Home Chapter 7 BS2 Building the circuit

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BS2 Building the circuit

Parts Required

(1) BASIC Stamp II module
(1) Programming workstation
(1) Board of education
(2) 470 ohm, 1/4 watt resistors (yellow, violet, brown)
(1) Programming Cable
(2) LED’s (light emitting diodes)
(1) 9 volt battery or wall transformer connected to the Board of Education
(6) Jumper wires
(1) Multimeter

Seven important rules for working with electronics and the Board of Education:

  1. Do not add any wires to the board while it is plugged in.
  2. Do not wire one pin to another pin, i.e., connecting pin 0 with pin 1, as this could damage the hardware.
  3. Make sure you are not full of static electric charge. On cold dry days you will notice more static, and be careful if you are wearing wool or polyester sweaters. I always touch metal objects to discharge myself before touching any static-sensitive parts.
  4. Work and play to really understand each lesson before going to the next lesson, as preceding lessons add context and necessary information for lessons that follow.
  5. Turn the Stamp power off so the green LED on the Board of Education is not glowing or on.
  6. Be certain that you are not wearing any metal or long bracelets or watches that may accidentally touch and short out parts.
  7. Do not make any changes to your circuit while the power is turned on.


Prototyping your first circuit

  1. Place the resistor so the leads are cleanly bent at 90-degree angles, and the leads are on opposite sides of the breadboard. Make sure that an accidental movement of the wires will not touch any other wire. It is most important to be very careful when wiring, as two leads or wires touching can short circuit or burn out the Stamp. Start by looking at the 3D model below to get a sense of parts placement.
  2. Place one end of a jumper wire in the pin P0 and the other end in the same row as the resistor.
  3. Slightly pull the LED leads apart and place them in the breadboard, paying close attention to the flat mark on the LED, which helps to identify the direction of the LED in the circuit. The round side connects to the same row that the other end of the resistor is in.
  4. The flat end should be connected to the ground using another jumper cable to complete the circuit.



Below is a schematic for the 3D model shown above. Schematics are drawings of symbols that allow us to see how multiple parts are tied to the Board of Education and our circuit. While the 3D models are very clear, especially to visual thinkers, schematic reading will be a necessary capability for you to develop in order to expand your knowledge of reading schematics outside of this book. When you can read schematics, a vast library of circuit designs will be open up to you. Notice how the LED symbol looks like a diode but has two arrows, which represent light. The ground symbol looks like a rod going into the earth and this is indeed to refer to earth.


Schematic showing orientation of the LED. Notice how the flat mark of the LED is located closest to the ground plane of the BS2 or the same as VSS. The 470 ohm resistor comes out of pin 0 of the BS2