PDA

View Full Version : Mini-SSC for mech control



RevBryce
08-11-2009, 07:07 AM
G`day Jim
Love the brat mech so far and with all the talk about weight problems that people
have mentioned elsewhere i have a question.
I have a mini ssc II that i got from lynx years ago and had a thourght that
as my mech has 4DOF per leg is there any reason not to use it just to control them?
Does it work with micros ( i never did do much work with it)
What i think i`m looking to do is use it for the legs and hook the gun and cam servos directly
to the micro.
Any reason not to do this?

Robot Dude
08-11-2009, 09:34 AM
G`day Jim
Love the brat mech so far and with all the talk about weight problems that people
have mentioned elsewhere i have a question.
I have a mini ssc II that i got from lynx years ago and had a thourght that
as my mech has 4DOF per leg is there any reason not to use it just to control them?
Does it work with micros ( i never did do much work with it)
What i think i`m looking to do is use it for the legs and hook the gun and cam servos directly
to the micro.
Any reason not to do this?

You never mentioned what processor you have. In it's day the MiniSSC-II was a great controller. However things have progressed since then. The problem with the MiniSSC is in order to move a servo smoothly and slowly from point A to B you must send the intermediate positions. It can require a pretty good amount of overhead from your processor. The SSC-32 is a huge step up in performance. To move smoothly it requires only a single command modifier.

#0 P2000 #1 P1500 cr <- initialize two servos.
#0 P1000 #1 P1000 T2000 cr <- move these two servos. take 2 seconds to do it.

In the example the two servos are told to move to new destinations. They will start and stop at the same time even though the distance they are moving is different. You can also use a speed modifier if it works better for your application. You can see how this greatly simplifies gait generation, and at the same time take a major load off the host microcontroller. Even if you only need 6 or 8 channels it's still an incredible value at only $39.95.

Another option for smooth servo control is to use the Atom Pro which can emulate a limited channel version of the SSC-32 in the (pseudo) background. This is what we are doing with the BRAT. Once properly set up you can even write programs around the servo code to play sequences and monitor sensors or read a control device such as a wireless PS2 controller at the same time. Hope this helps, Jim

DresnerRobotics
08-11-2009, 10:20 AM
You never mentioned what processor you have. In it's day the MiniSSC-II was a great controller. However things have progressed since then. The problem with the MiniSSC is in order to move a servo smoothly and slowly from point A to B you must send the intermediate positions. It can require a pretty good amount of overhead from your processor. The SSC-32 is a huge step up in performance. To move smoothly it requires only a single command modifier.

#0 P2000 #1 P1500 cr <- initialize two servos.
#0 P1000 #1 P1000 T2000 cr <- move these two servos. take 2 seconds to do it.

In the example the two servos are told to move to new destinations. They will start and stop at the same time even though the distance they are moving is different. You can also use a speed modifier if it works better for your application. You can see how this greatly simplifies gait generation, and at the same time take a major load off the host microcontroller. Even if you only need 6 or 8 channels it's still an incredible value at only $39.95.

Another option for smooth servo control is to use the Atom Pro which can emulate a limited channel version of the SSC-32 in the (pseudo) background. This is what we are doing with the BRAT. Once properly set up you can even write programs around the servo code to play sequences and monitor sensors or read a control device such as a wireless PS2 controller at the same time. Hope this helps, Jim


Have to agree completely here, the SSC-32 is one of the best values on the robotics market. I personally own 5 of the units for various projects (and spares).

RevBryce- There should be a Lynxmotion distributor local to you, I believe you can check their distributor list on their website. If not- we can always ship it to you internationally here at Trossen. I definitely recommend the upgrade though, coupled with the Bot Board 2 and a Basic Atom Pro, its a very solid platform for hobby based servos.

Adrenalynn
08-11-2009, 11:05 AM
[Moved this post to its own thread since it had nothing to do with Jim's mech]

If you have enough channels, you could control all the servos from one board.

by "micros", I assume you have some specific board in mind, and not a restaurant cash register... ;)

Any board that can do serial can talk to the SSC.

I further concur with the SSC-32, but I only have three. :)

RevBryce
08-12-2009, 04:27 AM
G`day again
You guys make me feel so ummm ..you know ummm
As i only have one ssc-32 as well as the mini.
I was just looking to keep weight down and the mini is
so small next to its bigger brother.
ah well.
I havnt decided on a micro yet and most of my programing
lately has been with mega8s so i`m in need of a upgrade.
I do like the bot board and atom idea as they dont look to big.
Thanks for the answers.

mannyr7
08-12-2009, 04:47 PM
Bot Board is the same size and hole pattern as the SSC-32. I bought one with my contest winnings and it should be here Monday. I'll let ya know how that works out. Stay tuned! Oh and don't feel bad, I only own one SSC-32 myself.