It's tempting to dive right into robot navigation. We understand! But, as with any vehicle, it's wise to get familiar with the controls before attempting to drive.
In this section you will:
Take a quick tour of the Propeller Activity Board (original or WX version) to get acquainted (or re-acquainted) with its feautres. You've already connected cables to the servo ports and have plugged the battery pack into the power jack. You've been programming it a bit already, so you have been using the USB port.
Next, let's take a closer look at two features in particular: the power switch and the breadboard. These features are found on both versions of the Activity Board.
All versions of the Propeller Activity Board have a 3-position power switch:
The breadboard lets you build your own circuits with common electronic components. It's a great way to learn about electricity, and to experiment with making your own inventions. Building experimental circuits to design your own projects is called prototyping, and it is a real-world engineering skill.
The Activity Board's breadboard (original or WX version) is surrounded on three sides by black sockets. These make it convenient to connect circuits on the breadboard to power, ground, and the Propeller I/O pins. There are also sockets to connect to a digital-to-analog converter and an analog-to-digital converter.
Welcome back! Did you watch the video? If you did, you now know why it's called a "breadboard." History can be pretty interesting!
Next, let's test-drive two built-in light circuits on your Activity Board.
Your Activity Board (original and WX version) has two built-in lights, near the bottom-right corner of the board. These tiny light-emitting diodes (LEDs) are already electrically connected to I/O pins P26 and P27. These LEDs are helpful when developing applications that use sensors. The idea is to write your program so that if a sensor is activated, an LED lights up to give you, the roboticist, a quick visual cue that the sensor is actually detecting something.
The Simple Circuits tutorial has an example program for blinking these LEDs.
Welcome back!
Even though the Propeller chip can play WAV files and synthesize speech, sometimes a simple beep is all the noise you need to get the job done.
The first breadboard circuit we'll build for the ActivityBot is a simple piezo speaker.
It is very easy to make this speaker beep with a single line of code:
freqout(4, 1000, 3000); // pin, duration, frequency
You can optionally add this line code at the beginning of your ActivityBot example programs. Then, If your robot's batteries run low, the Propeller microcontroller will reset and restart the program—the beep will let you know if this has happened. We include it because it can be very helpful when experimenting with navigation programs, and trying to figure out why your robot is behaving in an unexpected manner.
Welcome back!
Well done! Now you are ready to go on to robot navigation.
Links
[1] https://www.parallax.com/downloads/propeller-activity-board-wx-product-guide
[2] https://www.parallax.com/downloads/propeller-activity-board-guide
[3] https://learn.parallax.com/reference/breadboard-basics
[4] https://learn.parallax.com/propeller-c-simple-circuits/blink-light
[5] https://learn.parallax.com/propeller-c-simple-circuits/piezo-beep