Let's Make Robots!

The Pulse - 2008w50

LMR on the Brain
Sensing the living LMR community since 2008w43.

Xmas Lights Tester

So, you accidentally stick a regular clear bulb in your Christmas lights (fairy lights [US] ?) instead of a fuse bulb. Next time there's a bit of a surge, there's no discernable weak point in your circuit and it takes out more than one bulb. Where do you start debugging that?

Sure, you could sit with a multimeter and probe all the bulbs to find the duff ones. Have you ever tried to attach multimeter probes to a fairy light bulb?!?! It's a nightmare. Specially when you only have 8 fingers and two thumbs.

H-bridge using L298

Now that I have the rotary encoders working properly, it's time to think about the motor control circuit.  I have an Atmel AVR ATmega32 with three PWM outputs, of which I'll use two for motor control.  I'm planning a differential drive robot, that is, one with two drive motors, one for the left side and one for the right side.  I'll need forward and reverse directional control of both motors, as well as speed control via PWM. I have a couple of L298 H-bridge chips, so they'll do nicely.


It flies, it flies!!

I posted some time ago that some friends and I were building a Semi-Autonomous Quad-rotor helicopter for our Masters' Project at uni. Well, we've been working hard, and have finally built the actual helicopter (using a kit found at http://www.mikrokopter.de ). After most people had left uni last night, we found a large open space to do some simple test flights. I would say that the flights were a partial success, in that we now have to calibrate all the controls and work out exactly what each control is doing (I crashed the helicopter on its second flight!)

The Pulse - 2008w49

LMR on the Brain
Sensing the living LMR community since 2008w43.

Making a quarature encoder

This is a photo of the encoder disk that I'm working on for the Hitari Tumbler robot chassis modification.


4WD robot chassis

I'm looking at a Hitari Tumbler radio-controlled car chassis.  It has four wheel drive, with front and rear wheels on each side geared together, and to the motor.  There are, of course, two motors, for left and right side drives.  It's old, and missing the bodywork, battery and radio transmitter -- but we won't be needing any radio!

Chris's Day Job

Hey folks,

I thought I would give you a peek a what I do for a living. I just finished this built-in for a HAM radio guy. The bead-board on the back wall is poplar and all hand milled while the desk and shelves are 6/4 and 8/4 African Mahogany. The finish is a hand-rubbed tung oil.


SED or Smoke Emitting Diode

This is an attempt to record the very edge to which an LED can be driven. A failed attempt.


I tried to post this as a component page, but it would not take embedded video...

The LEDs I tried are rated at 30 mA maximum. The forward voltage is between 1.9 and 2.1 V. I used a power source of 8.1 V  and a variable resistor in series that could range from 5000 to 0 Ohm.

Aquiring loot

Today I finally got a proper MCU and programmer, the missus bought me a late birthday present, a PicKit2!


 I have it hooked up, and running the initial demo, but have yet to figure out... well, everything :)

It all seems pretty straight forward, but I haven't dug myself into it quite just yet...



Taking a small break to give thanks.

Things are being put on hold for family and friends this week, being Turkey day for us in the states, and I've been thinking about what I'm thankful for.

I know i haven't been around here long, but I am GREATLY thankful for you guys here. For Frits making the yellow drum machine and encouraging other's to try it, which first got me interested, Rik for the distractions and adding more crazyness to my final project, and everyone else out there that gave me encouragement and wild ideas.

sweet! (home area network)

Check out today's score!


A colleague gave me this linksys WRT54. The dreamed version with the lotta-RAM and lotta-flash. For free.

The Pulse - 2008w47


Sensing the living LMR community since 2008w43.


Im off to buy An RC car to create a robot first basic things (pre defined movement) then logic


Im will use an arduino Duemilanove  

Pololu components integrated

A few weeks ago, Frits posted a blog entry explaining that we were working with Pololu to integrate their product catalog into our Components section. It took longer than expected to wrestle Drupal into submission, but at last the integration is complete, and as you may have noticed on the front page, all of Pololu's 300+ products are now listed as Components. Feel free to browse around -- the cool thing about it is that all of those components remain editable by every LetsMakeRobots user, so you can post comments, tips, opinions, etc about any component you want.

Gear pager motor not enough power

Okay I am trying to hook up the gear pager motor to test it so I write the code as below:


high portc 3

wait 1

low portc 3

wait 1

goto main

I used the lead to test it and it seem to work the lead turn on and off every second but when I try with the gear pager motor its does not have enough power to move the motor. well the motor move but very slow so its not able to make a sound when it hit something.gear.jpg


heat sensors


After reading the new sensor wiki, I'm reminded of a robot I've been planning, that relies on temperture measurments. Basically I want the robot to act like a photovore, only looking for heat instead of light. Is there a way to sense heat at a distance (6-10 feet)? 

Happiness is...

A fresh catalog shipped from Digi-Key.


Pardon me if I don't post around here for a while. I'll be busy with the precious. 

And one more lesson for you children...

Save your final paper in many places, that way you don't accidentially delete something and have to rewrite the ENTIRE paper in 2 hours using a finger with a hole in it.

*falls over dead* 


Documentation - redundancy redundancy redundancy!