Re: Monitor three or more footswitches over RS-232

On Mon, 14 Nov 2005 08:36:20 -0800, AndyCW wrote:

> Potentially I could need 100 of these... but let's start with one to
> prove the concept!
>
> As for polling the interface... well, I code in C# using the .NET
> compact framework, and the serial API has events that fire when data is
> received, and I can trap the events in my code. How they do that, I
> don't know, or care... but it has to be more efficient than me having
> code running in a tight receive loop. One thing I know from years of
> handheld device programming, is you never miss a chance to save battery
> power :-).
>
> The target PDAs are Windows Mobile devices (Pocket PCs) so the serial
> port behaviour is pretty similar to a desktop PC. You can use software
> or hardware flow control and the port characteristics are pretty
> configurable.

I've written an RS232 driver for a PIC12F683 microcontroller. Works
reliably up to 9600, and controls the 'modem signals' for flow control.
The PICs themselves cost around a buck. The PC card, switch setup, and
that sort of thing would run a few more bucks in volumes of 100, but a
prototype would be quick and easy. The device could be powered from a PC
serial port, or just use a battery or wall-wart for power. Powering it
from a PDA would probably not be a good idea...

Email me for more info.

---
Regards,
Bob Monsen

Even the greatest of creations start from small seeds.
- Unknown
.

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