, so please bear with me as I muddle through some of this.
I've had plenty of ideas over the years, but only recently have been motivated enough to give some of them a try. One thing I'd like to attempt is to play around a bit with the idea of home automation/security. Someone suggested I check out Phidgets, so I did.
I recently bought a Phidget LCD Interface Kit, along with a few assorted components to play with. These included some simple analog sensors (light and heat) as well as some digital inputs and outputs (switches and LEDs). I haven't programmed anything yet, I've mostly just played around with the sample code that allows a user to monitor the inputs and toggle the outputs. And, of course, I've tooled around with sending messages to the LCD display. Altogether, it looks to be a nice little system.
Another component I got was a small DC motor (well, two of them) off the TrossenRobotics.com site (which I see has been updated since I ordered). These were for a project I have in mind and I'd like to give it a shot. They were small 574:1 16mm motors which may or may not (hopefully MAY) be of use in my project:
Which brings me to my questions (sorry for taking so long to get to them). I wanted to use the 8/8/8 interface to be able to control these two motors. Nothing too complex, just turn them on and off from time to time (a pretty tame duty cycle), reverse direction, maybe control speed, etc. I picked such a low-speed gear ratio (574:1) because I wanted very fine control of the motors and what they would manipulate (think: telescope automation).
I was wondering how to control these motors. At first, I thought I could use a regular ol' SPST relay for turning the motors on and off, while a DPDT relay could control the forward/reverse aspect. Then I got to talking to a co-worker who told me of the magic of transistors and how THEY could help me. To make it even cooler, he told me about how opto-isolators would let me do the same thing, without the risk of screwing up my interface kit.
Eventually, he mentioned "motor controller" and I remembered something I saw on the site. The Scorpion Mini DC motor controller looked like what I needed. While it might be fun to build my own, I think I'd rather not reinvent the wheel and just use soemthing that is already well-established.
So (finally), here are my questions in regards to the Scorpion Mini controller:
What does the controller plug in to? It looks to have a three-wire lead to it, does it connect to an analog sensor port on the 8/8/8 interface kit? Or would I need some special device in order to control it using the same software that talks with my interface kit.
This is probably an dumb question, but would the controller allow me to simply turn on and off a small DC motor?
A slightly-less-dumb question: would I be able to use the controller to reverse the direction of the motor?
Could I vary the speed of the motor? I don't know if this could be acheived by simply pulsing power to the motor or if there are fancier methods.
I'm assuming that I would use a separate power supply (a rechargable pack or 9-volt battery or something) to power the motor. Is this correct?
Is there any risk of damaging the interface kit through (mis)use of the controller? I wasn't sure if it used some kind of isolator or something.
Could I use the controller to operate a solenoid instead of a motor? This might be a moot question, as I suppose I could just use a simple relay for that.
Is there a file I could download to read up more on the controller? I apologize if I missed a link to it on the site.
Sorry if this post is a bit long-winded, but I tend to do that a lot. I figure I'd rather over-explain the situation (if resources permit) and give people too much information, than to be too vague and have to go back and forth on stuff.
Anyway, I hope I haven't bored anyone, and I really hope to hear feedback from people. I like the Phidgets products so far, the site is pretty well-put-together, and it looks like you have a nice community here on these forums. Also, if I managed to post in the wrong section, please feel free to move this to a more appropriate place.
Thanks in advace!