OddBot's blog

There have been several previous blogs and forums on LMR concerning different methods of robot navigation and room recognition. I have decided to make some IR beacons for experimenting with.

My theory is that if each room has at least 3 beacons spaced around it then the robot can not only triangulate it's position within the room but also determine what angle it is facing. Each beacon sends out a different identification code. This allows the robot to know which room it is in.

This was the first Makers Faire where I got to go with ChopSticks!

It was the first Makers Faire ever to be held in China so as you might expect it was not the huge spectacle that the American faires are. Eric Pan, who is the CEO of Seed Studios and currently sponsering LMR did a great job in organising this event.

Friday 27th January, 2012
This blog is a an ongoing list of my thoughts, as I attempts to create a library for the Micro Magician. It is boring and should not be read by anyone :p

As some of you may already know, I am designing a new Arduino compatible controller for small robots. One problem with small robots is limited space. This makes sheilds, motor controllers and wires difficult to fit. For this reason I tried to incorporate a few useful devices onto a controller while keeping the cost low.

Well 2012 is off to a great start with a brand new Arduino compatible controller, A car controlled by your phone and a robot arm with teaching pendant from DAGU.

The Micro Magician is designed for small robots running on low voltage batteries. The controller works on voltages from 3.6V to 9V.The heart of the controller is an ATmega168 running on 3.3V with an 8MHz clock. Check out the great new features!

Chopsticks arrived back at DAGU today in good condition. Andrew did a great job and even sent me a cool "T" shirt! LMR logo is on the back.

Well done Andrew!

It seems in China you must travel to the brides birth city (or a city nearby her birthplace where they keep the documents) to be officially married. 3pm Sunday afternoon we were on our way!

We had to travel 5 hours by bus from ZhongShan to XingNing to get my step sons passport. The bus had beds for the long trip which was great for small Chinese and children. Not so good for a 135Kg Aussie!

G'day everyone,

I have been designing products for DAGU for over 2 years now and have always tried to provide product support here on LMR. One problem I have had is that sometimes the manuals are too big to upload.

If you have any problems with these kits then you should ask questions in the component section. I answer questions there so that others with similar problems can look for answers.

The components on LMR are here:

WARNING! this blog is just my thoughts on the subject and may be prone to rambling, monologs and contradictions.

I want to develop a universal navigation system for my robots. By universal I mean that the same code should work on almost any robot with only minor modification to allow for I/O pins used and number / type of sensors. This code is being written for the Arduino but I will document the code well enough that it can be easily adapted for other processors.

Theory Stage:

21-5-2010

A few things have happened this last month. I meet Xiao Yue (Little Moon) about a month before I went to Australia. She can't speak much English and my Chinese is still very bad but she seems to like me anyway.

This was taken on her birthday. There was a bit of a food fight with the cake so we ended up with cream on our faces.

31-5-2009

The last 6 months of my life have been full of ups and downs. I have been on workcover for the last 6 months for an injury I sustained at work. This gave me the time to discover LMR and make new friends (and robots). Thanks to LMR, Jack from DAGU discovered me and is now producing not only my robots but will soon produce other robots from other builders at LMR.

One of the most important parts of a robot is it's sensors. If it cannot sense it's surroundings then it cannot respond. Unfortunately good sensors are usually expensive. For this reason I am always experimenting with cheaper home made alternatives such as my light up antenna, conductive foam touch sensor, IR obstacle detector and my not so successful laser range finder.

I have seen a few people asking questions about controlling Mr. basics motors. One problem is that they draw more current than an L293D can handle. A L298N will do the job but you will want at leat 6V. Below is a schematic of the simplest way I know of to control your motors. Using a 5V relay you can run from 3.6V to 6V. I suggest a 9V relay if you want to use 7.2V.

Building an arm for your robot can be the hardest part of robot design. There can be many different designs besides a humanoid design. For example you might have a CNC style XYZ axis or even a tentacle design where multiple joints are surrounded by cables. For BoozeBot I've decided to go for a humanoid design because I would like him to be able to pick things up like a person would. Reguardless of your design the first problem you are likely to face is strength vs weight.

** Update **

I delivered the gun to KJ precision engineering for testing. It has been named "Soldestroyer" by my former boss.

This was my camera tripod used for videoing my robots at ground level.

After videoing Turbo Trike I left it in the car by mistake. I forgot all about it. After the car being in the hot sun for nearly a week, I found my tripod like this............

One thing most robots need is a power supply that can put out a reasonable amount of current for servos and other small motors as well as run a processor and sensors. Probably the best setup is 5x 1.2V NiMh cells to provide 6V for motors and servos with a low dropout regulator providing 5V for the processor and sensors. Unfortunately this isn't always practical. Sometimes you have motors that need higher voltages or maybe the only battery you have lying around is a 7.2V battery from a RC model.

There have been a lot of questions lately about transistors, NPN vs PNP, Bipolar or BJT vs FET and their use in "H" bridges. I had considered doing a tip/walkthrough on the subject but typing "transistor" into google gave lots of great results. Same happened when I typed in "H bridge design". I realised I would be wasting my time writing a tip/walkthrough on either subject as there is better more detailed explainations already available. So for those who are afraid to google I present these links.

Every now and then I want to test a circuit or a new sensor or even some new idea for code but I don't have a starter kit or anything. While shopping for some robot parts I had an idea for a simple base that could be my equivalent of a starter kit, a power supply and a small robotic platform. This is what I came up with in 5 easy steps.

This is my second attempt at a homemade laser range finder now with video. I nearly gave up after hearing about the Sharp IR sensors but I think this has potential as it focuses on an area the size of a laser pointer spot. The other sensors work on a much larger area. After a lot of frustration I've finally got all the circuitry working properly and hope to have a video posted as soon as I work out one last difficulty. Click on the photo for a full sized image. This is a work in progress, not a finished product.

My laser range finder got a lot of interest so I thought I'd try to explain it in more detail.

It's not finished yet as it still needs to be mounted on it's stepper motor with a home position switch.

The sensor side has been tested on an oscilliscope. When I moved my hand in front of it, the pulse width varied to match.  Below is a diagram showing how the sensor works.