The Learning Circuit s01e03
Titre original : Wigglebots
To build your own Wigglebot, all you need is a battery and a motor. Karen pulls out some DC motors that she's taken out of some common objects. She's pulled a DC motor out of a cheap electric toothbrush that she found at the dollar store, some motors from video game controllers lying around the shop, a motor from a cell phone, and a computer fan. The computer fan won’t work as is, they’ll need to break some of the fan blades off so that it’s off balance. Vibrating motors work like DC motors, but a weight is placed on the end causing it to vibrate when it spins. Once you've found your motor, make sure that your battery has enough voltage to make it run. A lot of motors have an optimal rating, but a lot of times you can use a different voltage, such as a 9 volt battery to run a 12 volt fan. When you are connecting your motor to your battery pack, make sure your ends are long and stripped. Once your wires are twisted together be sure to cover it in electrical tape. This will keep it together and help prevent red wires from touching black wires. You don't want the red wires touching the black wires because that will cause a short and make it not work. You can then decorate your Wigglebot using stuff around the house such as pipe cleaners, pom-pom balls, popsicle sticks, paper clips, and googly eyes. You can even use electrical parts like old resistors, whatever you have lying around the house. For kids looking to do more, kick it up a notch by adding a capacitor. Both capacitors and batteries store electrical energy but work in completely different ways. Batteries have two terminals, chemical reaction inside the batteries produce electrons on one terminal and absorb electrons on the other terminal. Capacitors cannot produce electrons, they can only store them. Capacitors usually have two ratings, voltage and something called farads, a unit of measurement of capacitance. For this project, select a capacitor that is rated for approximately the voltage you'll be using, and has high capacitance. For example, Karen is using a capacitor that’s rated for 5 farads and 2.7 volts. In this new circuit, they’re going to replace the battery with the capacitor. Because the capacitor only stores energy, they'll need to get energy to it by hooking up a battery to their circuit. They can then connect the capacitor to the motor. To build the circuit they're going to use a breadboard. Karen pulls out three different types of breadboards. The first one is a tiny breadboard with the numbers 1 2 3 at the bottom of the columns. This is there so that you know that each of the columns is connected. The next one has five holes that are connected on the left side and 5 that are connected on the right. The left side and the right side are not connected. A more traditional breadboard has power rails on the side. They still have their rows of 5 holes connected on the left and the right side but up the far sides there are power rails. On this breadboard, all of the holes in the column next to the red line are connected and all of the holes next to the blue line are connected. They are intended to be used for power and ground. She’s going to use the tiny breadboard for her circuit. She’s plugs in the motor and then the capacitor. She wants one of the leads of the capacitor to be in the same row as one of the leads from the motor. Using two jumper wires, she plugs one into the same row as the second lead of the capacitor. The other one she’s going to plug into the second lead of the motor. She can then use a jumper to connect the two of them to complete the circuit when she’s ready to use her capacitor as her power source. Once her circuit is all set up all she needs to do is plug a jumper on to connect the two wires. Before she does that she needs to make sure that she charges up her capacitor so that it can actually power the motor. She plugs the leads of the battery into the breadboard to charge the capacitor.