Let's Make Robots!

Mr. General

  • Component category:
Mr._General_4.bas16.45 KB
Tone.zip9.68 KB
Mr__General_ATmega8_Edge_Detect.zip3.23 KB
Mr__General_ATmega8_Object_Detect.zip3.25 KB
Mr_General_Nano.zip3.21 KB
Vendor's Description: 

Video: http://www.youtube.com/watch?v=7Ve318yVUdU

DAGU products support site: https://sites.google.com/site/daguproducts/

This kit has recently been upgraded to include a USB interface, programming cable and the ATmega8A processor with the Arduino bootloader. The Manual has been updated with wiring instructions and diagram as well as USB driver instructions and trouble shooting section.

An improved "Tone" library is included on the CD as well as being available here that allows the Tone command to function on the ATmega8 processors (thanks to Robot Freak and Brett Hagman).

Based on Bot 08M, Mr. General is designed around a breadboard and includes the universal sensor brackets designed here at LMR as well as my IR object tracker in the form of a compound eye.

The Picaxe code was written for the picaxe 28X1 processor. The first Arduino code was written for an Arduino Nano which has 8 analog inputs. The second Arduino code is for an Arduino with only 6 analog inputs. This version uses digital inputs for the corner sensors which gives them slightly less range.

An IR LED and phototransistor is mounted on each corner and can be used for edge detection or object detection depending on how you choose to mount them. When mounted for object detection they can also be used for swarm communication. These sensors have an analog output but can also be used with digital inputs.

Here are some videos using a picaxe 28X1 and here is a video from GuangZhou University using the compound eye and an arduino to solve a maze.

The compound eye allows your robot to track a moving object but can also be used for IR communication between two robots. Other range sensors could also be fitted to the sensor bracket.

2 factory modified, continuous rotation servos allow speed and direction of each wheel to be controlled by a single digital output.

The kit does not include a micro-controller as the breadboard allows a wide variety of processors to be used. A generous 140 piece cable pack allows easy connection between the breadboard and sensors.

2 individual voltage busses allow for up to 3 different voltages plus ground to be used. Ideal for 3.3V devices and op-amps. A basic recharge circuit allows NiMh or NiCd batteries to be charged from a 9V DC source without being removed from the robot.

All spare room on the main PCB is configured as prototype board as show in the picture below. This allows additional sensors and circuitry such as voltage regulators to be easily added.


Of course being designed with parts from LMR it is only fitting that we have the LMR logo on the box.

 Click on the photo for a bigger picture.





More information can be found here: http://letsmakerobots.com/node/24348



Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.

Hello OddBot,

This is my first robot and I am having alot of fun.  I'm using a different microcontroller then you atmegga644 instead of the atmegga 8 and its max current is less then the atmegga 8 but there is so much noise on the power line that I'm having troble getting consistant ADC readings. I plan on adding a voltage regulator to the design but I'm having trouble finding space on the bread board.  Anyways I just thought I share the suggestion if you wanted to add it to a future update.  Besides this robot is giving me the confidence to move on to bigger projects.

There is a small prototype area where you can solder a voltage regulator.

It is quite likely you will get noise anyway because the parts are in a breadboad. The MCU itself generates a lot of noise. Try adding a 100nF or 220nF monolithic capacitor as close as possible to the MCU power pins. You should find this makes a big improvement.

I would be asking a "Beginners question"


did you involve the total circumference of both wheels(to calculate the distance in each movement of the modified servo) to do the program.?

or anything informations about the wheels of Mr. General.. cause i felt conscious about its wheels, and i want to make sure about little stuffs.


I don't fully understand your question.

There are no calculations at all involving the wheel diameter or distance relative to each other. Distance is not calculated on this robot. It simply adjust motor speed and direction in response to the IR sensors in the eye and on the corners.

that thing is what I really wanted to be sure.. thanks!

To begin with you have plugged the MCU in upside down!

Please check your wiring very carefully here: http://letsmakerobots.com/node/24348

Make sure you are using NiMh batteries to provide 4.8V as Mr. General does not use a voltage regulator and will not work reliably with Alkaline batteries.

Hi, I bought my son the Mr General kit for his science project. The box didn't come with a ceramic resonator, 10k resistor or 100nf capacitor. The manual didn't even show them as parts. Then on the wiring instructions page, the're mentioned and I see them in the pictures. I only have a 10uf capacitor. The kit did come with the USB interface, programming cable and an ATmega8A processor. Please advise. Thanks

The original kit does not come with those parts as it was designed to work with any processor. The idea being that you supply your prefered MCU, programming cable etc.

I did later try to update the kit to include the ATmega8A and the components you mentioned but most distributors were not interested because it raised the price.

Because of this I wrote this tutorial: http://letsmakerobots.com/node/24348

You can choose to use a Picaxe processor or an Arduino compatible ATmega MCU. I have provided wiring diagrams and sample code for both.


Sorry, I wasn't clear and I'm new to robots and electronics, so please bear with me. I do have the ATmega8A and USB interface. That came with the kit. Do I still need what you mentioned? Do I also need the ceramic resonator, 10k resistor and 100nf capacitor with the ATmega8A? Will the robot function ith what I have? Thanks again.

OK. I do not know why the other parts are missing because you do need them to make it work.