Shop Stuff: March 2011 Archives

ICSP - a meta-CNC project finished!

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Yeah, I can reclaim my breadboard (again)! 

The plan is for my CNC to use a couple of PICs (16F716's to be precise) for stepper drivers. This entails programming them. I built an In Circuit Serial Programmer following instructions on line. It worked, however, my programmer was prototyped on a breadboard. I don't have many of those, and wanted to work on a different circuit.

My CNC is not quite ready for PCB milling, so what to do!?!

A couple handy pages online led to the answer. Tonight I etched my first PCB in many, many years. In the past, this was a royal pain because:

  1. Creating the artwork was tedious.
  2. Laying the artwork on the blank board was tedious.
  3. Etching with harsh chemicals not fun.
  4. Artwork lifting off board is frustrating.
To handle the artwork, I have been working on my Eagle skills. Next challenge was getting the artwork on the board. That turns out to be not that hard. Print the artwork on magazine paper and iron it onto to board! Next, for etching, again household chemicals to the rescue!

  1. Equal parts H202 & vinegar
  2. 1 part salt to 9 parts above mixture.
  3. Mix, add board and etch.
  4. Add more salt if reaction slows down.
(I used lots of salt - my board took a few hours. FerricChloride is faster, but not stocked in my kitchen or medicine cabinet)

No more nasty chemicals or lifting traces - yeah!

Here is the end result:

ICSP board


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Well, in my quest to build a cheap CNC driver I have been learning lots and not saving a whole lot of money.

Today I broke down and purchased the resistors and diodes needed to build a PIC In Circuit Serial Programmer.

The ICSP that I'm implementing is based on the work done by "Nancy".

The good news is the breadboard version seems to work. The software is able to detect the PIC (16F716), claims to be able to program it and even verifies that it has been programmed as requested. (To confirm it actually verified correctly, I stuck a blank in and received an error message when I "verified" it.)

Sadly the PIC didn't do what I wanted it to - it gets to the initial state, but doesn't respond to inputs. There are some warnings in the HEX editor of the PIC that may need attention.

So tonight is a good news / bad news state that I'm going to bed on.

(PS - So far I'm in to this CNC for over $350 - lots of that is education, spare parts and the new Spin Saw which has yet to be mounted.)