PURPIC, the wearable PICkit2 clone

One of my very first Instructables was a stripped down PIC programmer based on a design by David Tait using through hole transistors and resistors glued to a piece of cardboard. Oh, how times have changed. And as usual, I'm still 7* years behind those changed times. My latest project is a remake of today's hottest 7-year-old PIC programmer, the PICKit2!

*there, fixed!

Step 1: An extremely brief history of the PICkit2

Microchip launched the PICkit2 in 2005. It is a hugely popular device that programs and debugs a wide array of PIC microcontrollers and EEPROMs. Even though it has long been superceded by the PICKit3 and the ICD3 programmers, there are still a variety of features which make the PICKit2 quite useful (and cheap) for specific applications.

In addition to working with Microchip's MPLAB IDE as both a programmer and debugger, Microchip also created a nifty standalone software for the device which is very easy to use. There is a Widows GUI version and also a command line version of the programming software. The engineers even added a "programmer-to-go" functionality, which allows the PICKit2 to burn chips with no computer at all. So even though the PICKit2's MPLAB debugger is painfully slow, all those other features are quite useful for low volume batch programming on a budget. So even though I celebrated the PICKit2's 7th* birthday by buying an ICD3, it will never make my PICKit2's obsolete.

Comments

[cody305]

I have no idea what these little programmable chips and stuff are used for, do you build robots with them? Build your own cell phone? What kinds of things can you make that would be worth all this trouble? Or do you just do it for fun like a hobby? Thanks!

[TDWay]

AC freezing up is an easy fix , go to the automotive parts store buy a refrigerant refill kit, around $34.00 USD with the engine turned off just add refrigerant (134A)
Connect it to the large AC Line, 1/2 a bottle by weight maybe a little more.
for best results take your car to a garage and have them charge the AC unit.

[klee27x]

That's a good question. Microcontrollers are a computer on a chip, complete with integrated memory, digital and analog I/O's, timers, PWM modules, and all sorts of neat things.

Microcontrollers control the stuff you have all around you. It's not just cell phones and robots. They also control the mundane things that don't take an EE degree to make or modify. I'm talking about elevators. Microwave ovens. Carpet cleaning machines. Coffee makers. They're even appearing on such things as heat guns and other power tools, to provide information such as temperature and battery life.

So... you could make you own microwave oven, carpet cleaning thingy, coffee maker, etc. Or you could modify the above to work more like you envision, rather than how someone else decided you might like it.

You could use them for such mundane things as making a simple on/off toggle switch! I have used dozens of microcontrollers to do exactly that. Why? Cuz combined with a tiny MOSFET, you can control a lot of power at the touch of a tiny microamp button that will fit anywhere, and the micro will draw practically no power when it's asleep.

Some of the things I've done with microcontrollers are viewable in my other Instructables. I've used them to make an LCD display temp-controlled soldering station. And a heat sealer that uses just one push button for both operation and for programming the impulse delay. (That firmware also makes for a great programmable delay fireworks igniter!) And of course, you may also see where I used one to make a simple toggle switch on a small LED flashlight.

One of the things I'm currently envisioning is a lab power supply and soldering station combo, using a single encoder knob to adjust PWM-controlled voltage, current, and soldering iron temperature, with 4 programmable saved settings on the power supply, and all the info displayed on an LCD display.

Lots of today's IC's are even designed with features that require a microcontroller to take full advantage of. The LT1308 I used for the DC boost on this programmer is one example. It has pins on it that are designed with the purpose of providing a low battery warning to a microcontroller.

If you've ever heard of the Arduino, then there you go. Anything you can do with an Arduino, you can do with a single chip. The Arduino just has extra stuff on it that makes it easier to use for a beginner, quicker to develop stuff for the veterans, and easier to share with other hobbyists. It's wonderful. But sometimes, all you want is a 50 cent power switch circuit that fits on a dime.

A microcontroller can also replace logic chips (albeit not quite as fast in many cases). The computer that landed men on the moon was built using something like 50 logic chips. That could be done on a single high speed microcontroller, today.

[cody305]

You just gave me an idea for an application for these. When I have my car A/C on with the blower on low speed, eventually the evaporator coil freezes up and I get no air coming through. Then I have to turn of the A/C compressor switch until the blower melts away the ice and I can get cold air again. If i had an automatic switch that turns the compressor on and off, say five minutes on, and one minute off, but variable time for both on and off, that would allow me to fine-tune it so it would never or rarely freeze up. Is that something a microcontroller could do? Are there existing designs for a circuit like that? What would it cost for all the parts? Thanks!

[klee27x]

Yeah, that's something a microcontroller can do. I think that might be overkill, though, for someone that doens't know how to program one. A 555 timer chip could do much easier for the uninitiated. Google "555 timer chip" and you'll see what I mean.

Hmm. Try this. Use a comparator to turn the coil on/off based on temp. Put a thermistor as one half of a voltage ladder onto the coil. That goes to one input of the comparator. Then put a potentiometer on the other input of the comparator. Now the coil automatically cuts off when it gets too cold, and you can adjust the cutoff with the potentiometer.

Course, you need to use the output of the comparator to drive a transistor that drives a relay, which disconnects power to the coil.

The hardest part about working on a car is identifying and getting to the right wires!

[Kitten Kaboom]

I call that last picture (it occurs with relative frequency among my cats as well) "Syncroni-kitty".

[ildegiron]

That picture really scares me at the thought of kitties scratching the couch with their nails = (

A nice pic indeed.

[klee27x]

I have long given up on worrying about that kind of thing. Cats will be cats. They are incredibly resistant to learning what I wish they would or wouldn't do. And I have decided they make me happier than nice furniture or security deposits. :)

[wbond1]

I have a question, can this device extract a program from an eeprom? I have a collection of about 11 eeproms from the mid 80s that we have lost the program to and we need to extract it, but don't know how or where to go to have it done, can you help me with this please.

[klee27x]

According to my PICKit2 software device list, it can read the following EEPROM families:
11LC
24LC
25LC
93LCAx,C
93LCBx,C

I have no clue as to the amount of standardization between different EEPROM manufacturers or between different decades. I hope you have the datasheet for your parts? And that the parts aren't read-protected?

I wish I could be more help, but I don't have much experience using EEPROMS from this decade, let alone from the 1980's. :(

[ciroman]

" My latest project is a remake of today's hottest 15-year-old PIC programmer, the PICKit2!"
"Microchip launched the PICkit2 in 1997."

Umm...

Launched in 2005?

[Davak72]

Yeah, I don't know where the 1997 came from. Here is wikipedia on the subject:
http://en.wikipedia.org/wiki/PICKit#PICkit_2

[klee27x]

Hmm. Yeah, I dunno either. Thanks for the heads up, guys. I have amended the Instructable.

This is good news! I'm only 7 years behind. At this pace, I should have my first smart phone before the end of the decade. :)

[Davak72]

Haha awesome.

Also, great instructable! The tip about denatured alcohol for hot melt glue will certainly come in handy! (I find it very easy to mess glue up)

Also I read your breadboard ible. When I got my breadboard, the first thing I did was take the back off and connect all the power bars to the screw connectors built into the top of it. It was nice to see I wasn't the only one not wanting to repeat connections that are used all the time. But now I'm going to have to make some of those leds with the smd resistors on the small board!

Thanks for the tips,
David