Good for you Rubin -- nice to see someone take some initiative.  Just the fact you got
all the parts together is useful.
David

Daniel Rubin wrote:

> 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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