II: Basic tools, procedures, and electronics

Measure voltage in a circuit with a multimeter and with Arduino analogRead

1.With a multimeter

You can see the voltage decreases along the direction of the current. And different bulbs have various voltage since their colors are not the same, which means that they need to release different amount of energy during shining.

2.With Arduino analogRead

You can see the number shown on the computer screen. 1023 represents 4.33v and 419 represents 2.11v in the picture above. 0 just represents that there is no bulbs or resistors remaining in the direction of current. The circuit diagram in the blackboard shows the decreasing of the voltage in a circuit.

If you also want to measure the voltage with Arduino, just Open the Arduino and Find the AnalogReadSerial example in the Files.

Ohm's Law

Since we’ve already measured the voltage in a circuit, we needed to figure out some physics principles behind it. That’s Ohm’s law.

Lab Time, June 28

1.Measuring & Cutting

We needed to have a cardboard which is fitted to the Laser Cutter, but the cardboards we had were too big to place into the Laser Cutter working table. As a result, we measured the working table and drew lines on the cardboard according to the size of the table. To measure the size of different kinds of things, we used the meterstick or caliper. The next step is cutting the cardboards with box knives. After using the box knife, we were supposed to check whether the blade was dull or not. If it is, it’s our duty to change to a new blade and dispose the dull one in “Sharps” box.

2.Sawing & Drilling

After learning some ways to process the cardboard, we started to deal with wood and metal. For wood, there are two different saws: Push and Pull. You could feel the difference between them when you put you weight on the saws. And you need to remember that you’d better use a sharp saws rather than dull saws since dull saws are even more dangerous. For soft metal, the saws could saw both during pushing and pulling. I love the feeling of sawing a Aluminum.

For drilling, you are supposed to remember four things before you start: Loose clothing/hair, Eye protection, Drill chuck safety, Clamping. It’s really satisfied to operate a drilling machine since you can see the beautiful patterns on the metal surface. We still choose to use Aluminum at this time.

3. Joining

Because we’ve already cut some pieces of diffrent matrials like aluminum, and we’ve also drilled some holes in the plastic board. So our next step is to join them together. In order to join these two materials, we need to use the glue. We choose the super glue instead of the wood glue or white glue because of fast settinng. With this glue, they could be joined together in seconds rather than for thirty minutes. At the same time, it’s importannt to put the aluminum into the hole with the similar diameter.

4. Experiencing AR to measure the voltage in the circuit

In the class, we are able to experience the AR to measure the voltage in the circuit. This is a new thing for everyone since theis equipment is still be in research stage. Fortunately, we have a chance to experience it first. The computer screen shows what you will see after wearing the AR glasses. There are four images on the screen, which represents that it could read the voltages of four different position in the circuit simultaneously. But firstly, you need to start up the system via gesture. It’s really interesting because the gestures are really vivid that makes you believe that it’s real. That’s exactly what AR means-Augmented Reality. For example, if you want to click somewhere, you just need to do a gesture of clicking in front of your glasses. It’s really convenient. It’s a pity that I can record what I saw through my glasses. But I love this equipment very much.

Summary:

In the class, the teacher leaded us to do some easy experiments to find out Ohm’s law. The learning way was really different from the Chinese learning way. When I learnt the Ohm’s law in China, I just needed to remember the formula written in the blackboard instead of doing experiment to find it. Honestly, I love American way much.I hope I could do well in the classes of next week.

During the lab time, we learnt some basic skills that an engineer should handle. Because I never do them in China before, I was really curious and excited about them. Fortunately, I did a good job and I felt that I was more interested to be an engineer. When I’ve successfully done every task, I was pretty satisfied. At the same time, when experienced the AR to observe the voltage in the circuit, I felt that I was the Iron Man. I enjoyed seeing virtual images in front of my eyes and reading the parameters in them. I even started thinking about being an engineer in AR. At the end of the lab time, I had a chance to talk about my final project with Somia. Thanks for his advice, I started making my prototype cars. I really expect the next lab time now.