Ricardo Ponte G wrote:
> I4d like to know if I it4s possible get the power (+5v) from the serial
> port of the Computer.

I have successfully derived sufficient power for small projects by
attaching a diode to DTR, RTS and TXD with the cathode of each attached
to the input of a 5V regulator.  Attached is a small schematic.

I'm not an expert in such things, though.

My electronics engineering friend says "It'll work - as long as they 1/
set the bits to the correct sense with software and 2/ don't take too
much current.  1n914 [diode] is enough for low current"

Serial ports vary.  Some drivers are high impedance and won't deliver
sufficient current.  I wouldn't want to make a product for sale without
testing it against a reasonable number of computers.

--
James Cameron                                      (cameron@stl.dec.com)

OpenVMS, Linux, Firewalls, Software Engineering, CGI, HTTP, X, C, FORTH,
COBOL, BASIC, DCL, csh, bash, ksh, sh, Electronics, Microcontrollers,
Disability Engineering, Netrek, Bicycles, Pedant, Farming, Home Control,
Remote Area Power, Greek Scholar, Tenor Vocalist, Church Sound, Husband.

"Specialisation is for insects." -- Robert Heinlein.
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