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View Full Version : Autonomous servo controller with A/D and RS-232 input?


Arp
May 18, 2005, 04:53 PM
Hello everyone,

Today, while looking for other bits... I accidentally found a programmable servo controller. (It appears suitable for either a failsafe system, or possibly even independent navigation. Cannot tell for sure.)

It is manufactured by a company called Pontech. Its mid-range model SV203B (http://www.pontech.com/products/sv200bc/index.htm) and high-end model SV203C sport the following capabilities:

-- RS-232 communications port
-- 8 outputs for controlling servos
-- 4 inputs with A/D converters
-- EEPROM memory for 8 KB of Basic bytecode
-- ability to execute this code autonomously

Looking at it... I started thinking of projects simpler than a PC. It appears to me... that if some obstacles can be overcome (or worked around)... this device could become a feasible (simple but somewhat customizable) UAV core.

So, what feature am I doubting about? Well, naturally the opportunity of conncting *two* devices to the RS-232 line -- because one would leave the feature set incomplete.

To have *both* autonomous navigation and remote control, one should be probably be capable of connecting the RS-232 interface to *both* a GPS receiver and radio modem.

This *may* be doable... in fact, I have seen two devices kludged together to speak on the same RS-232 line... but those devices "spoke" in turns. A GPS receiver, unfortunately... generally jabbers continuously, and stops at nothing.

So take note: this may be a potential platform... but may also prove an utter failure. (I personally may never know, since I need image processing, and thus use PC hardware -- for my project, this only needs to become an ordinary servo controller with the side benefits of voltage monitoring and failsafe actions.)

Arp
May 18, 2005, 05:17 PM
Oh well... sorry for raising any baseless hopes.

I just consulted its detailed programming specifications... and the picture I saw... was a wasteland compared to most languages.

Only 60 bytes of RAM, does not support floating-point (neither does it support integers of decent size)... and incapable of computing trig functions (cannot divide and multiply, which are sort of necessary for even elementary trig).

If I optimized my mind out... perhaps I could make it parse a *very simple* GPS sentence... and follow hard-coded waypoints... but no way is this going to *autonomously* control anything significantly interactive or smart.

I will, however, still be happy to use some... because this appears among the very few servo controllers which *can* measure voltage.

Crazyrcer
May 18, 2005, 05:56 PM
I'm not sure if this is what you're looking for, but I thought I'd post it anyway. Yost engineering ServoCenter. (http://www.yostengineering.com/index.cgi?section=Hardware&subsection=ServoCenter/main.html)

Arp
May 18, 2005, 06:11 PM
It is similar... like multiple other servo controllers, like Parallax (stands out with 16 channels and TTL level signals, making it immediately compatible with Parallax robot boards), Pololu (features high speed and fine control resolution) and PhidgetServo (features USB). The Yost controller which you found... does handle an impressive number of devices.

But none of the above-mentioned... have one crucial feature which initially caught my attention in the Pontech controller -- namely ability to measure in addition to controlling, and run a custom program.

My only slight disappointment... was that the custom program of the Pontech suffices only for very simple tasks.