matqua.com blog

Starting my TurtleBot

matqua — Thu, 21 Jul 2011 07:24:46 +0000

So I have finally gotten some spare time and decided to start building my TurtleBot. I was going to spring for the laser cut parts and the nice metal supports but my budget currently could not justify them. So I decided to follow one of the I Heart Robotics blog posts about making them from hand.

I decided to cheat a little with the supports and used 16mm wooden dowel instead of the metal threaded rods. Check out the pictures below of the build.

Vintage Computing

matqua — Mon, 21 Dec 2009 08:49:59 +0000

I recently had the urge to muck around with some old computers. After exhausting my pile of crap at home I turned to the second largest pile of crap around, eBay! I started looking for an Apple Newton MessagePad and eventually found one. So excited I was.

However I kept searching, and found a HP 200LX Palmtop PC. I bidded and bidded and eventually after a second chance offer, I won it!

So now I have in my hands two iconic portable computers, both in full working order. I haven’t had a chance to have a good play around with them yet; but I will! Until then, please browse the pictures below and see all the oldies in their glory! (I couldn’t believe how small the HP was. I photographed it next to my Viliv S5 to give you a sense of just how small and well planned it was)

Arduino LCD

matqua — Wed, 10 Jun 2009 10:24:45 +0000

So today I finally got a dot matrix LCD module from Dick Smiths (Z4172) and proceeded to wire it to the Arduino. Ended up working out pretty good although the USB was struggling to run the Arduino + Ethernet Shield + LCD (the LCD contrast was dull even with the 10k pot wound right up). No biggie, I just pulled the Ethernet Shield off and went directly to the Arduino. It will probably be used almost exclusively on one computer so I think I will just control it via the USB serial port.

One thing I could not work out was why the screen would not work if I was using digital pin 1 for one of the connections. I ended up using from 2 to 8 which still allows me to use it with the Ethernet Shield should I want a networked little display! My initialisation line was LiquidCrystal lcd(2, 3, 4, 5, 6, 7, 8);

Check out some pictures of it below (extra points if you can work out where the quote on the screen is from without using Google!):

Arduino Ethernet Shield

matqua — Mon, 08 Jun 2009 07:48:39 +0000

I’m excited. My Arduino Ethernet Shield arrived from Little Bird Electronics last week. It is cool having the Arduino pingable on my network!

I have quickly hacked the SimpleMessageSystem to respond to commands over TCP/IP rather than the serial port and it seems to work ok. I have to code some more error checking and handing of the write commands but it shouldn’t be too difficult. I’ll have to see how I go about sending in my changes to Arduino’s site. Maybe I will just post a link to the networked version on my site. It will make interfacing with the Arduino from web pages (such as PHP like I am going to do!) far easier than through the serial port.

Check out the pictures below of the board and the software. It is in a very alpha stage but hopefully I should have something worth downloading in the future (probaby distant future).

Laptop Photo Frame

matqua — Sat, 23 May 2009 09:46:45 +0000

So you have this really old laptop that has less power than a new Eee PC. What to do, what to do? I guess do what everyone else is doing these days and turn it into a photo frame!

The victim was an old Acer TravelMate 240. It ended up being quite an easy mod. The hinges were symmetrical and the inverter and video cables for the screen were more than long enough for some re-routing. The hard drive is full of errors so I am booting it off a USB key. The problem with that was the BIOS does not support booting from USB. I dropped on a custom boot loader on the hard drive that then boots off the USB drive.

Currently I am running Puppy Linux off a 1GB drive. It runs very well. Now all I need is to install an image viewer and have it mount a photos share off the house server and it will be complete. Check it out in the photos below.

Arduino Temperature Sensor/Logger

matqua — Sun, 26 Apr 2009 10:08:12 +0000

I’ve always wanted a temperature logger for my computer. After some reading I found a pretty easy solution for added temperature sensing to an Arduino project. After building the circuit I programmed a quick and dirty serial data logger application in VB2008.

I added a 10k pot to try calibrating the sensor but always had a discrepancy between it and my desk thermometer. I’m going to look into geting another thermometer to see which one is lying. You can see the circuit, software and a sample plot of the temperatures overnight in my computer room below.

Heat testing the temperature sensor with the mini. Damn little thing wouldn't blow enough heat, even with F@H running!

A quick and dirty serial port data logging program.

The temperature in the computer room from bedtime to wake-up. The next version of code will add some averaging of the samples to improve accuracy.

Broken H-Bridge Drive

matqua — Sun, 26 Apr 2009 09:44:36 +0000

My attempt at a H-Bridge drive. It didn’t work. Probably because I could not get all the right components and ended up substituting.

A non-functional h-bridge drive that was destined for my RC car

The Business

matqua — Sun, 05 Apr 2009 04:20:57 +0000

This is by far the best thing ever. It is "The Business".

No posts for so long

matqua — Sun, 05 Apr 2009 04:16:20 +0000

Hi All,

Sorry for the people who actually follow this blog; I have been crazy busy with work and family stuff. In my spare time lately (when I have been near home!) I have been hitting the photography a far bit. You can check out some good shots on my flickr page (http://www.flickr.com/photos/matqua/).

Don’t panic though, I am still tinkering around with some cool, geeky stuff. Right now I am working on an Arduino-based data logging system with an Eee PC. I’m wanting to sample the output of a solar panel and log the power data over a few months. Hopefully that will be operational (at least the GPS data logging component) in the next few days.

Anything interesting or anything in general? Feel free to drop me a line.

Matthew

Arduino Action

matqua — Sat, 20 Dec 2008 10:22:26 +0000

Hi there. Today I finally got some time to sit down with my Arduino Duemilanove (and motor control shield) and have a good play. Firstly I hooked up the Duemilanove board and played with a few examples (mostly just flashing LED 13 a few different ways. I did want it to flash the beat to “Everybody Dance Now” but didn’t want to spend that much time!) then got onto the task of building the motor shield.

Thankfully the motor shield works perfectly. I was able to control the steering of my robo-car with a servo connected and able to drive the car forwards and backwards using a standard DC motor connected to one of the motor controller inputs.

After that, I dove into writing a small test program or “sketch” in Arduino language to read the ultrasonic rangefinder I am placing on the front of the car. After an hour of tweaking I seemed to have succeeded. The sketch I wrote reads the analog pin, averages the last three readings to keep the distance a little more stable, then converts the voltage reading into a cm value. The Arduino then pipes the results out the USB serial port. The setup and output can be seen below. If anyone is interested in the code, drop me a line.

Next step, interfacing the motor shield with RoboRealm! Should be easy.