Introduction to Robotics/Electrical Components/Lab/Teachers
Each group of students is going to need the following components:
- Voltage/current/Ohm meters, or a DMM
- Power supply
Some instructors may wish to introduce the students to the concept of soldering. This is useful because it's a practical skill that future engineering students will make use of. However, because the BoeBots come with breadboards, soldering won't be a useful task unless the student wants to create a very complicated circuit for their final projects.
If the instructor does decide to teach soldering, the lab should begin with a lesson on techniques and safety. The instructor should ensure that students who are soldering be properly supervised.
An optional portion at the end of the student lab assignment about soldering has been added. The instructor should feel free to remove this section if soldering will not be covered, or modify it if different projects are going to be used.
The instructor may choose to do some of the laboratory work using simulation software such as PSpice or Electronics Workbench. Simulation is a good idea, especially if a large number of examples need to be worked through in a limited amount of time, or if the prototyping hardware available to the students are of low quality.
Students should be exposed to some physical circuit construction using breadboards, because all circuits on the BoeBot will be constructed in this way.
We want to introduce the electrical equipment, and demonstrate how to use the meters to measure voltage, current, and resistance.
When measuring various circuit quantities, make sure to reiterate these points:
- Measure voltage across an element.
- Measure current at a break in the circuit, never across an element.
- Take care not to short your circuit with your probes and wires.
In terms of safety, it is important to reiterate this point: 2 amps of current is enough to kill a person. 1 amp of current is enough to injure a person. When working with circuits, make sure students understand not to play with the power source, and to always use appropriate resistance to keep their current under control.
Some students will want to know why we must break a circuit to measure the current. Repeat the point that an Amp-meter has zero resistance. Point out that the power supply is at a constant value, such as 5 volts. Now, ask the student:
- You have 5 volts and 0 Ohms resistance, what is the current?
Let the student think about it, and if they appear confused, repeat for them Ohm's law: V = I R. Let the student try to solve the equation on paper, if needed, but let the student come to the solution on their own: With zero resistance, the amount of current going through the ammeter will approach infinity, and infinity is bad.