Quick Makes

Drawdio

Learn It

  • We can create different tones by creating different frequencies.
  • In the previous project(The Egg Timer) you learned about 555 timer circuits.
  • These circuits can produce pulses which change the frequency.

Try It

  • Look at the video below to see how the frequency changes when you adjust the resistance.

555circuit.jpg

  • Try building the circuit above using circuit wizard.
  • Change the values of VR1 and see how it affects the speed at which the LED flashes.

Build It

  • Below is the full circuit diagram. if you have time, you can try design one yourself.

Drawdiocircuit.png

  • Your circuit board will look like this. Please note, the LM741 is actually a TDA2822M
  • This will need to be replaced.

DrawdioPCB.jpg

  • As usual, always start building with the smallest components first (the resistors).
  • Once you have finished your PCB, it should look like this.

CloseDrawdio.jpg FullDrawdio.jpg

  • Below are some close-up pictures of how to connect the buzzer and switch.

BuzzerDrawdio.jpg SwitchDrawdio.jpg

Build It

  • Now you need to attach your Drawdio to a pencil.
  • First file down the end of the pencil.
  • Be very very gentle, or you will break the pencil.

Filepencil.jpg

  • Now attach the copper tape to the top and bottom.

Tapepencil.jpg

  • You can now attach the board and solder the wires to pencil and neaten up the board.

Solderpencil.jpg

  • Time for testing.

Completepencil.jpg

Badge It

Silver

  • Paste a screenshot of your 555 timer circuit you designed and paste it into the word document (Or upload the picture directly).
  • Explain what happens to the frquency when you change the resistance value.
  • Explain how the change in frequency will change the pitch of the buzzer.

Gold

  • Upload photos of the front and back of your project.
  • Your solder joints are good, some dry joints or excess solder.
  • You component placement is good, a few of the components are off the board and not aligned correctly.

Platinum

  • Upload pictures of your completed project here, if you have completed the project to a very high standard.
  • No dry joints.
  • No excess solder.
  • Components legs have been trimed well.
  • The components have been placed on the board neatly.