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This serie of pages on this website will help you on your way with the Parallax (OEM) Basic Stamp II microcontroller.

On this particular page you will find a brief instruction on how to build your own homebrew Basic Stamp II. Keep in mind that this is a VERY brief instruction based on my personal experiences. Read the disclaimer!

Note: This design on the original design by Peter H. Anderson (Jan. ‘98). On his website you can order kits for this: http://www.phanderson.com.

Note: at http://www.osmanardali.com/pcb.htm you can find a very useful single layer PCB for this!

Parallax: Basic Stamp II

Before you start

The Parallax Basic Stamp 2 is a very conveniant way to get started with PIC's,... however, the price can be rather steep. Usually such a package deal costs app. $49 and up.

You can create you own "homebrew" BasicStamp and save some money and makes it attractive for hobbyists and academic users. This approach can be done on a breadboard or on a PCB you (later) create your self.

The kit by Peter Anderson offers all the required part, except for the breadboard, for app. $25. For an additional $2 you get a logic probe which we will discuss later.

Just like the kits from Parallax, it does not include a power supply either. We will need a regulated 5V (DC) powersupply. Make sure the power supply does not exceed 5V as it will otherwise damage the chips! There are lot's of stores out there selling cheap and simple 5V power supplies. You could try for example Conrad.

Assembly time is somewhere between 20 minutes and an hour, depending on your skills.

Required parts

Before we can start creating a homebrew BasicStamp, we will need to get the individual components.

We will need these parts;

Number Part
1
Parallax PBasic2 Interpreter (a Microchip PIC16C57)
1
EEProm (24LC16B)
1
Max232 IC
1
20 Mhz crystal
4
1.0 µF Electrolytic Capacitor
2
20 pF (ceramic) Capacitor
4
4.7 K Ohm resistors (color code: yellow, violet, red)
1
1N4004 Diode
1
Breadboard
1
Powersupply 5V DC

 

Getting Familiar with the parts

Before you can start assembling the kit, you might want to get familiar with the components first;

1.

RESISTORS

The resistors used are 4.7K Ohm (Yellow, Purple, Red - and Gold band). Resistors are polarity insensitive, which means that it doesn’t matter which end goes where.

 

Resistor
Resistor
2.

CAPACITORS

Two 20 pF ceramic capacitors (little brown components with 2 pins) are used. Like, the resistors, it doesn’t matter which way these are installed.

 

Condensator (ceramic)
Ceramic Capacitor
3.

CHIPs

Nearly all ICs have a ‘Pin 1’ marker, that denotes the location of Pin 1. It is important to install chips with the proper orientation!

In the image on the right, the red arrow indicates the orientation notch or dot. The blue arrow indicates pin 1.

 

IC orientation notch (red arrow) and pin 1 (blue arrow)
CHIP/IC
5.

RESONATOR or X-TAL

A ceramic resonator, a brown or blue component with 3 pins, is polarity insensitive. It doesn’t matter which way it is installed, it will still work OK. Install the ceramic resonator on the PCB at the location called "XTAL".
There are also resonators with only 2 pins, which are polarity insensitive too.

Ceramic kristal
X-Tal/Resonator
6.

ELECTROLYTIC CAPACITOR

The electrolytic capacitor looks like a small cylinder with two long pins on one end. The electrolytic capacitor will have the negative lead marked with one or more ‘-’ signs. Install the leg NOT marked with the ‘-’ signs to the plus in the scematics.

 

Electrolytic capacitor
Electrolytic Capacitor
7.

DIODES

Diodes, the 1N4004 in this case, are indeed orientation sensitive. In the drawing below you see the scematic drawing versus the diode drawing. You'' notice that the marking line on the diode matches the vertical line in the scematics drawing.

1N4004: Drawing versus Diode
Diode

1N4004 Diode
1N4004 Diode

 

Scematics and assembly

Below you will find a scematics drawing of the homebrew BasicStamp;

Homebrew BasicStamp scematics
Homebrew BasicStamp scematics

Use this drawing to guide you through assembling the homebrew BasicStamp.

Tip: Usually I print out such a scematic and put it into a transparant sleeve. Then for each connection I make on the breadboard, I draw a line on the transparant sleeve over the connections I just made. This way you can keep track of which connections you completed and which ones still have to be done.

Some notes here:

1. The S1 switch (and the blue colored lines) are optional. S1 is used to reset the PIC if needed. So you can use a simple contact bridge aswell, which you simply shortcut when you want a reset. Or: you simply unplug the power supply, which results in the same effect.
2. Pins 7 and 10 of the MAX232 ic are NOT connected.
3. C1, C2, C3 and C4 are polarity sensitive!
4. The PIC16C57 is the Parallax PBasic interpreter, the largest chip of them all.
5. The 24LC16B is the EEPROM, the smallest chip of them all.
6. The GND - GROUND Symbol-symbol indicates GROUND, which in this case is the same as the MINUS of the powersupply.
7. The PC Serialport connector is usually a so called DB-9 (also Sub-9) or DB-25 (known as Sub-25) connector. This port is being used to program the BasicStamp ones it's operational.
8. Before connecting the powersupply VERIFY the +5V and the GND!

Verifying you homebrew

Using a so called multi-meter or volt-meter (you don't need a high-tech one, just a simple one will do), we can verify if (most of it) is connected properly.

In the drawing below, you will see red balloons indicating the power that should be measured on these point. This drawing shows only that part of the design that is relevant for the measuring points;

Measuring point
Measuring points

 

 


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