Hi:

I'm in a similar position as you (i.e. poor student) and I went through
quite a phase of building different programmers trying to find one that
works.  I had the best luck with Pic-Programmer 2 (aka the JDM programmer).
 It is powered by your RS-232 port, and takes no special components (a
couple of transistors, two zener diodes (5.1V and 8.2V), four regular
diodes, and two capacitors) and I can definitely say that it does work (at
least for 16F84s in my experience).  The Pic-Programmer 2 schematic can be
downloaded at http://members.tripod.com/kizzyblizzy/pic2.htm.  You'll
probably have to change the socket pinout on the schematic to suit the
16F873.

For software, I use IC-Prog which can be found/downloaded at
http://www.h2deetoo.demon.nl/.  The software is Windows based and very
intuitive. The documentation claims it supports all PIC 16/17 series MCUs
(along with dozens of other devices), but I haven't used it specifically
for 16F873s yet.  Perhaps someone who has used this hardware/software
combination can vouch for it.

Hope this helps,

Chris Robertson.

On Wednesday, April 05, 2000 1:04 PM, chunhee song
[SMTP:chunhee@LPL.ARIZONA.EDU] wrote:
> I am in same situation here. I want to build a cheap programmer for
> pic16f873. I am a penniless student and don't afford to spend money on
it.
> Does anyone can help me???
>
> Thanks a lot
>
> ----------
> > From: johan strombom <johanspiclist@hotmail.com>
> > To: PICLIST@mitvma.mit.edu
> > Subject: Re: COM84 programmer
> > Date: Thursday, April 06, 2000 11:33 AM
> >
> > Hi!
> >
> > I can't believe it would be very hard to use the "Extra low cost pic
> > programmer" (http://www.jdm.homepage.dk/newpic0.htm) with a pic12C508
> > instead, the only problem is that I have no idea about the pin
> configuration
> > for this device. Does anyone know if it's able to build a similar
> programmer
> > for pic12C508, and how? I'm also interested in a simple programmer for
> the
> > pic16c74b.
> >
> > /Johan
> >
> >
> > >From: Stan Ockers <ockers@ANL.GOV>
> > >Reply-To: Stan Ockers <ockers@anl.gov>
> > >To: PICLIST@MITVMA.MIT.EDU
> > >Subject: COM84 programmer
> > >Date: Thu, 6 Apr 2000 07:35:05 -0500
> > >
> > >                             Subject:                        Time:
> 7:06
> > >AM
> > >                             COM84 programmer
> > >4/6/00
> > >                                                              Date:
> > >After using a parallel port programmer for quite a while, I recently
> > >switched to a simple serial port programmer to program PIC16F84's.
 The
> > >programer uses few parts, is easy to use and best of all, needs no
> external
> > >power supply.  The programmer I'm talking about can be found at:
> > >http://websites.ntl.com/~matthew.rowe/micros/
> > >Click on 'Start' under PIC and then 'build the programmer'.
> > >The software I use is called PIX and can be found at:
> > >http://home5.swipnet.se/~w-53783/
> > >Click on 'download PIX113b.zip'
> > >
> > >Since this programmer is so convenient, is there any reason not to
> prefer
> > >it over a parallel port programmer?
> > >
> > >I built the programmer using 1/2 of a Radio Shack Dual general-purpose
> IC
> > >PC board, (276-159).  If anyone is interested, I can make up a package
> of
> > >description and pictures.  Contact me off-list if you are interested,
> (
> > >  ockers@anl.gov ).
> > >
> > >Is there a chance someone might create a similar design for the
> PIC16F87X
> > >series soon?
> > >
> > >Stan
> >
> > ______________________________________________________
> > Get Your Private, Free Email at http://www.hotmail.com