Electronics Shop

This is a collection of some of my electronic projects that I have been working on. I also keep this page as a 'to do list'.

For most of my electronic projects I use open source software gEDA for design.

http://www.geda-project.org/

DVB T dongle

This is a cheep RF USB dongle. I just streams raw I & Q data.

3D Printing.

I just got a Solidoodle 3rd generation 3D printer. It is a lot of fun. It is like having infinite Legos. I have been making some project boxes for my development boards that I like to use. Here is a picture of half of my Raspberry PI case. It turned out pretty good even though I had not calibrated the printing for the Slic3r program.

Some things that I have found helpful.

    • If you are not already comfortable with the metric system, learn to love it.
    • Level the build platform.
    • Calibrate your print software and hardware.
    • You will need a few other tools. (see my list below).
    • I print with a brim around my parts. I seems to help keep them attached to the build platform and reduces warp.

Tools that you will want / need.

    • A pair of digital callipers.
    • razor knife.
    • A putty knife with a very thin flexible blade.
    • IR thermometer (not necessary, but nice to have.)
    • Super glue. It is good for fixing parts that you break or weak places in parts.

Slic3r Filament settings

Nozzle diameter: 0.35mm

Filiment diameter: 1.71mm

Extrusion multiplier: 0.6067

Nozzle temp: 193C

Bed temp: 105C

Modifications to my Solidoodle.

I have added plexaglass sides that attach with magnets to the sides. I did this to keep the temperature stable and I did not want my 2 year old to get burnt.

I have also changed to printing on glass. I found it to be flatter than the aluminium build platform. I have also gotten better adhesion between the prints and the glass. I did chemically etch the glass so it was easier to see the surface and to get better adhesion.

3D modeling for gEDA

I have created a Perl script to combine a library of OpenSCAD part models, Schematic, and PCB files to create a 3D model of the whole PCB.

Electronic finish line judge

This is an Arduino project to judge who wins a pine wood derby car race.

It is a simple design with an IR LED and receiver for each lane. The Arduino Uno just poles the receiver to see when there is a state change. The program then turns on an LED above the winning lane.

RGB LED lighting

Using an Arduino Mega and IOIO open source development boards. It is controlled by an Android app using Bluetooth.

SMD part holder

I use this to hold some SMD parts down on PCBs while I am soldering the parts. It is built out of mostly scrap that was around. The PCB that is attached to it has some white LEDs mounted on it to provide a little extra light where I was working.

Amateur Radio Fox (hidden transmitter)

This transmitter was used to practice finding hidden transmitter. It is a very simple design, it just generates a week noisy carrier. It did this by turning on/off a TTL oscillator at 146.55 MHz at an audio rate ~1kHz. This transmitter out put was detectable using AM or FM demodulation and had harmonic content up to about 1GHz. It was good for learning about direction finding techniques.

PIC Robot header board

This was part of a design project while I was in school (This is the spare, why build one when you can build two for twice the price.). It has two LM629 servo control IC (1 on the front and one on the back) and two MC33886DH H-bridge IC's. This PCB mated with a PIC18Fxx20 development board. This PCB was cut out with an LPKF PCB router that the school had.

I also have a protype of the IR sensing board that I will add also. It is an array of 14 IR LEDs and receivers. I then used some SMD schmitt trigger inverters to buffer and convert to a logic level signal.

This is a picture of the complete robot that our team put together. It was for the 2005 IEEE SoutheastCon Hardware Competition "PacMan". The overall robot size is 6in x 6in x 12in.

Hot Air Soldering Iron

I made a prototype of this with a heating element and a mini 12VDC fan. It seems to work ok. I will be improving it to use an aquarium air pump and a small air regulator. I also need to add better temperature controls.

Solar Suitcase

This project is a 5W solar panel, 150W charge controller and large electrolytic capacitors packaged in an old suitcase.

Near field probes

I built the 1cm and 3cm H-field probes. These are electrostatically shielded so they will only pick up magnetic fields. The base of the probes are 3/8" copper pipe. The loop of the probe is made of 1/8" copper pipe. Inside the loop of the probe is a teflon wire.

I plan to build a 6cm H-field and also an E-field probe. I have not decided if I will build a pre-amp for the set or not.

Making toner transfer paper

I have started making my own paper for transferring laser printer toner to bare PCB for etching. The results have been ok and I have been able to make working PCBs from them. Plus the materials for making the paper is pretty cheap.

Stepper motor controller (In progress)

I am refining output stage for a stepper motor controller. My goal was to create a simple and reliable design.

I have completed the first complete prototype design.

The design uses a PIC16F636 for the logic and inputs. Then there is a discrete Mosfet driver outputs for each of the 4 phases of a unipolar stepper motor. The stepper motor supply voltage is separate from the rest of the circuit. This allows the controller to be configured for motors with different voltage and current ratings.

This stepper motor controller will be used with my 3-axis CNC mill

https://sites.google.com/site/matthewsager/home/projects/machineshop

EDM (Electrical Discharge Machining) controller

Electrical discharge machining is using an electric arc to erode a metal work piece. This is done in a dielectric fluid. The fluid keeps the work cool and cleans the gap between the electrodes of the burnt metal.

Capacitive welding

1-wire weather station

This is a project to use some of the Maxim sensors for internal and external environment measurements.

Broadcast band FM transmitter

This is a low power transmitter that operates on the broadcast band. The use is to play audio through a regular radio. The project uses the MAX2606 chip from Maxim. It also has two digital pots to control the volume and the transmit frequency. The board uses a 3.3V regulator for the power supply for all the chips.

Gerber to Gcode (link to soruceforge.net project page)

This is an experiment with using subdivision as a method to isolate trace edges on a PCB for milling. I need to work on the next release and separate the linux and windows release files. This will make it clearer for any one who wants to build the program.

The Source forge wiki has the best information about how the program works.

Camera time-lapse controller

I made a version of Achim Sack's Interval timer. The only difference is I made my PCBs a little larger so I could put test points for programing the PIC.

http://cms.diodenring.de/electronic/microcontroller/82-intervalltimerv2

Electronics bench vise

I put together a better bench vise using a 12in tile and some PanVise parts I got at a Hamfest for cheap. The jaws and the PanVise base were not intended to work together, but I used some bronze bushings and a set screw to adapt them.

HD TV antenna

I built me a TV antenna for over the air HD TV stations. It is a single bay Gray-Hoverman Antenna. The specifications and dimensions for this antenna can be found at the link listed below.

http://www.digitalhome.ca/ota/superantenna/index.htm

It is a simple to build and is working very well for me. (This picture of the antenna is in the attic.)