Let's Make Robots!

A peek inside an electric bike motor

I have started on a new project and decided to use electric bike motors. I though some of you would be interested to know what's inside. These motors have good power and torque so no gearbox is required and with all those small windings inside they allow fairly precise control of speed and direction without any mechanical play.

As I want these motors for a robotic project I did not buy the speed controller normally used as it would not suit my needs. Electric bike controllers do not normally have reverse. Now I am building my own.

Could you use the 256K of memory on the newest Arduino?

Recently the Arduino IDE has jumped from 0018 to 0019 and today I found version 0020 available with support for the ATmega2560!

To me this is great timing as DAGU is developing a new robot controller (Arduino compatible) designed specifically for humanoid and hexapod style robots that require a lot of servos.

The real question is, does anyone think they could use 256K of flash program memory? I thought 128K was heaps with Mr.Tidy's sample code being about 18K at the moment.

Is it worth paying the extra money for an additional 128K you might never use?

Arduino "Tone" command and the ATmega8 - it just won't work

Recently Frits pointed out that sound was used much with robots on this site. I agree and am trying to add sound to a miniature bi-ped robot I am designing. I am now using an ATmega8A processor set up as an Arduino and recently tried using the tone command with strange results. I only get a few frequencies. The digital oscilloscope shows that I am only getting 5 frequencies  which I guess change when the timers prescaler is changed. These frequencies are:

61Hz, 244Hz, 976Hz, 3.9KHz and 31.2KHz

Robots can have children too!

For some time now projects like RepRap have been aimed at self reproducing robots. Although this was not my original goal I have taken a step towards achieving this.

After a few days of trying to get an Arduino to burn the bootloader onto a blank ATmega chip I have finally had some success. As a result, robots lying about my office waiting for repairs are now capable of burning a bootloader into a blank chip.

Burning the Arduino Bootloader with your Arduino as the ISP programmer

I noticed that the Arduino 0018 software included the option of using an existing Arduino as a programmer for burning the bootloader onto blank ATmega chips.Below is my Arduino Nano configured as per the instructions.

This sounds like a great idea but I am having trouble getting it to work in practise. Usually I get this error:

Arduino PWM output frequencies and Tone command

I've been playing with a new oscilloscope Dagu bought after the old one died. I decided to check out the Arduino PWM outputs because I'm using an Arduino in my new speed controller and wanted to check if there were any differences as the brake function requires two PWM outputs to be be in sync so that both input are high or low at the same time.

The PWM outputs on pins 5 and 6 share a timer with timing functions such as millis() and delay() run at about 976Hz while PWM outputs on pins 3,9,10 and 11 run at about 488Hz.

DAGU parts price list for LMR members only

I have now removed the pricelist as we now have distributors in Europe and America.

European customers can buy from: Arexx Engineering or Conrad.

American customers can now buy from Robot Shop.

Should Arduino based robot kits have the Arduino built in?

Now that I'm learning Arduino I've developed 3 Arduino robot kits. The first was fairly big and can take the Arduino Mega, Duemilanove or Nano. The second two have had the Arduino built directly onto the PCB so that little or no jumper wires are needed.

Which is better? The additional cost of the Arduino built in is less than buying an Arduino board and with all the basic wiring done it is much easier for those new to electronics.

From Picaxe to Arduino

When I joined LMR I had just written my first picaxe program. After 16 months I have finally crossed over to Arduino. The biggest problem I found was that all the commands were not in one neat package like the picaxe manuals (Manual 2 in particular).

Dagu is closing for Chinese new year

Just letting everyone know that DAGU will be closing for Chinese new year on the 11th of February. We will open again at the end of February so anyone wanting to order stuff from us may have to wait for a few weeks if they don't place their order quickly.