The Breadboard, or solderless breadboard as it is properly called, is an easy way to connect electrical components together without soldering them. Electrical components are plugged into the breadboard and connected via little metal channels that run beneath the surface. The picture below shows how connections are made on the breadboard.

What follows is information about the power supply and PICAXE software that will be used in the subsequent steps of this Guide to Building a Small, Autonomous DC Robot.

Power:
Use 3AA batteries or, a 5 V regulated power supply, or 3 AA batteries.
(Keep reading to find out how to hook up a 5V regulator.)
Never connect the PICAXE to more than 5 V or it will be destroyed.

The Software:
System requirements – Computer must be running Windows 95 or later and have about 25 MB of free space on the hardware.

Installing the Software:
1)Download and run the installation file from www.picaxe.co.uk
2)Follow the on-screen instructions.
3)Plug PICAXE into the computer with a 9 pin serial cable.
4)To start the software, Click Start>Programs>Revolution Education>Programming Editor
5)If the Options menu doesn’t automatically appear, click on View>Options menu. Select the type of PICAXE on the mode tab. Select the Port tab to select the COM port.

The PICAXE

Most microcontrollers are made with the assumption that the person using them will be an experienced electrical engineer. The PICAXE is been created specifically with the novice user in mind. The PICAXE is much easier to use than most microcontrollers for a couple reasons.  It can be programmed in the BASIC Programming language which is easier to learn than assembly language.  There are special software commands making it easy to program the microcontroller to perform useful tasks.

The PICAXE does not require a compiler or EEPROM burner to be programmed. All that is needed is the Programming editor, a nine pin serial programming cable and an interfacing circuit that requires only a couple resistors. This is all possible because a PICAXE is really just a “ pic “ microcontroller that has been loaded with a bootstrap program. The bootstrap program allows the PICAXE to communicate with the PICAXE programming editor to be programmed easily by the novice user.

The Hardware: PICAXE-18X

I/O: The PICAXE-18X has 9 outputs and 5 Inputs. Inputs 0-2 have analog to digital converters.

Memory: The PICAXE-18X can hold a program with about 600 lines of Code.

Special Functions: The PICAXE-18X includes Interrupts, infra-red receive, Servo control, keyboard input, support for digital temp sensor, i2c interface, 8/10 bit adc option, pwm motor control input pulse counting, serial output via programming cable.

Here is a picture showing how to hook up the PICAXE 18X on breadboard. The Voltage regulator circuit need not be included if the power source is less than 5 Volts.

Microcontrollers
Microcontrollers are programmable computer chips. A single chip contains a processing unit, memory as well as inputs and outputs. The processing unit executes the list of instructions that the computer programmer has loaded into the microcontroller’s memory. The inputs of the microcontroller are connected to devices that allow it to sense the environment and the outputs control electrical devices. The program in the microcontroller determines how it will use sensors to collect information about its surroundings and what the output devices will do in response to the environment. Some examples of input and output devices are illustrated below.

Input Devices Output Devices
Push Buttor or Whisker Light Emitting Diode (LED)
Potentiometer Seven Segment Display
Photoresistor Liquid Crystal Display
RF-Reciever Speaker
Photoresistor Relay
Accelerometer Motor
Infra-Red Reiever Muscle Wire
Temperature Sensor RF Transmitter
Intra-Red Transmitter

Microcontrollers are all around us. They are in clocks, calculators, cars, microwaves, TV remotes, video game controls, gas pumps and computers, just to name a few. In most robots a microcontroller serves as the brain.

Using the PICAXE Programming editor, you can download a list of instructions into the microcontroller to make it do things. By learning how to program a microcontroller and interface it to input/output devices you become an inventor. You Can download the PICAXE programming editor from their website.

I am just getting started with this blog intend to help people just get started with robotics. The goal of this blog is to explain how to build and experiment with cheap programmable robots using the PICAXE micro-controller. Comments and recommendations are welcome.

I got my start in robotics working with the the BASIC STAMP. The PICAXE is a cheaper micro-controller that is not quite as powerful. Both are excellent for introducing the beginner to the world of microcontrollers.

Next Entry: – ) “What’s the Deal with Microcontrollers?”

Here ends my first entry,

Bill

This blog is intended to help people get started building their own robots.