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Visar inlägg från 2013

Line follower robot prototype

Before Stockholm Robot Championship 2013 I built a prototype for a line follower robot. The goal was to build something quickly that would be easy to modify, get it to go around the track and then learn as much as possible for a perhaps next version to come. It's the first robot I've built, apart from basic one we built in a project course.  I tried an Olimexino ARM development board for this project. It's basically an Arduino clone but it's physically smaller and lighter than the Arduino Due board, and cheaper, at least on eBay.
I had slight problems with the drivers on this board. Here are some info about Olimexino drivers that at least helped me:

 However, when considering the "bang for the buck" Olimexino is still an attractive choice when compared to Arduino I think. 

 I have some stuff laying around in the drawer that I would like to try out on this robot if I choose to continue on it. For instance I would like to…

Ignition system: Progress!

I've gotten it to start! The electronic systems had probably been doing their parts correctly for a long time. Problems were in the mechanics department of the engine, where valve clearance was missing. 
That resulted in that the valves never closed correctly and compression was lost. After fixing that, the engine once again gave signs of life just after a few kicks.

 First it didn't want to rev up, so I thought that the carburetor was giving me troubles as it usually does. I tried to move the ignition trig point from around 17° to 30° before TDC (the same as opening the breaker-points on the original system).
The first of the aforementioned points is marked from factory with an “F”, 17° before TDC, and this is where the pre-ignition is supposed to begin when the motor is standing still. Point number two is the one 30° before TDC,  also factory marked, but without text. Maybe that one marks when the spark is supposed to come when the engine is spinning fast? 
When giving spark at…


To develop mechatronic and electronic system you need tools and materials, knowledge and loads of persistence.   While the development and design process can be quite time consuming it's probably the part when getting it to work in practice that steals most of the time and there I am right now. 
A new completely analog ignition circuit for debugging purposes

The bike started a few times during earlier attempts with my ignition system, so the bike hardware seem to do its part. However it didn’t run for more than a few seconds each time it started on that occasion.
During that time I timed the spark in relation to the zero crossings from the AC generator, so no external sensor was needed. However, phase shift from the generator was occurring especially during the critical start RPM’s which moved the zero crossing nonlinearly. That made it hard to actually know the position of the engine.
 When I got it to start I was just having luck with the values I choose on an ignition curve in t…

Creation of an ignition system: Introduction

Since I was a kid there has been a small Honda XR75 -1978 motorcycle around that never really have worked for more than around four hours straight.  One frequent reason of failure has been the mechanical ignition system that has a mechanical ignition advance mechanism. Though kind of neat that this somewhat complicated feature can be realized mechanically, this system hasn’t worked well in practice. 
The mission is to construct an electronic ignition system and then take a ride on a summery day.

Current progress
This project has been going on for a while, so I  skip ahead a little bit and publish material from the current progress. If or hopefully when I get it to work as desired I will probably post a full description of the whole project.

Recently I've mounted a hallswitch underneath the flywheel who's task will be to trigger another circuit I've designed. That circuit in its turn will do more or less the same thing as the mechanical contact-breakers on the original syste…

The heating system

One of my former projects was the design and practical realization of an automated wood fired heating system. Two key characteristics of the project were the reuse of junkyard bargains and realization of electronic system starting from component level. Budget was kept low.

The system is now warming a house situated on a farm on the Swedish countryside.
 I for sure have never done a project spanning so many different categories of work. In the end I had done manual metal work and welding, plumbing, electrical installation, creation of control- and calculation algorithms, circuit design and programming to name some.
A box on the upper floor of the house with an Atmega328 microprocessor controls the whole heating  system.  
Here is a video summary of the project:

Systems furnace is a Braland 21 from
The control system that is now up and running can among other things monitor 16 different temperatures, control all the systems pumps and do different kind of logging.

Check t…