Stepper Motor Control Using PIC16F84A & ULN2003 – v1.5 – TEC 585


This is a very simple circuit and  its code (PIC Assembly)

Here are EAGLE3D images of the board (TOP & Bottom)


Notice how good looking this board is. Compare it with the ugliness of my  first (embarrassing) board.

Due to the gear used in the university lab, I had to increase the width of the tracks to 50 mils, and make big fat Pads. I had to Edit the libraries of every component to make big Pads, as when I used the standard ones and etched the board, I totally ate away the pads copper when I drilled. Actually, fine tracks aren’t that much of a problem, but PADS are.

Note to self: Don’t be afraid to super-size.

The one without varnish is the second one, but then I did one more iteration (I was wrong in the tactile switch) and got a last one which was varnished.

The tactile/push-buttons that were available didn’t have their library in Eagle, so I had to create them (it’s .3 inches long and .2 inches wide). I had some problems doing that, but I was helped on the ETO forum. (Thanks Inquisitive).

You’ll notice on the TOP view that there are some missing parts.

You can download the whole project (.rar archive containing Eagle schematics & custom libraries + board files + .asm source code): HERE

The two ports are pulled high via a 10K resistor (9.8K on the actual board), and each sequence is launched as soon as we pull the pin down (held down).

PORTB is configured as output, RB0 through RB3 go into a ULN2003 7 Darlington Array, outputs of the ULN go to the stepper motor.

Schmitt Trigger With uA741 Op Amp (College Paper in both French and English)

This is the first lab assignment report. It’s kind of simple and its purpose is to dust off neurons and get in the vibe after a three months plus break. TEC 588 at USTHB.

It’s a paper about a Schmitt Trigger circuit using an operational amplifier (uA 741).

The use of software here was just for the schematic, since we already drew the signals witnessed on a nice old cool analog scope (Gotta love the sounds these buttons make)

Here are the links for viewable and downloadable PDFs:

For the french version:

For the english version:

PWM Using NE 555 (PCB with EAGLE. College Paper in French TEC 585)

The PIC Programmer project is out the window (for now), as I was busy with many things (college related, mainly).

The main reason I wanted to do a PIC programmer was to make som PCBs, and to get to program a PIC. The teacher told me that there is everything I need (including parts, programmers and chemicals (reactives) to do that..).

So I’m taking care of college stuff, doing something I wanted to do, for free.

For those of you who don’t know me, people around the world should celebrate the fact I attend classes this year, with kumbayas and all the stuff.

The TEC 585 teacher (A class with boards, circuits, practical stuff as a main focus.. PIC programming, etc..) gave us a circuit which got no indication (parts values, or names, etc…).

So I had to “figure it out” so to speak..

The circuit is to be transformed into a PCB in the Lab, as a “learning by doing” thing, a month or so from now, with the teacher showing us all the stuff, a month or so from now (Things move really slow)

Meanwhile, I did the layout on EAGLE. I’m not very good at it, but it’s respectable. I issued a paper which can be found here:

It shows the different steps of the board, ripping routes, and creating ground planes, copper pours, etc…

It’s in french, though, as we don’t study in english at the university.

TP1 TEC 585   Ingénieur Instrumentation (électronique)