Lesson 10 – Introduction to Boolean Logic I

Paper Circuits track I is designed to introduce you to various fundamental concepts related to electronics. Electronics is the study of how to control the flow of electrons (sub atomic particles responsible for moving energy around as we know it). Electronics essentially deals with circuits made up of components that control the flow of electricity. Electronics as a branch of science, is a part of physics and electrical engineering.

What is this tutorial about – In this tutorial we will learn about Boolean Logic. We will look at the definition of Boolean logic, how it applies to computers and learn about the “OR” operator part of Boolean Logic. As part of this tutorial we will explore Truth tables and also test out Boolean Logic by creating a paper circuit. We will use the following components to create our paper circuit –

1. Light Emitting Diodes
2. A power source (CR2032 battery)
3. SPST (Single Pole Single Throw) Switches
4. Copper tape
5. Sticky tape

For purposes of this tutorial we will be using use the paper circuit template 7 from the Paper Circuit Track I kit. This circuit will include the use of a SPST (Single Pole Single Throw) switch. With the switch we will be able to turn parts of the circuit on and off just like the physical switches we use at home to turn the lights on/off.

What do paper circuits look like –

Before we get started and create our own paper circuits lets take a few minutes and check out some of these videos to see what others have created using simple paper circuits.

What is Boolean Logic – Named after the nineteenth-century mathematician George Boole, Boolean logic is a form of algebra in which all values are reduced to either TRUE or FALSE. Boolean logic is especially important for computer science because it fits nicely with the binary numbering system (used in computing), in which each bit (used by computers to represent information) has a value of either 1 or 0. Another way of looking at it is that each bit has a value of either TRUE or FALSE.

Boolean Logic is centered around three simple words known as Boolean Operators: “Or,” “And,” and “Not”. At the heart of Boolean Logic is the idea that all values are either true or false. Boolean Algebra is also said to involve bools, or true and false values. These are typically denoted as T or 1 for true and F or 0 for false. Using this simple system we can boil down complex statements into digestible logical formulas.

Boole’s work certainly started modern logic off on the right road. What George Boole did to be recognized as the father of modern information technology was to come up with an idea that was at the same time revolutionary and simple. Check out the following video to learn more about Boolean logic –

Using the various elements provided by Boolean Logic i.e. “Or,” “And,” and “Not”, computer developers can construct logic gates that direct the flow of computing toward various results. Boolean logic and elements like truth tables used to support logical outcomes also reveal the difference between how humans and how computers “think.” The use of Boolean logic can help bridge the semantical difference between machine language, which is simply a combination of ones and zeros, and syntactical code language, which includes elements of human written languages.

Study of Boolean Logic involves the study of truth tables. A truth table is a mathematical table used to determine if a compound statement is true or false. In a truth table, each statement is typically represented by a letter or variable, like p, q, or r, and each statement also has its own corresponding column in the truth table that lists all of the possible truth values. Check out the video below to learn more about Truth tables.

It’s time for an activity –

The first page of the tutorial can be used to practice Truth table concepts. We would suggest you use the Truth table provided to test your understanding of the “OR” Boolean operator.

Once you’ve built your paper circuit using the approach documented below, you should be able to play around with different combinations of SPST Switches to validate your Truth table results above. The paper circuit part of this tutorial is designed to help you learn and validate your understanding of the “OR” Boolean operator.

Components required –

The components required for this tutorial include –

1. 4 x LEDs or Light Emitting Diode
2. 1 x CR2032 coin cell battery
3. 3 x SPST (Single Pole Single Throw) Switches
4. 3 x Diodes
5. Copper tape
6. Sticky Tape
7. Paper circuit template for tutorial 7

Building your paper circuit –

Step 1 – Let’s check out some switches

In this tutorial we will be using SPST (Single Pole Single Throw) switches for the first time. You will fold the switches into shape and place them on top of the copper tape track such that when pressed it conducts electricity through the circuit. Here’s what the SPST (Single Pole Single Throw) switch looks like (see image below).

Here’s (image below) the SPST switch folded up along the dotted lines.

Here’s (image below) the SPST switch lined up within the square lines provided on the track. The SPST switch is lined up within the square space in such a way that when the upper flap is closed shut the copper tape (on the SPST switch) touches the copper tape on either sides of the track forming a complete circuit.

The SPST switch comes with tape on the bottom which you can peel off and stick to the paper once the copper tape has been laid down and the entire circuit tested out. We do not recommend sticking the SPST switch to the paper circuit until you’ve laid down the copper tape on the track and tested out the circuit to ensure it works.

Step 2 – Lay everything out

For this tutorial you will need Paper Circuit template 7. Here’s what that should look like.

Before you get started lay out all your components on top of the paper circuit template and make sure you understand their orientation, placement.

Please Note – The initial version of the kit shipped with LED’s (like the one below) without markings to denote the polarity i.e. Anode/Cathode. As you would know (from our earlier tutorials) that the LED is a type of diode and only will light up when the Anode (positive terminal) connects up to the Positive of the battery and the Cathode (negative terminal) connects up to the negative terminal of the battery. If you have an LED with a dot on it, please ignore the notes in this section.

You should test out the right orientation of the LED before sticking it onto the paper circuit. One way of doing this is to layout the copper tape all along the track, setup the CR2032 battery at the bottom corner aligned with the circle and then test out the LED by placing it at the right spot (in this case right at the top). Try different orientations of the LED and confirm which one lights it up. Only one orientation of the LED will work i.e. LED will only light up when the Anode (positive terminal) connects up to the Positive of the battery and the Cathode (negative terminal) connects up to the negative terminal of the battery.

Verify that your setup looks like that shown in the picture before proceeding to the next step.

See how the SPST switches have been lined up inside the dotted square lines show below.

Each of the paper circuit tutorials comes with two pages, the first page is for you to add your art work and color on while the second page is to be used to create the paper circuit.

Step 3 – Laying Copper Tape

In this section we will start laying copper tape all around the track that’s been marked on the paper circuit template. Please follow the sequence of instructions provided below, else you will end up shorting (connecting or crossing two different lines which should not be connected to each other) your circuit and it will not work.

1. Lay copper tape on track C right upto J
2. Place sticky tape on top of track C as shown
3. Lay copper tape on track A right upto L
4. Place stick tape on top of track A as shown. Track A must safely pass on top of track C passing over the tape laid down in step 2.
5. Place sticky tape on top of track B as shown. Track B must safely pass on top of track C, A passing over the tape laid down in step 2, 4.
6. Lay copper tape on track D
7. Lay copper tape on track E
8. Lay copper tape on track F

Laying copper tape across straight lines is easy but things do get tough when you need to lay copper tape around smooth or sharp corners. Laying down copper tape around sharp corners is a trick and gets easier as you gain experience. You do not have to cut the copper tape at the corner, there’s an easier way to do it. Besides cutting copper tape at sharp corners is going to make it harder for you to create a circuit that is continuous.

Have a look at the video shown below to understand how to lay copper tape around the track following through sharp corners.

Step 4 – Setup the power source using the CR2032 button cell.

1. Lay the CR2032 button cell on circuit within the circle provided.
2. The CR2032 button cell is laid down in such a way that one side of the button is cell is permanently on top of the copper tape.
3. The second side of the CR2032 button cell only touches the other side of the copper tape when you fold the paper, acting as a switch.
4. This setup ensures that power only flows through the circuit and LED lights up when you firmly press the paper with copper tape against the button cell.

Step 5 – Connect up the  LED’s and the Switch to the circuit

Before you can connect the LED’s to the circuit please make sure you’ve oriented the LED’s in the right direction.

1. You should test out the right orientation of the LED before sticking it onto the paper circuit. The dot on the LED signifies the Anode while the other side of the LED is the Cathode.
2. One way of doing this is to layout the copper tape all along the track, setup the CR2032 battery at the bottom corner aligned with the circle and then test out the LED by placing it at the right spot (in this case right at the top).
3. Get the orientations of the LED right and confirm that it lights it up. Only one orientation of the LED will work i.e. LED will only light up when the Anode (positive terminal) connects up to the Positive of the battery and the Cathode (negative terminal) connects up to the negative terminal of the CR 2032 battery.

Once you’ve oriented the LED correctly and tested things out, peel off the white protective strip at the bottom of the LED and stick them to the paper circuit template in such a way that each of the legs of the LED touches one side of the copper tape. Unless the LED is oriented in the right direction i.e Anode (positive terminal) connects up to the Positive of the battery and the Cathode (negative terminal) connects up to the negative terminal of the battery and each of the LED’s legs are touching one side of the copper tape the circuit won’t be complete and the LED’s will not light up.

The SPST switch needs to be lined up within the square space provided on the track. The SPST switch is lined up within the square space in such a way that when the upper flap is closed shut the copper tape (on the SPST switch) touches the copper tape on either sides of the track forming a complete circuit.

Step 6 – Testing everything out and coloring it in

If you’ve got to this point and got your circuit working give yourself a pat on the back.

Once you’ve built your paper circuit using the approach documented above, you should be able to play around with different combinations of SPST Switches to validate your Truth table results you’ve written down on the covering paper. Use a combination of different switch presses to validate your understanding of the “OR” Boolean operator.  Here’s what the results should look like.

• Switch A (Pressed = 1) “OR” Switch B (Not Pressed = 0) “OR” Switch C (Not Pressed = 0) the LED’s should light up.
• Switch A (Pressed = 1) “OR” Switch B (Pressed = 1) “OR” Switch C (Not Pressed = 0) the LED’s should light up.
• Switch A (Pressed = 1) “OR” Switch B (Pressed = 1) “OR” Switch C (Pressed = 1) the LED’s should light up.

Each of the paper circuit tutorials comes with two pages, the first page is for you to add your art work and color on. So go nuts!!! Here’s an example of what you might create.

You’ve successfully built your seventh electronic circuit using LEDs, a power source (CR 2023 coin cell battery), SPST switches, sticky tape and Copper tape. You’ve also learned the basics of Boolean Algebra.

Very well done !!!

About Paper Circuits Track I –

Paper circuits are a great way to get started with the fundamentals of electronics. Simply speaking paper circuits are low voltage electronics circuits that one creates using a combination of paper, conductive copper tape, passive or active electronic components (resistors, LED’s, etc.) including an easy to access power source like a coin cell battery. Educators and parents alike are able to make use of paper circuits to help kids learn relevant fundamentals of electronics by engaging them in hands on activities. Kids create these circuits using the various components provided and through the making learn key concepts. Our paper circuits kits enables kids of all ages with the opportunity to explore fundamentals of electronics without having to worry about damaging expensive electronic boards or components or getting hurt. Paper circuits are a combination of electronics and art bringing together a blend of creativity, learning and experimentation.

Prerequisites –

1. This development track is based on the “Paper Circuit Kit – I” available from OzToyLib
2. Check out the “Paper Circuit Kit – I” and pick one up from – OzToyLib