What I've Been Doing for Over a Month

Once again, I've left it far too long since I last posted.  However, I hope I can summarise what I've done in the past month or so without making it insanely long.

Progress

So, once again, it's been about a week since I posted, and plenty has happened for me to comment on!  I've spent a fair amount of time mentally arguing with myself about various things, but I've actually done some work, too.

Catch-up: Software and PCB Production

I must apologise to any readers I may have, as well as myself, for letting the blog slip for two weeks.  I've mostly been working on software, but have been doing some PCB-related stuff too, and I didn't think there was much worthy of commenting on for now.  Anyway, here's what's been going on for the past two weeks...

Finalising the Hardware and Designing a PCB

I've been working towards the inevitable PCB production stage, making decisions and testing designs to allow a PCB to be designed sensibly.  Designing a PCB takes quite a lot of time to do properly, and learning to use the software effectively can take a little time.

A Lazy Friday

Some days feel a bit slow, and you don't get much work done.  The work you do get done, though, feels well worth it.  Today I tested out the serial interface, and produced a test pattern which should be useful for testing the floor sensors.

Motor Feedback and Hardware Design

Today I tested whether low-pass filtering of the current sense signals from the motors was of any use, and investigated some methods of getting motor speed feedback.  I also considered the use of the AVR's pins, and looked into obstacle detection and mapping hardware.

Considering Requirements

I started the day by researching more about FreeRTOS, specifically the differences between tasks and coroutines.  I then went on to explore whether FreeRTOS would be the best option for the robot, or whether I could make do with a simpler multi-tasking system.

Getting a Grip

Today began by investigating how to improve the wheels - this involved researching different tyre materials.  I also prototyped the serial level converter circuit, and looked into the use of FreeRTOS on the AVR.

Rewiring and Maths

Last week, I discovered some problems in the power system on the prototyping board, which caused the microcontroller to reset sporadically.  Today, I worked on this issue, and did some more work on navigation.

System Improvement

Today I did quite a bit of theory work and coding.  Most of this concerns the dead reckoning system.

Bits and Bobs

I've been concentrating on my initial project report for a while now, so I've not generated much new material.  I have been doing the odd bit of practical work, so I'll sum up several days all together here.

Getting Things Right

Yesterday I had some issues making the AVR work properly.  I couldn't get any output to appear on the LEDs I'd connected - I'd already found that the Data Direction Register (DDR) wasn't set correctly, and modified the code, but there was still some problem.

Making Things Work

Yesterday, I build a motor controller.  The primary aim today is to finish testing it with PWM, and to (hopefully) make the AVR do something useful.

Mechanical Considerations and Motor Controllers

Today's aim was to consider some of the physical effects that may be seen in attempting to track the robot's position.

Day Two of a Five-minute Job

Yesterday I began a task which led to several others - today I got back on track with what I started.

The Domino Effect

When taking on a task, it's generally accepted that doing it right is always better than doing it over later.  However, there are often limitations which mean that most tasks end up being done over later because you couldn't manage to do them right the first time.

A Man Needs to Build

It's true - I think just about every man needs to actually build something every so often.  For me, this need was fulfilled today, with the construction of my prototyping assembly.

Shhh! Be vewy vewy quiet - I'm hunting Power Suppwies!

Today has been a long day.  I've spent just about all of it looking into a solution for powering the Mini-ITX board from a battery.

Motor Control, Budgetting and SEPIC converters

I began today by thinking about motors and capacitors.  Currently, the robot has no motor decoupling capacitors.  Thinking about both EMI from commutation and the need for PWM to remain unfiltered, it's quite simple to figure out how big the capacitors are allowed to be.  I'm aware that most DC motors are typically used with '104' ceramic capacitors (100nF).

Hardware Homework, plus "Using the Right Tool for the Job" Lesson

This morning I actually looked at the gparted output from last week.  The 1.93GB used on the disk looks very promising if the system is to be transferred onto a 4GB compact flash card.

Pruning Xubuntu

Today involved work to the operating system on the PC board.

Some Proper Engineering

Today involved quite a bit of planning of how I'm going to continue developing the robot.

The Gathering of Information

Today began with performing some basic measurements to verify some information that appeared in a past report, as well as some additional information.

Interesting Installation

Yesterday, I failed to install Xubuntu on the Mini-ITX board when I found that the kernel was too recent and the CPU was no longer supported.

A Starting Point

Some Toys to Play With

I've had a meeting with my project supervisor, and acquired the robot and a box of extra parts that has already been acquired by past students.  Looking in the box, there are several useful components:

In The Beginning...

Introduction

This blog will serve as a day-to-day summary of my work on a two-wheeled robot as part of my MEng degree in Electronic Engineering.  Originally I intended to do video recordings, but used audio recordings instead when I couldn't find any simple software to do that.  Since then, I've discovered how long audio editing takes.

So now, having completed about two and a half weeks of the project, I'm reverting to text, and rewriting all the information I've produced so far.  Hopefully someone will find some of it useful.  Anyway, on with the show...