All,

 The only problem I have with the scenario at the bottom of the page is that
 I don't believe that 3AH for a double A battery (cell) is accurate.  I
 would think maybe half of that would be a good estimate.  But even given
 this reduction in cell capacity, the longevity is still good.  

 Just my 2 cents worth.


                                              Regards,

                                                Jim

 




> Bob Axtell wrote:
>> Portable PIC Programmer
>>
>> Similar to what Tony Nixon was trying to do with his
>> "Pocket Programmer", there is a market for a truly portable
>> PIC production programmer. The market is not only production
>> but also field service (to make field updates). I believe this
>> market can be as large as $USD 100K the first year,  at a cost
>> of $200ea, and become $USD 1M+ within 3 years.
> 
> I have thought of this too, but I don't see the market anywhere near
> the size you do.  If I remember right, Tony Nixon's pocket programmer
> was a commercial failure.
> 
> At $200 each a reasonable profit is possible, but this would have to
> include a nice plastic case, etc, all which make the up front
> development costs higher.  And even if your market estimates are
> correct, that isn't going to be achieved by selling on a
> hole-in-the-wall web site.  That means there is significant work
> envolved in setting up and managing all the resellers.
> 
>> It must be able to be loaded from a USB port on a WinXP laptop,
>> data stored in smaller SD card, storing at least 32 files.
> 
> Or just a flash chip, since the user never removes the memory anyway. 
> They manage whatever the programmer stores via the software and the USB
> interface.
> 
>> To be easy
>> to control, it probably would need a 2 x 16 LCD display. Needs to  be
>> NiMH powered, with built-in charger which can accept walwart or
>> automotive charging source.
> 
> Think about the total joules needed for a programming session.  I think
> you can get a lot of programming sessions from a pair of single use AA
> batteries.  If someone wants rechargeable, they can use AA NiMH with a
> external charger.  Keep it simple.  I doubt anyone would not buy it
> because it accepted just AA batteries without a integrated charger.
> 
> Let's do a quick check.  Let's say pessimistically that 500mA would be
> drawn from a pair of AA batteries during programming.  That's a lot,
> and would only happen if significant target circuit was powered along
> with the PIC. I'm specifying 100mA Vdd for the USBProg and it isn't
> percieved as a limitation.  Of course that 500mA at 3V would mean
> significantly less Vdd current, but still a substantial amount.  I
> don't remember what the rating is for modern one-time AA batteries, but
> probably 3Ah is conservative (you can get NiMH cells close to that
> already).  That means a pair of AA theoretically has 6 hours
> programming life.  Let's further say
> pessimistically that each programming operation takes 1 minute.  That
> means a pair of AA in theory is good for 360 programming operations. 
> Even if it's only 300, that's a lot.  Changing the batteries once every
> 300 programming operations is unlikely to scare off too many customers,
> and there is no charger to loose, and no charing circuit to incorporate
> and pay for and find space for.
> 
> This is not a good application for NiMH because of their high
>self-discharge.  This programmer is the kind of thing that gets banged
>around in the bottom of a field service kit and possibly forgotten for
>months on end until it's needed right there right away.
> 
> As I said, I've thought about this before too, including a design for
> it based partly on the USBProg.  If you really believe this is a viable
> product, are you willing to invest in it and then share in the profits
> later?
> 
> 
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