Hi all,
I’m a beginner in robotics and just purchased a micro ssc. how do I interface it with my laptop. Do I need to purchase a special connector cable to connect it to my laptop? Also once its connected, are both the controller and my servo being powered by my laptop? This may seem very basic but as I said, I’m a beginner. Thanks
Damola
Hi Damola,
Don’t worry about asking basic questions, that’s how you find out basic answers!
First off, how you interface the uSSC with your laptop will depend on weather or not it has a serial port. If it does, you will need to connect just two of it’s nine pins to the uSSC. There isn’t a special cable you can buy, but you can cut up any old serial cable to get at the two wires you need.
The serial port and/or the cable you cut up should have little numbers printed by the pins. Pin 3 of your laptop serial port is the RS-232 transmit line, and should be connected to the RS-232 Serial Input pin on the uSSC. Pin 5 is ground, and should be connected to a GND pin on the uSSC (like the one next to the RS-232 Input Pin).
If your laptop is lacking a serial port (as so many are these days) then you will need a USB to Serial adapter, like this one from Pololu. How you connect an adapter to your uSSC will depend on exactily what kind of adapter you get, so lets deal with that later.
As for power, you will need one or two sources of it, one to run the electronics of your uSSC, and one to actually power the motors. The electronics need 5V to 16V connected between the VIN pin and ground, and the servos need 4V to 6V connected between the servo power pin and Ground. You can actually use one power source between 5V and 6V to power both the servos and the electronics. You can either connect this source to both sets of power pins, or just to the servo power pins if you also connect the Vcc=Vs pins.
If that’s not completely clear, I made this little graphic for a previous post:
Your power source/sources can be battery packs or plug-in ac-dc adapters. If you’re using a USB to Serial adapter that gives you access to the USB 5V bus (which the Pololu adapter does) you can use that to power the electronics of the uSSC, but USB can’t really provide enough current to drive the servomotors, so you should still have a separate source for that.
Okay, I hope that answered more questions than it raised!
-Adam
Thanks Adam. That was very helpful. Actually I bought the USB to serial adapter coz my laptop doesnt have a serial port. It was the same one on the link you provided. So how do I connect the adapter to my uSSC. Thanks once again.
Damola
Clip-art is worth 1000 words:
-Adam
Thanks soo much Adam. Your help is really appreciated. Do I need any sort of software I need to download to run or test my servos? If yes, is there some kind of link I can get it? Or is there any link you can recommend for me to learn more about the programs. Once again, I appreciate you help. Thank you.
Damola
I think most people who use these servo controllers write their own control programs using the serial protocol in the user’s guide. I’ve seen/heard of people writing their control programs in c, c++, c#, visual C and C++, visual basic, java, python, labview, matlab, and I’m probably forgetting a few languages (not to mention coupling Pololu servo controllers with microcontrollers).
If you’re into C programming, Pololu has a sample project here. I’m actually not too fond if it, since it’s basically written for Linux, and relies on a linux-line environment called Cygwin to work in Windows
Correct me if I’m wrong, but I’m assuming you’re using Windows. If you are, I wrote a console servo control program in C, and you can download the source code here.
If you just want to verify functionality of your servo controller, you can open up the (virtual) serial port in a terminal program and actually type in the commands (not in ASCII).
If you’re looking for a quick and easy way to test your servo controller rather than a framework for writing your own control program, a couple of people have written nice GUI control programs for Windows. This one from GPSBots lets you drag slide bars to move your servos. If you get an error message when you try to run it, download this file, and unzip it to “C:\Windows\system32”. If you want to see how it was made, the source code and Visual Basic project are at this page.
I haven’t tried it yet, but someone just posted a program they wrote called Animaltronicks a couple of days ago, which should let you set define and run servo motion sequences. I just saw the post this morning, and I’m really excited to try it out!
-Adam