Day 4 - Intro to Transistors and Arduino

• This lab explored how transistors work and required us to assemble several systems with transistors and programmed by the Arduino

1. A transistor is very similar to a relay. There are three pins in a transistor and the pins serve as a collector (where positive electricity flows), base(where electricity may travel to), and emitter (where ground electricity flows). This photo is a visual representation of how electricity flows in both types of transistors PNP and NPN.
2.  We utilized the capabilities through this assembly. 
   
3. Next, we removed the push button and used a human finger as a conductor for the electricity to pass through. It may difficult to tell from the video but when the finger is wet the light shone brighter.
4. For this next part we used a potentiometer and a variable screw resistor to change the current flowing through the transistors. In this picture A1 is on the right side and A2 is on the left side.. Similarly, in this picture A1 is on the right side and A2 is on the left side. 
5. We started at a low current and slowly increased the amount of current that could pass into the transistor. The relationship that was discovered was that the more low the milli amps that were permitted to travel through A1 the higher the gain was measured. Keep in mind that gain = (A2 current) /(A1 current).

• Introduction to Microcontrollers

1. Here is the LED flashing band. For the next part we designed and powered 4 led lights and cycled them continuously. 
1. video

1. code

void setup() {

  pinMode (13, OUTPUT) ; //Initialize Digital Pin 13 as an output

  pinMode (12, OUTPUT) ; //Initialize Digital Pin 12 as an output

  pinMode (7, OUTPUT) ; //Initialize Digital Pin 7 as an output

  pinMode (3, OUTPUT) ; //Initialize Digital Pin 3 as an output

}

void loop () {

  digitalWrite (13,HIGH) ; //Set the LED On

  delay (100);           //Wait for 1000 ms (1 Second)

  digitalWrite(13,LOW);  //Set the LED off

  delay (1000);   //Wait for 1 second

  

  digitalWrite (12,HIGH) ; //Set the LED On

  delay (100);           //Wait for 1000 ms (1 Second)

  digitalWrite(12,LOW);  //Set the LED off

  delay (1000);   //Wait for 1 second

    digitalWrite (7,HIGH) ; //Set the LED On

  delay (100);           //Wait for 1000 ms (1 Second)

  digitalWrite(7,LOW);  //Set the LED off

  delay (1000);   //Wait for 1 second

    digitalWrite (3,HIGH) ; //Set the LED On

  delay (100);           //Wait for 1000 ms (1 Second)

  digitalWrite(3,LOW);  //Set the LED off

  delay (1000);   //Wait for 1 second

    digitalWrite (7,HIGH) ; //Set the LED On

  delay (100);           //Wait for 1000 ms (1 Second)

  digitalWrite(7,LOW);  //Set the LED off

  delay (1000);   //Wait for 1 second

    digitalWrite (12,HIGH) ; //Set the LED On

  delay (100);           //Wait for 1000 ms (1 Second)

  digitalWrite(12,LOW);  //Set the LED off

  delay (1000);   //Wait for 1 second

}

Day 3 - Switches and Relays

• This lab explored how switches and relay can allow or restrict the passage of electricity in a system.

1. A switch connects, severs, or diverts the flow of electricity. This pictured, borrowed from the lab handout, describes how a switch works. Furthermore, here is a schematic of the assembly conducted in the lab. Note that there are two switches in this schematic.  This is the real life assembly of this schematic and here is a video. .
2. In the next part of the lab we assembled a similar system; however, instead of a switch we used a relay. Here is a basic schematic of a relay.  In this schematic there are 4 active areas of interest. The very bottom area, where the coil is located influences the switch in the coil (2nd to top area). When the coil is activated a magnetic force makes the switch move like a lever. To further understand the relay we utilized a schematic that involved the relay.  An interesting concept of the relay in this schematic is that when there is no power from the area that says dc the switch remains toward the bottom; therefore, the led more towards the right will activate. On the other hand, when there is power run through the relay the left led will be activated. Here is how we assembled this schematic.

Day 2 - Introductions to BreadBoard Ohm's law and Potentiometers

• For this part of the lab a led light was assembled by connecting all of the components to a BreadBoard

1. An led such as the one shown in this picture was assembled to the breadboard. Furthermore, this resistor was used in the assembly.  Next, there is a picture of a BreadBoard. Where the blue minus sign and red plus sign are located the components connect the BreadBoard connect horizontal in this picture; on the other hand, in this picture the holes that are next to the numbers are connected vertically in this picture.
   Now, using a separate BreadBoard, the led system was assembled. Power>Resistor>longer side of light bulb>ground 

• In this part of this day's lab we learned about continuity, resistance, and voltage measurements with the multimeter.
• Ohm's law is V=I*R or Voltage=Current*Resistance

1. Here is a picture of the Potentiometer.  OL means that there is no continuity or open loop. O stands for open and L means Loop. Open loop indicates that the positive and ground are not connected; therefore, this indicates that there is no connection where electricity can flow. This is very helpful when soldering a circuit board because it may lead to the discovery of bad soldering.
2. For the next part we attached the multimeter to a battery and measured the voltage of a battery. Notice that in the first picture the settings for the multimeter were on the continuity settings, which looks like a sound wave, and now they are on the voltage settings.
3.  Furthermore, the wall's voltage was measured.  Notice again that the settings for the multimeter are set to ac instead of dc.
4. Next, the resistance of several resistors were measured using the multimeter.   In order to read the resistance the multimeter setting were changed, as shown in this picture, and the ground pin (black) was connected to one end of the resistor and the positive pin (red) was connected to another side of the resistor.
5. Also in this lab, the resistance of Light Dependent resistors were measured. Notice how in this video when light is exposed to the LDR the resistance decreases on the multimeter and when light is restricted from the LDR the resistance value is more high on the multimeter. 
6. In addition the resistance was measured on the multimeter during the use of screw-variable resistor.  In the video the current changes when the resistor is activated.

Day 1 - Soldering and Power Source

• Using a random circuit board, and random resistors and spare parts, we were given the opportunity to practice soldering.

1.  The first step was to gather random items/parts and a circuit board with plenty of room to solder the parts onto the board. 
2. Next, we had to heat up the soldering device to 600 degrees Fahrenheit and then place the circuit board, item that we wanted attached to the circuit board, soldering pen tip, and solder all at the same spot until the solder melted and bonded the circuit board and the item. The green part of the board where the copper was visible was the side where the solder was melted down to connect the components. In addition, using the pliers shown in this picture, the ends left on the green side were trimmed to ensure that there would be adequate space.

• In the other part of this lab we were given a power source and had to solder wiring to it for later use.

1. Using a phone charger, we cut the end that would normally plug into the phone with pliers.Next using a multimeter we tested which wire supplied the positive charge and which one was ground or negative.
2. After securely soldering the cables with red as positive and black as ground we used heat shrink tubing to secure the wiring in place and prevent it from tearing apart. The heat shrink tubing was placed around the areas where wiring was attached and then it melted the tubing to the wiring. The heat gun for this part of the lab was extremely hot and the wire along with the tubing was only placed over the heat for a few seconds.
3. Here is the end result.