Darrelltech Homepage


When I started this page I had intended it to be an electronics related

page with a lot of links to help other Canadian hobbyists. I then came

across a page that already does pretty much what I had intended, and it

looks better than what I would have done. It's the top link at the

bottom of this page. So this page is now info about some of the

electronic related projects that I have done/built/fixed.

My server is not the quickest (and I'm no webmaster),

so I will keep my pages simple.


LCD Display

I had fun getting this LCD display module going. The documentation that came with it wasted

a lot of my time when it told me to use line 17 from the parallel port, when the test software it

came with assumed you were using line 16. The AVI file shows the results.

LCD Display demo video The video is about 6.3 MB in size.


APRS module

The 'project of the week' (Mid July 2007) has been to get APRS (Automatic Position Reporting System) installed

in my vehicle. I bought three kits off the internet and constructed them. I used the OpenTracker module, a Deluo GPS,

with an ICOM IC-25H radio.

More on the APRS page here.


Stepper Motor Driver

I had a week off before Christmas '07 and in between all the usual craziness I managed to find a little time to slap

together a stepper motor driver circuit. I don't want to call it a controller because it only goes in one direction, but it

shows the basics of stepper motor driving. Using the parallel port of a computer would also be an easy way to get the

motor moving, and in both directions, but I wanted to use a pulse generator. A simple 555 timer would work fine.

The only IC's I had that were handy for this ( that I didn't have to rip other stuff apart for ) were some TTL chips

I've been hauling around for years. I used a 7490 decade counter, a 7442 BCD to 10 line decoder and a 7404 inverter.

( If I would have had a CMOS 4017 or 4022 it would have been simpler. )

The rate of pulses fed to the 7490 control the motor spin rate. The 7404 is used because the FET's are N-channel and

the 7442 is inverted logic.

Picture of the breadboarded circuit here. I will get a schematic up some day.


Replace the battery in a Kenwood TS-50 radio

The Lithium memory backup cell in my TS-50 has been dead for a while so I looked up the replacement procedure on

the internet. Kenwood would like you to send it in to a service centre for replacement. I'm sure the procedure plus

shipping plus parts would add up to a lot more than a simple battery swap should cost.

So I did it my way, and took a few pictures if you'd like to see what I did. I used a cell holder from an old Pentium


My TS-50 battery swap page.


GPS Stuff

LCD Stuff

test area

A few Canadian links






Other links

Have a look at their 'Software Downloads' for some freebies - http://sss-mag.com/

A large list of schematics. Some 404 errors but good stuff too - http://www.satsleuth.com/schematics.htm


Digital Rights Management - follow the money...

Confined Space Safety - Glad this isn't what I do for a living (Power Point)

Amazing Fishing video - jumping right in to the boat

email: darrell@darrelltech.com

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Last update : 28 Dec 2008