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.