This page is dedicated to the further enhancements that I have done to DominoBotNXT. For more info on the original DominoBotNXT, have a look here. 
One of the drawbacks of the original was that due to the 3 motor limit, it had to backup to properly place dominos. This was because the domino-placing component was tied directly to the drive wheels. So, as it drove forward, a domino would make its way to being placed in the holder mechanism. Doing this caused the robot to move forward approx. 4 inches. Since this is too far for domino’s to actually cause any chain reaction, the robot had to move each newly placed domino back to be within 1″ of the last placed one.
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December 2006:
Sometimes my robot building ideas are spurred by nothing more than wanting to make use of one or more cool items that I get from time-to-time. In this case it’s two – tread tracks that can be had if you own the Technic Snowmobile (8272) and a TechnoStuff Tilt/Accel Sensor. 
I was fortunate to have received a huge bag (a few hundred segments along with wheels) of the new tread tracks a while back and begun playing with them to see how they compare to their smaller black Technic counterparts. In a nutshell, I like these ones better as they are larger (more suited to the size of robots and Technic creations I build) and stronger – they dont come apart as easy. They also have pin holes in them to boot, so the sky is the limit for making large tracked vehicles.
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April 2007:
What better way to test a colour sensor then to create a brick sorting robot! After getting my hands on a HiTechnic colour sensor, I first took a stab at creating a robot that could navigate a room and detect colour. There was only one problem, it could not really do what I was hoping for. I was nieve in thinking that I could build this robot and it could detect colours from a distance. After reading the fine print on the provided documentation, I quickly realized that the colour sensor is only capable of reading colours at very close range (~ 1 cm). My bad. Of course, you could still build a robot that uses the ultrasonic or other sensor to get it close to objects, then read the colour… but that’s for another time.
BrickSorter uses this colour sensor to detect the colour of bricks and sort them into a variety of cups. The program is quite simple, gravity and studless beams allow for each brick to slide down the track on its own. when a brick is next, the colour sensor takes a reading (more on this later), the sort motor turns the sort rails to the correct cup, the sort rail motor changes its angle depending if the cup is close or far and finally the kicker motor kicks the brick in motion.
After a lot of fooling around with the cup placement (which seemed to be the hardest part of this project!), I managed to get the sorting pretty much bang on. Of course, the video shows some goofs, but that is mostly due to the small sized cups (its all I had!)… Anyway, I found the sensor to be accurate most of the time, but ambient light still influenced the readings at times and caused for the odd random missorting of a brick. I had to shoot the video about 10 times to get cup placement and sorting goofs worked out.
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April 2007:
Your first question is probably “what does UNV stand for?”. Well, its nothing special – I simply could not come up with a name for it, so what better way to tag it then simply unnamed vehicle. After receiving a bunch of the new tread links, I wanted to create something grand with them. Scouting the web, I came across these multi-purpose robots (see below) that can be outfitted for police / bomb squad use, or for scientific work. Thought they looked pretty cool, so they were the inspiration. UNV was sitting around for months before I finally got around to taking pictures and a video of it. Read on for details…
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Jan 2008:
WifiCamBot was one of my adventures in building a robot that could be remotely driven around while transmitting video via a live feed through an IP-based network camera wirelessly.
The idea came from my wanting to do something simple. Survey underneath my deck to see what sort of critters etc were making a home there. The deck was high enough for a rover-like vehicle to fit and drive around. I did not want to have wires tethered to the system, so I used a Panasonic BL-C30 WiFi camera with a built-in webservr to transmit live video via the web.
In this case, I have a webserver where I created a subdomain specifically for the camera to broadcast its info to. Loaded the Java components to receive the streaming video and render it on the site. The site also allows for remote control of the camera via WiFi. So, the entire robot, power and electronics are all onboard. There were a few challenges with this approach. 1) Power – The Wifi camera required 12 volts dedicated power. I did this by wiring 2 battery packs together in series (required a custom modified motor wire). This also added a fair bit of weight to the robot. In total there are 2 battery packs for the WifiCam and 1 for the PowerFunctions motors. That is 18 AA batteries. No worries though – the PF motors still have lots of torque.
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Big Wheel (BW) was an experiment at building a robot that uses the HailFire Driod (StarWars) large wheels. 
It’s job is simple; build an autonomous robot that can navigate any area while avoiding obstacles by not hitting them in the first place. To do this, BW uses a DIRPD sensor to “see” left, right and center. This allows BW avoide obstacles from 3 views before actually hitting them.
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PicoCam was built as a proof of concept. Its purpose was simple, navigate an area using typical avoidance routines while capturing live wireless video/audio and transmitting it to a receiver.
The was never really completed because I had other ideas brewing… The pictures shown here are of the final version, with working navigation, but I did not bother going the last step to get the live video to display (even though it will work).
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One of my early projects was to build a fire extinguishing robot. I did this using the parts I had at the time. It was based on a walker platform and used a pneumatic circut to “blow” the fire out when detected.
It worked reasonably well with the provided light sensor. Recently, I discovered the PIR (Passive Infrared Sensor) from TechnoStuff. This sensor was built to detect infrared heat and seemed to be a good fit for my next project. I mounted it to my new FireBot in tandem with a standard light sensor. Together, they would do the job of detecting a flame.
A candle was used as the “fire” in this project. The PIR sensor was mounted alongside with the standard Lego Light Sensor. For more details on this sensor, visit my Reviews section.
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You would think I have a template for “room-navigating” robots… TrackerBot evolved from the recent PicoCam robot I created. After I had finished PicoCam, I decided I wanted to try something with tracks. TrackerBot and PicoCam share similar intelligence, with TrackerB
ot having some slight improvements. The general idea is that it will navigate a room using a variety of sensory input for obstacle avoidance. There are 3 Cybermaster touch sensors, 1 DIRP light sensor and 1 line following standard Lego light sensor.
The DIRP light sensor (seen here at the top), does most of the work. It is set-up as a light sensor and detects left, center and right objects. It does a pretty good job of making sure TrackerBot does not hit things. The Cybermaster touch sensors are used to detect objects that are low, at the back or out of the line of sight of the DIRPD sensor. They are wired such that all 3 sensors can be placed on one port (more on this after).
TrackerBot is also equipped with a pinhole wireless colour camera. It can broadcast live colour video with sound to the receiver and show its progress on TV. It is more of a proof of concept than any real function. Read on for more details…
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Sept. 06:
Pete @ Techno-Stuff has just sent me another new sensor from Techno-Stuff. This time it’s a Accelleration / Tilt sensor. Instead of going into great detail on how it works, I will quote from his site:
“ The Accel Sensor lets your robot measure it’s acceleration. The sensor can also be used to measure tilt. This is a two channel device that lets you measure acceleration or tilt along two perpendicular axis. Accelerat
ion is a change in speed. When you push the gas pedal of a car, and the car speeds up, this is acceleration. The Dual Acceleration/Tilt Sensor (Accel) measures acceleration by it’s effect on a small mass. The sensing mass is also affected by gravity. Because of this, the sensor can be used to measure gravity. Gravity is constant, and points straight down. Since the Accel sensor can measure gravity, you can use it as a tilt sensor. The sensor is most sensitive to tilt when it is mounted so the sensing channels are perpendicular to gravity. (the electrical connector is horizontal) When mounted this way, the light sensor value will be 50, indicating zero acceleration. The value will increase or decrease depending on the direction of tilt. “
So, to put the sensor to the test, I thought what better way to do this than to use my NXT kit.
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