Basic Stamp 2 and SSC

[Venkatesh]

Hello,

I have a question about something from years long past, specifically the 1999 Robot Controller. The 1999 First manual/book/binder/volume/moldy tome provides some information about the controller. One of the facts that they mention is that the User BS2 was connected to a chip called the SSC (serial servo controller). The SSC would then drive both IFI Victor 883 and Tekin Rebel speed controllers.

Right now, I am interested in interfacing a BS2 and a Victor speed controller. I searched the forums and found some materials, which are useful. However, I am interested in controlling multiple Victors with only one signal pin, which was how the 1999 Board worked. If anyone knows what chip the SSC was and how it worked, could you please enlighen me?

[Rickertsen2]

This will suit you http://www.hvwtech.com/pages/product...p?ProductID=48

I wasn't around FIRST in 99, but it sounds like you are describing this guys predecessor. Its basically another preprogrammed microcontroller that takes serial commands and outputs servo signals, saving you the programmign and IO pins of outputting the signal yourself.
BTW how many victors are you looking to drive, and how many pins do you have available? There may be better options.

[Random Dude]

Originally Posted by Rickertsen2

This will suit you http://www.hvwtech.com/pages/product...p?ProductID=48

I wasn't around FIRST in 99, but it sounds like you are describing this guys predecessor. Its basically another preprogrammed microcontroller that takes serial commands and outputs servo signals, saving you the programmign and IO pins of outputting the signal yourself.
BTW how many victors are you looking to drive, and how many pins do you have available? There may be better options.

Ya, that was what was in the 1999 vintage controller. At one point I helped my team build our own copy of the FIRST controller, and it used almost that exact part (minus the board, I believe). Though unfortunately, they switched to the IFI controller shortly there after. (Though they started letting us keep the controllers as well)

[Sparks333]

How's this?
Try clocking the signals though programming. Put one Victor signal on the top of the first clock, then another on the top of the second, and so on. That is the only way I can think to get several Victors on a single signal pin. In short, do it in serial, as opposed to parallel, which is what you are doing.

The way to separate those signals is to syncronize a 5-stage Johnson counter with the FIRST controller. A 5-stage Johnson counter will take in a signal, send it out one output, then on the next clock, will send the next signal out to another output, and so on and so forth. It sounds like you want to use a serial system to control a normally-parallel system, so the johnson counter is required to separate the signals. It's the same system used by recievers, since the servo signals come from the transmitter in serial format, then is sent to the respective servo in parallel.
Hope this helps! It would be hard to program, but easy to do electrically. Using this particular system, you could control 4 or 5 Victors on a single pin. You could do 2 if you did a flip-flop based system.

-Sparks

[Astronouth7303]

Is a stamp fast enough to do that? it would seem like all you would be doing it is flipping the pin on and off at the apropriate millisecond. You may be able to do it using a PIC (w/o IFI's overhead) in assembly, but as far as a Stamp goes, I'd get some dedicated hardware.

[Andy Brockway]

Parallax has the PWMPAL and their own Servo Controller that would work. I am currently using a Mini SSC2 that I got from Mondotronics on a small project at home. It will handle eight speed controllers and/or servos from one command line using SEROUT commands. This may be the easiest solution.

[Adam Y.]

Parallax has the PWMPAL and their own Servo Controller that would work. I am currently using a Mini SSC2 that I got from Mondotronics on a small project at home. It will handle eight speed controllers and/or servos from one command line using SEROUT commands. This may be the easiest solution.

Yeah but I always though Victors don't work with standard R/C equipment and the PWMPAL is designed to control servos which use standard R/C signals.

[sanddrag]

If I remember correctly the PWM Pal outputs a sine wave signal and what you need to drive a Victor (or most speed controls) is a square wave signal. On most speed controls a pulse width of 1.5 ms is neutral 2.0 ms is full forward and 1.0 ms is full reverse.

I have a project on which I am driving a RoboWars IBC speed control (a really nice and fairly inexpensive unit I might add) directly from a BS2. All I needed to do was use the PULSOUT command and it works absolutely perfectly. I have also tried it with a Novak Super Rooster speed control meant for RC cars and it worked perfectly. I don't see why it wouldn't work with a Victor but I have never tried it.

[Adam Y.]

I have a project on which I am driving a RoboWars IBC speed control (a really nice and fairly inexpensive unit I might add) directly from a BS2. All I needed to do was use the PULSOUT command and it works absolutely perfectly. I have also tried it with a Novak Super Rooster speed control meant for RC cars and it worked perfectly. I don't see why it wouldn't work with a Victor but I have never tried it.

There are two versions of the victor. The victor that we don't use is designed to accept r/c signals. The other victor as far as I knew never used standard r/c signals which is why it can't work with r/c equipment. It even says it on the innovation first website.

[Billfred]

Not quite...

According to IFIRobotics.com (Innovation First's un-FIRSTy site), a Victor is a Victor is a Victor. However, they have a PWM signal driver which they recommend for any non-Issac (to us, the pre-2004 OI and RC) control systems. But they all use PWM signals.

[Adam Y.]

According to IFIRobotics.com (Innovation First's un-FIRSTy site), a Victor is a Victor is a Victor. However, they have a PWM signal driver which they recommend for any non-Issac (to us, the pre-2004 OI and RC) control systems. But they all use PWM signals.

I never said they didn't use PWM. All I knew is that the PWM signals aren't compatible with r/c radios. So all you need is the ten dollar signal driver and you should be able to control victors with the servo controller. End of story.

a Victor is a Victor is a Victor.

Actually if you look closely the victors of ifi's site isn't the victors we use. I was trying to figure out why the victors were about 30 dollars more expensive then the ones we use. Aparently they support 24 amps. There are about four differnt brands.

[Andy Brockway]

I do not know everything about PWM or why IFI needs a driver to interface with some r/c equipment. I did hook everything back up (BOE with BS2sx and IR detector, Mini SSC2, Victor 883, HiTec HS-311 and TV remote running Sony Protocol) to test and verify what I do know......

PWMPal, Mini SSC2, Isaac's, FIRST RC's all put out the same PWM. The basic stamp can put out a type of PWM using PULSOUT as sanddrag mentions above. The pro side of using the hardware is that the hardware will run independently after receiving a command letting the BS run the rest of its code. This is what the FIRST RC's do. The main processor runs your program and downloads the PWM and relay values to a secondary processor. This is done through the SEROUT command when we were running PBASIC.

Good luck with your project!

[Sparks333]

Andy,
I think the IFI needs a driver to interface with saw-tooth waves, a standard in RC cars (I think this is right...?) as opposed to a square wave, the standard PWM output.

-Sparks