Monday, February 20, 2006

Haptic: Ethernet solutions

I fired up my old Pontech SV203 servo controller. It takes serial (RS-232) input to control a bunch of servos, and also has five A/D converters on board as well. After going through pain trying to get my VB6 compiler working with the PC serial port on my Win98 art box, I decided to bite the bullet and load up Python (to some extent because my wife is learning Python right now). Adding on the Python Win32 Extensions and then the PySerial module, I finally was able to talk from Python to the SV203 servo controller.

I found a great deal on a Wiznet serial to Ethernet gateway, but then came the surprise that the SV203 isn't made any more, and I need to have one on each side of the network connection for the haptic interface to go across the Internet.

So that leaves me looking at Ethernet-enabled microcontroller boards. If I continue in the PIC direction, there is a board from Modtronix with Ethernet, RS232, many digi I/Os, and 5 A/Ds. To program this board, I'd have to learn PIC C. I know C, but using it to control a PIC is a bit of a learning curve.

On the other hand, there is also the RVHE board, which is programmed in a simple BASIC. Besides Ethernet, it has 6 A/Ds, 26 digi I/Os, and two PWM I/Os (though I'd still need to program my own using the digital I/Os if I wanted to control 5 servos). It costs more, but I am sure the development time would be much less. Supposedly it can do 500,000 BASIC instructions per second and is interrupt driven, so I should be able to control 5 servos in addition to everything else. I've never heard of this board before, it must be pretty new. It is more expensive than the PIC Ethernet boards, but probably worth it.

1 comment:

kenmiller said...

Is the new ethernet you found is much better than the Pontech SV203 you used.

Ethernet Converters