BASIC Stamp

The BASIC Stamp is a microcontroller with a small, specialized BASIC interpreter (PBASIC) built into ROM. It is made by Parallax, Inc. and has been quite popular with electronics hobbyists since the early 1990s due to its low threshold of learning and ease of use (due to its simple BASIC language).

Technical Specifications

Although the BASIC Stamp has the form of a DIP chip, it is in fact a small Printed Circuit Board that contains the essential elements of a microprocessor system:
* A Microcontroller containing the CPU, a built in ROM containing the BASIC interpreter, and various peripherals
* Memory (a serial EEPROM)
* A clock, usually in the form of a ceramic resonator
* A power supply
* External input and output

The end result is that a hobbyist can connect a 9 V battery to a BASIC Stamp and have a complete system. A connection to a personal computer allows the programmer to download software to the BASIC Stamp, which is stored in the onboard memory device. This memory stays programmed until it is erased or reprogrammed (the memory remains intact even when the power is removed).

Programming

The BASIC Stamp is programmed in a variant of the BASIC language, called PBASIC. PBASIC, incorporates common microcontroller functions, including PWM, serial communications, I²C and 1-Wire communications, communications with common LCD driver circuits, hobby servo pulse trains, pseudo-sine wave frequencies, and the ability to time an RC circuit which may be used to detect an analog value.

Once the program has been written, it is tokenized and sent to the chip though a serial cable.

Versions

There are currently four variants of the interpreter:
# BASIC Stamp 1 (BS1),
# BASIC Stamp 2 (BS2), with six sub-variants:
## BS2e
## BS2sx
## BS2p24
## BS2p40
## BS2pe
## BS2px
# Javelin Stamp
# Spin Stamp.

The BS2 sub-variants feature more memory, faster execution speed, additional specialized PBASIC commands, extra I/O pins, etc, in comparison to the original BS2 model. While the BS1 and BS2 use a PIC, the remaining BASIC Stamp 2 variants use an Parallax SX processor.

The third variant is the Javelin Stamp. This module uses a subset of Sun Microsystems' Java programming language instead of Parallax's PBASIC, it does not include any networking facilities.

The fourth variant is the Spin Stamp. The module is based on the Parallax Propeller and therefore uses the SPIN programming language instead of PBASIC.

A number of companies now make "clones" of the BASIC Stamp with additional features, such as faster execution, Analog-to-digital converters and hardware-based PWM which can run in the background. However, while many use the same pinout as the BASIC Stamp in order to be hardware-compatible in larger-scale projects, they are not necessarily software-compatible.

The Parallax Propeller is gradually accumulating software libraries which give it similar functionality to the BASIC Stamp, however there is no uniform list of which PBASIC facilities now have Spin equivalents.

See also

* Arduino
* Make Controller Kit
* OOPic
* PICAXE

External links

* [http://www.basicmicro.com BasicATOM pin compatible with the 24-pin BS2]
* [http://www.c-stamp.com C Stamp 48 pin only]
* [http://www.comfiletech.com/index.asp?PageAction=VIEWPROD&ProdID=139 CB220/320, an AtMega128/2561 based board, pin compatible with the 24-pin BS2]
* [http://www.coridiumcorp.com/ARMexpress.php ARM based Stamp, pin compatible with the 24-pin BS2]
* [http://www.emesystems.com/BS2pbasic25.htm "Comparing PBASIC 2.5 control structures to the old PBASIC"] – By Tracy Allen, EME Systems, 2003
* [http://forums.parallax.com Parallax Forums] – Discussion Forum
* [http://www.parallax.com Parallax, Inc.] – Corporate website, home of the Basic Stamp and Basic Stamp 2
* [http://www.zbasic.net ZBasic Microcontrollers] – several AVR-based Stamp replacements, pin compatible with the 24-pin BS2
* [http://www.arrickrobotics.com/arobot/ Mobile robot] – utilizing the BS2 chip, also the subject of "Building Robots for Dummies"
* [http://www.andybrain.com/extras/scribbler-robot-review.htm "Independent review of the Scribbler Robot, a programmable intelligent robot utilizing the BASIC Stamp 2 Microcontroller"] – By Andy Kaiser
* [http://www.parallax.com/dl/docs/article/IlBASICStamp2.pdf "Il BASIC Stamp® 2 - Un microcontrollore dalle dimensioni di un francobollo"] – By Giuseppe Francesco Indelli, published in the Italian language as an introductory article to the BASIC Stamp 2 microcontroller.