Finished another PCB for the Viscometer

Well, as far as viscometers go, I could be considered an expert by now (no, not really). Today my new board arrived and I assembled it, I’m kind of proud of it, it works real slick just like the last one. This one has the following changes

  • ICSP provisions so that I can program it in place.
  • a PIC18F2620. Has 10 times the program memory and RAM.
  • diode protection in case the power is hooked up wrong.
  • Fast recovery diode for motor induction absorption.
  • Larger traces for the motor.
  • Fixed resistor array.

Anyways, here is a comparison shot. Old on the left, new on the right.

click image for large size

Well there you have it!

A note about PIC MCU’s

Since I couldn’t see a cross reference list about PIC MCU’s between the 10F 16F 18F and 18F(80TQFP), I’ve decided to list it here in all it’s glory. I’ll add to it ass I use more MCU’s

PIC10FXXX PDIP Pin 8 Pin 7 Pin 2 Pin 5 Pin 4
PIC16FXXX PDIP Pin 4 Pin 20 Pin 1 Pin 19 Pin 18
PIC18FXXX 40-PDIP Pin 1 Pin 12 Pin 11 Pin 40 Pin 39
PIC18F 80-TQFN Pin 9 Pin 11,31,51,70 Pin 12,32,48,71 Pin 47 Pin 52
PIC18F 68-PLCC Pin 16 Pin 68,19,36,53 Pin 20,37,49,2 Pin 48 Pin 54
PICKIT 2 Programmer Pin 1 Pin 3 Pin 2 Pin 4 Pin 5

The lamp I’ve been saying I was going to build

Well, I’ve built it, the useless yet fun, timer lamp. The idea behind the timer lamp is to have a bedside lamp that you can turn on and of but also set it to turn off after a certain amount of time. This task is pretty easy but I wanted it to be controlled by a micro controller. After two years of thinking about it I finally got off my duff and built it.

Here’s a blow by blow of how it was built.

Controller board

First I took the thing apart. The wire itself is pretty tough to chew on so I kept it in there so I can save the lamp itself. The lamp was bought from Wal-mart for about $18.

Controller board

Here’s a blurry pic of the control board I designed. It’s generic in that it can take both digital and switch input and output 200ma per channel on 3 outputs. It’s nothing special but it’s small enough and it works. The MCU on it is a PIC16F505, not a great MCU but it works.

Lamp Husk

with buttons

And here’s the casing on the base. Inside was some sort of bizarre weight made of something I did not want to cut.  I took the guts out and popped two 5/8 holes for the buttons. I didn’t have a proper drill so I used a forstner bit, not ideal bit it worked surprisingly well.

ugly guts

I inserted the guts of the machine and had to follow the existing wire in and keep the controller towards the front. As you can see, it’s pretty ugly, as well I used hot glue to affix the boards to some wood which was then affixed with hot glue to the inner casing. It’s not an ideal solution but it relieves me of having to use bolts and it was fast.



And there you have it, it seems to work. No fire, or smoke and it works as programmed (kind of). Now I’ll have to go to work and build a new base, one to keep the unit steady, also I think I’ll add a little piezoelectric tweeter for audible confirmation of time selected.

Anyways, I’m glad I made it this far on the project in such a short amount of time.

Got the PCBs Back!

Well, they turned out about as good as I’d hoped, the new PCBs are pretty cool. This whole time I’ve been learning electronics I’ve been building boards by hand; That is a foolish move. I took Sam’s advice and got them done up at APCircuits and the result was good. Here are some pics!

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