At 10:59 PM 10/7/97 -0500, you wrote:
>Ok, I am looking into the world of electronics and I really like doing
>this sort of stuff.  Let me warn you...I'm only 16 and you're probably
>thinking I should have some socializing to do or something, but...well you
>get the point.

Hey, I'm only 17 and I've been involved with electronics for several years.
Been an amateur radio operator since I was 11. Glad to see more people my
age on the piclist. For me, the piclist has been an invaluable resource.
Since being on the piclist (abt 1 year) I have learned more electronics
than in the previous two years. Socializing can wait, read the piclist and
build fun stuff :-) (The Nerd's Creed)

> I have purchased a basic stamp and constructed the
>programming mechanism for it and have built several of the application
>note projects as well as some of my own.  This included the serial A/D
>which I was very proud of because I interfaced it to my calculator (HP
>48G) (sorry about that, I just had to tell someone about that who might
>somewhat appreciate it).

Sounds like a really interesting project.

> Anyway, I have been looking at other
>microcontolers, and I have been thinking about purchasing a pic
>programmer.  If I do get one, what would you guys (and gals, gotta be
>P.C.) recommend
>that I get, I have been searching around web sites, and I found some good
>stuff at ITU technologies, one of them being a "Warp 3" programmer that
>claims to program everything (for around $130) and a less expensive one
>that doesn't program
>those exotic ones like the 14000 and what-not ($50).

I like the advice given by the others on the list. I have a little $50
programmer that will do most of the 16xxx series pics but since I have
wanted to experiment with the 17xxx and 14xxx seriesl, as well as the
16c5xx so I wished that I had a more universal progammer. If you want to go
the route of the cheap programmer, I would think that you ought to build
one. You obviously have the necessary experience and I have a friend who
built one for about $2 and it does most of the PICs($2 because he had some
parts in his junk box, about $15 from scratch)

> Any hoo, I was also
>wondering, do all of the pics have a serial out command (like pbasic's
>serout), because if I get the cheaper one, it will only program 18 pin
>chips, which according to Digi-Key, none of them include these serial
>features. I HAVE to have that feature.  Digi-Key is real vague with some
>of these things if you know what I mean.  Then once I get a programmer,
>what pic should I use?  I am somewhat attracted to the ones with the
>A/D converters on them just because I use a lot of sensors in my
>projects (I.E. hall effect transducers, mics, this neat-o thing
>called a pulse amplifier, I rigged up one of the school's pH probe
>to my calc set up, etc.). Well, as seasoned picers I'm sure you
>might have a little advice and I would appreciate any of it.
>
>sicerely
>
>Jonathan
>

No, you need to implement your own serial output, but it is seriously not
that hard, besides, we nerds like to do things ourselves, not use other
people's designs, right ? :)

The 16C71 is a nice little pic with 4 channel A/D. Only problem is that u
need an eprom eraser (Like the datarase II sold by digikey for $40). If you
have got an eraser, using a pic like this in not that difficult or painful.
You will need to buy the -JW suffix part for the windowed(non OTP) part.

I would say that for many types of sensors, if only rough accuracy is
necessary, you could somehow turn the signal into a digital signal and
therefore use just a 16C/F84

One example is using a capacitor and resistor on a 18F84 input pin to
create an A/D converter. The cap will take a different amount of time to
charge depending upon the current, which depends upon the voltage because
of the resistor. This is not that accurate(temperature variability, etc.)
and requires an internal logarithmic algorithm to get the optimum accuracy,
but it is a cheap, neat little solution. Other examples would be a circuit
to rectify,filter, amplify, and limit the output of a mic so that a PIC
could tell if someone was talking or not. The moral of the story: most of
the time an A/D is not needed and you can use a 16C/F84

Good luck and looking forward to hearing more from you on the list,

Sean


Sean Breheny,KA3YXM
Electrical Engineering Student