Hi, I’m very green to all of this. Total newb. I have a pretty simple need for the SSC-32 and I’m hoping you guys can tell me whether this is the right direction or not.
I want to control 9 servos (possibly a 10th with more needs). I need all 9 servos to move from position a to position b and back again (where a & b are identical distances/positions for all 9 servos) by either button push or switch flip. In other words, I’d like to have a control panel with cheap switches on it for each of the 9 servos, and when I flip servo 8’s switch, it travels from a to b. Flip the switch to the opposite position and have the servo travel from b to a.
I’m looking at other low tech ways to do this too, but these servo controllers seem like they might work.
A little background on this. It’s for a model railroad layout to switch turnouts (switching track). There is a product that does this called a tortoise switch motor. They’re $14 each, so I’m looking at around $140 +/- to use that product. I found cheap servos ($1.99 to $2.99 each), and I thought if I could buy 9 of those and a controller, i’d be willing to learn the controller etc. to save a little money and learn something new. The only thing I’m not clear on is the switching part. Everything I’ve read has to deal with rather complex code etc for robotics etc. using scripts or a prepackaged program loaded on the on board memory to command the servos. My needs are much simpler once I determine what the pulses I need to send are. On/Off…
I’ve got some experience in programming (C, C++, VB plus a bunch of website code knowledge), so I’m pretty confident I can figure this out. I just need to know from people who know the board whether what I want to do is possible before I jump in with both feet.
That’s kind of what I was thinking. In defense of the cheap servo, they’d be put to task moving a tiny piece of plastic that weighs about 1/10 of an ounce about 1/16th of an inch, so I doubt even the cheapest piece of garbage would falter under those circumstances. Accuracy is also moot.
Sounds like I’d be approaching the cost of the off the shelf units. Someone suggested a much simpler low tech way of doing what I need on another forum, so I’m exploring that route now. Thanks for answering though.
You mention C, do you have access to a PIC C compiler?
There are many cheap ($15?) boards for PICs, if you can do a little PCB project. Digikey has plenty of slightly more expensive PIC “demo” boards, or check MicroChip. The code is simple, watch your switches, send a string to the SSC-32 when you detect a switch closure. We can help!
BB2 and AtomBasic are fine also. The 'Pro has a GNU C compiler available also.
You don’t really need an ssc-32 to do what you want. You can make a motor reversing setup that uses switches and limit switches to do the job. Convert the cheap servo into a simple gear motor and use a double throw double throw toggle switch to operate the servo.
Using the little $1.99 servos, I’d just skip using the limit switches and diodes and just use the on-off-on spring to off toggle switches. Reduce the voltage if needed with a pair of diodes so the gears won’t strip when the track hits the end stops. I think jameco has the toggle switches for ~$1.50 each. For the small servos, a 5v regulator chip would probably be just about right for a power supply if batterys are not used.
I am familiar with this application. With servos, you won’t need limit switches. The pulses you send will limit the travel of the servo; if you use a flexible wire as the actuator, it will give a little and hold the points to the rails. There are many schematics available using a 556 timer chip and a handful of parts to make a servo diver circuit. with the $1.99 servo and one of these circuits, you could make your own slo-mo switch machine for well under $10 apiece. I’ve included one below - note its modified from a circuit reference I have and not tested!
Use the two adjustable resistors (trimmer pots) you can set the left and right position of the servo.
Set R2 to 0 and set R1 for one position. The set R2 for the other direction.
