Interactive Megaphone: Tutorial

About This Project

This is a tutorial about making your own interactive megaphones.


  1. Download and print on a 1:1 scale the PDF drawing attached here  Megaphone_medium_size_A1. Print on thick A1 size paper or print on normal paper and then draw the outline and inside dotted lines on corrugated cardboard sheets. We recommend using a 1.5mm thick E-Flute corrugated cardboard sheet.
  2. Make a nice cutout with scissors or cutters. Younger people need to be accompanied during this or the educators need to prepare the cutouts before the workshop.


  1. Use Bare Conductive paint to paint your words/message on cardboard with stamps or thick paintbrushes.  Do not dilute the paint, instead use a good amount for each letter but not too much in order to shorten the drying time and to make the sensors functional (too much paint will reduce conductivity).
  2. Stamps tend to create uniform, legible letters. Find attached an A3 size sheet you can use to cut out your own letters or have them cut on a router-cutter.
  3. Make sure that letters connect on one side if you want all parts of the word to form a single sensor. Remember electricity needs to go across a continuous conductive surface! If letters do not connect it is like cutting a cable in two.
  4. Allow 15 minutes for drying.


  1. Fold towards the inside the flaps. Pass the flaps one by one (starting from the side that connects to the top and bottom opening) through the openings of the holes like on the images attached below.
  2. The megaphone is ready.


  1. To record your messages use Audacity on a computer. You need to export sounds as .mp3 in order to upload on the Touchboard. Audacity does not support mp3 encoding so you need to download and install the LAME plug-in and follow the installing instructions here.
  2. Once the LAME plug-in is installed you can open a New File on Audacity, hit the Record button to record your messages, the stop button when done and then File > Export Audio > MP3 Files. Name your tracks starting from TRACK000, TRACK001… because the microSD card on the Touch Board reads them in that order and naming.
  3. Now plug in your Touch Board. You will need a power supply, either a Li-po 3.7V battery and a micro-USB cable to charge it, or just a micro-USB cable if you keep your Touch Board connected to you laptop after the workshop.
  4. You will need to buy a micro-SD card and Reader and plug it in your laptop. Copy and paste your audio tracks inside the folder TBAUDIO with the numbering TRACK000, TRACK001, etc. You can upload many tracks but with our Arduino sketch you can up to tweleve (12). Place your micro SD card back on the Touch Board and connect the Touch Board via USB to your computer.
  5. You need to have installed the Arduino environment on your laptop.
  6. Open the Arduino folder Touch_MP3_play_when_stopped and open the sketch inside the Arduino environment. Connect the Touch Board and upload the sketch at baud 57600.
  7. When you touch the 12 nodes on the Touch Board now you should be able to hear the recorded messages.
  8. Use crocodile clips to connect the sensors (words) with the 12 nodes on the Touch Board.
  9. For troubleshooting the Touch Board please check the official tutorial here:


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