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Due Dates

Part 1: Wednesday, November 21, 2018

Part 2 Design: Wednesday, November 21, 2018

Part 2: Friday, November 30, 2018

About the Project

In this project, you will be utilizing a 555 timer to power a speaker! The catch is that the speaker must be able to produce a wide variety of frequencies. We'll supply most of the circuit, and you'll be filling in the rest.

If you want to get checked off come to either Kaleb or Bruno (and not any officer).


Please note that you are allowed a maximum of one wire for the soldering portion of this project


  • Make sure to break off your speaker wires and resolder them with better wires that you strip yourself! If you don't, you're gonna have a bad time...
  • If you don't have anything connected between pins 6 and 7, the speaker will not turn on
  • You need a variable resistor in BOTH parts of this project
  • Make sure one note plays for every note. You should not have to press multiple buttons to get a different pitch! Your circuit should funciton like an actual piano in this way
  • There is an optimal way you can design your PIANO so you don't need three different resistor values (you would just need three of the same resistor)
  • Do not solder your variable resistor directly, please use the female headers from the OPS cabinet (cut off the number of pins you need only)
  • If you are having trouble getting distinct pitches on Part 2, try increasing the difference of the resistance between the pitches. Hint: Note that the potentiometer we are using has a range of 100k Ohms, so you can use that as a reference for the resistance to pitch ratio.


DESIGN partial schematic

Part 1

The speaker is powered by an oscillatory wave produced by the 555 timer. Essentially, if we replaced the speaker with a LED, the speaker would make noise every time there is a transition from ON state to OFF state of the LED. How can we change our earlier Blinky LED circuit to fit this requirement?

As you can notice in the Schematic, there seem to be a few things missing within it. As a hint, you'll probably want to look at pins 3, 6, and 7. Look back at our earlier project if you are confused.

Identify 2 ways to change resistance variably, so that the speaker can produce a continuous spectrum of various notes. Look inside the parts in your box and identify which 2 components can fit this job. Remember, we would also like to turn the speaker on and off. Is there a part in your box which will help you do that?

Here are a few links that will help out:

Note: Part 1 checkoff also includes a design submission! This design submission will be how you approach Part 2 below. This is to ensure you will be soldering the correct circuit for Part 2. The design submission will simply be talking about an officer on how you will be doing Part 2.

Part 2

You'll be soldering the circuit in this part. This time there's another constraint: You must have the option of playing 3 distinct note frequencies without physically adjusting any of the variable resistors on the device (i.e. if I play one note and then play the second note, I should be able to play the first note again with ease). You must be able to change these 3 notes. Do not solder your variable resistor or your 555 timer, use a female header and dip socket! Check in with an officer at IEEE before starting this though!


Please note that you are allowed a maximum of one wire for the soldering portion of this project