Here are some resources I've found useful in the past when building robots. If you have any suggestions or additions, e-mail me: firstname.lastname@example.org
- Digikey - they have everything and have great service, there is no problem dealing with them as an individual
- Allied Electronics - good service, they are a little more geared toward a corporate customer
- Newark - I've had mixed experiences with their service, they are a little more geared toward a coporate customer
- JDR Microdevices - their selection is a little more limited, there is no problem dealing with them as an individual
- Jameco Electronics - OK service, there is no problem dealing with then as an individual
- Circuit Specialists - lots of kits and parts and PIC related stuff
- Amazon Electronics - lots of kits and parts and PIC related stuff
- All Electronics - a source of surplus parts
- Mouser Electronics - a good source of parts
- Abacom Technologies - look reasonable and are relatively low cost, I have not used them personally
- Radiometrix - look reasonable and are relatively low cost, I have not used them personally
- Alberta Printed Circuits - a company which can manufacture prototype printed circuit boards, a little pricey, but I was happy with their service
- Supercircuits - a company which sells small video cameras and wireless transmitters - mostly for covert surveillance
- Polaris Industries - a company which sells small video cameras - their catalog has more technical info
- McMaster-Carr - their catalog contains everything under the sun, a little more geared toward the coporate customer
- Small Parts Inc. - I've never ordered from them myself, but I know they have a good selection of drive system related components
- Stock Drive Products - I've never ordered from them myself, but I know they have a good selection of drive system related components
These motor manufacturers make "real" DC motors, of course you can get a motor for $1.50 somewhere - but it won't be able to output very much torque, it won't hold up over time, and will generate a lot of electrical noise.
Hobby Servo Motors
- Pittman - they manufacture motors with integrated gear boxes, they make reasonable quality motors and some models are available for reasonable prices
- Micro Mo Electronics - they manufacture motors with integrated gear boxes, their motors are of very high quality and demand a premium price
Hobby servos where originally intended for controlling R/C (remote control) cars and airplanes. But they are have been amazingly useful for robotics hobbyists. That is because they contain a small motor driver and servo controller. The input signal is a PWM signal which tells the internal electronics where the motor should be positioned. Internally the servo driver electronic has a potentiometer on the shaft to provide it with feedback about the shaft position. Originally only made by Futaba, a variety of companies now make these servos. They are available in many sizes and strengths. Some have plastic gears and others (more expensive) have metal gears which make them stronger. In general servos are great for experimenting and are quite reliable, but in any situation where the robot has to run for an extended period of time - "real" motors may be a better choice. Servos, because of their low cost, have limited lifetimes in load bearing applications.
- Tower Hobbies - a general R/C hobby supplier, but their prices are kind of high
- Lynxmotion - sell the MiniSSC II Servo Controller as well as a bunch of other parts for hobbyist robot building
- Scott Edwards Electronics - they sell and manufacture the MiniSSC II Servo Controller as well as a serial LCD interfaces
- Jameco - they sell the MiniSSC II as well as another cool servo controller which has a lot more functionality, but is twice the price, so if you really just need quality servo control, I would go with the MiniSSC II
- FerretTronics - cute single chip servo controllers
Stepper motors are special kind of motors which move in discrete
steps. When one set of windings is energized the motor moves a step in
one direction. When another set of windings is energized the moror
moves a step in the other direction. (A holding current is also needed
to maintain position if the motor is subjected to some external force.) The
advantage of stepper motors is that because they move in discrete
steps, the position of the motor is "known" without a feedback device.
Knowing the position of a stepper motor is possible if a known zero
position can be determined. This is usually accomplished by some
combination of a limit switch and a mechanical stop. The disadvantage
of a stepper motor is that it usually draws more power than a standard
DC motor and requires a little bit of work to drive properly. Another
disadvantage is that since there is no "real" feedback the actualy
position of the motors can be lost if the motors "skip" a step. (And
they often do.)
Brains for Bots
The Basic Stamp
In the last couple of years this controller has become very popular. It is based on a PIC microprocessor with a basic interpreter built in. It is relatively inexpensive, easy to use, and a lot of code is laying around because some many people have been hacking on it.
The 6811 Microprocessor
- Parallax - they are the original inventors of the Basic Stamp and have a number of more advanced versions now, they also have links to a couple of customer projects
- Radio Shack - what could be easier than strolling down to the corner store to buy a Parallax Basic Stamp, unfortunately they do not sell the more recent versions of the Stamp
- Lynxmotion - they sell the original Basic Stamp was well as some clones
- Micro Mint - they have a number of clones which are more powerful with more features which they call the PicStic
This microprocessor made by Motorola has been the work horse of robotics hobbyists for many years. This is an amazingly cool chip, most versions have on board A/D, EEPROM program memory, are in circuit programmable and are just a pleasure to use. A variety of boards are available which utilize the 6811.
The PIC Microprocessor
- The Handy Board - a board developed at the MIT Media Lab, generally useful including a motor driver and other goodies and programmable in language called Interactive C
- 6811 FAQ - a faq, what else were you expecting?
- Interactive C - an excellent robot programming language
This microprocessor made by Microchip. Most models aren't as flexible as the 6811, but they are small and RISC based so they are relatively fast. There is even an 8 pin version. The newer models which have a good amount of flash memory and a bunch of built in peripherals make them quite an attractive development choice.
- Atmel - 8 bit RISC, 8 pin models available
- Scenix - the virtual peripheral concept is cool, used by Parallax in newer Basic Stamps
- 80C51 - a processors which has been around for a long time, very popular in industrial applications, originally developed by Intel
- 6805 - another processor which has been around for a long time, used in industrial applications, originally developed by Motorola
- COP8 - National Semiconductor's entry into the low end microcontroller market, billed as being very low cost
This is a standard for (typically) x86 motherboards and a stackable expansion bus which are relatively small (4"x 4") which have been very useful in embedded systems applications and hence robotics applications. They are the right way to go if you want to have the computing on board your robot - but this is a pricier approach than using a simple microcontroller as the sole on board processor or an RF link.
The Card PC
This is a way cool device, but mighty expensive. It is an entire PC in a PCMCIA sized package. It is made by Epson. Everything is included, RAM, flash ROM, serial ports, etc. However, the connector is not a PCMCIA connector (there are too many pins) and a PCMCIA card interface is not built in.
The DIMM PC
This takes the Card PC concept one step further and smaller. It is an entire PC in a DIMM sized package, 2.7" x 1.7" x 0.25". It is made by JUMPtec. Everything is included, RAM, flash ROM, serial ports, etc. Someone even has Linux running on it and is hosting a web site with it.
Robots for Hobbyists
General - distributors, kits, etc.
PC Controllable - meant to be interfaced to a PC, typically via RF Modem
- Pioneer - a higher priced, but very functional robot, available in an RF modem version and a standalone version
- The ARobot and The Trilobot - basic robots from Arrick Robotics
- Gecko Systems - the CareBot personal care robot and vacuum cleaning robot, a mid size robot
- Personal Robots - the Cye robot, a small slickly packaged hobbyist robot (aka www.rugrover.com)
- Circuit Cellar Ink - a great magazine which focuses on emebeded control projects, some articles are aimed at the advanced beginner, others a little higher
- Robot Science and Technology - a magazine aimed at the robotics enthusiast, I've never seen a copy myself
Robotics Research Labs