Rip Off... very interesting take on this?  I set the price for the kit at
what it would cost to purchase all the components single quantities.  If I
sold 1000 a week I could probably sell these kits for $13 or $14 and do it
full time.  But that is not going to happen.  I don't want to waste
bandwidth on this thread, but I have to at least defend my kit from the 2
messages to the list stating this thing is a rip off..

At Digikey:

PIC16F877/20: $9.88
MAX232: $1.60
Resonator: $.81
LM7805: $.59
Reset Switch: $.49
Batter Clip: $.29
All other stuff: $.50

That's just over $14.  If you add $5 for a serial cable (I dare you to find
one cheaper at your local computer store) that totals $19.

If you did buy all of this from Digikey you would also have to add $5
handling fee to the order since it totalled under $25.

I figured if I purchase this stuff in larger quantities I might be able to
make some money while saving others some time (see the story below).  It
turns out that I spend about 15 minutes putting this kit together in
programming/testing the PIC, cutting/bending the resonator socket,
stripping/soldering pins to the serial cable, sorting/packing all the
parts, printing the manual, writing the floppy, printing a shipping label
packing it all up.   I have tried to do it faster but it seems to always
take me just about a hour to get four of them ready to ship.   I make about
$7 on each kit I sell.  So the best I could do is $28 an hour and that is
assuming once the kit is shipped out I don't spend any more time on it..  I
only sell about 5 or 6 of these kits a week so that is an extra $35 a
week.  Not really worth the effort and the up front cost of the inventory.

THE STORY

If you don't want to read a long story about how this kit came about I
would just delete this message now.

When I started with the PIC I purchased a 16F877 and a Warp-13 programmer
(very good product by the way) for the heart of a stepper
controller.   That set me back about $100.  Now I could program the PIC,
but I needed more parts to do anything else with it.

I did some searching and determined I needed a crystal, voltage regulator,
some caps and resistors.   I went to radio shack and purchased everything
except the crystal (they had to order that and it would take over a week).
The parts I did purchase at radio shack cost over $5!  I would recommend
you use Radio Shack only as a last resort for anything.

After more research I found that I could use a ceramic resonator instead of
a crystal and 2 caps.    Digikey had the part for less than $1 but they
have a minimum order of $25 unless you want to pay a $5 handling fee.  I
did what any other electronics tinkerer would do and bought a bunch of
stuff I didn't really need to bring my order up to $25.  The parts arrived
in 4 days and I was good to go.

After playing around with MPLAB I realized that I would be doing a lot of
re-programming to get this thing right and I remembered reading about a
boot loader that allowed these chips to reprogram themselves.  I thought
that would be a great idea because I was already planning on using a serial
interface to talk to the controller and I would not need to move the PIC
back and forth from the development board to the Warp-13 while learning how
to program the PIC.  I looked into it further and found the Microchip
application note AN732.  It described what I wanted to do, but used 2
precious pins for hardware flow control.  I figured I would modify it to
use some sort of software flow control after getting the example in that
application note working.

By diving into this boot loader idea I realized, sooner rather than later,
I would need something like a MAX232 to connect the PIC to a PC.  Since
that chip is another part not available at the local Radio Shack I had to
buy another $25 worth of stuff at Digikey to get it.  It arrived and I set
it all up on my breadboard, created a MPLAB project and loaded up the
example code from the AN732.  Well that code did not work at all... It
drove me nuts because I didn't know if my circuit on the breadboard was
wrong or the code was just broken.  I dug into it further on the
net.  Turns out there is much more to serial communication on a PIC than
what is described in AN732.  After many more hours of frustration I finally
wrote serial routines that worked and got the thing to program itself using
software flow control.   I then worked on a simple c-based DOS program to
do the hexfile upload... another 4 hours of work... gotta hate DOS programming!

So after over $150 and many hours of work I have finally had a boot loader
enabled PIC.

When I got everything working I thought this might be a good idea to
package up save others some time.  It was not until after I got the motor
controller done I decided offer all of this work in kit form for a lot less
than what it cost me.

- Dan

At 07:36 AM 6/26/02 -0400, you wrote:
> > Hey, what a rip off.  Boot loaders are free, and its not hard for people
>to
> > find a pre-burned chip with one for a lot cheaper!
>
>There are certainly free ones out there, and it's not even that hard to
>write your own.  We have our own, although we don't give it away for free.
>I suspect he won't get any takers.
>
> > Also, This list is not
> > here for commercial purposes or your own financial gain!
>
>Actually, I think it is allowed as long as it's tagged with [AD], which it
>was.  I'm sure an admin will correct me if I'm wrong.
>
>In short, yes I agree its a ripoff which he will probably discover shortly.
>However, if you don't want these kinds of messages then its up to you to
>shut off the [AD] channel.  I wouldn't want to see one of these every day,
>but for now I find it entertaining.
>
>
>*****************************************************************
>Embed Inc, embedded system specialists in Littleton Massachusetts
>(978) 742-9014, http://www.embedinc.com
>
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