Audio Fade-In And Fade-Out - Maker Factory ELECTRONICS EXPERIMENTS BOX Manual

2.85 Audio Fade-in and Fade-out

Circuit 183: Audio Fade-in and Fade-out
Setup information
Install the transistor, the diode, the five resistors and the three electrolytic capacitors as shown in Fig. 2.183
Insert the eight jumpers. A jumper wire with only one end inserted serves as the "switch". For your guid-
ance it is shown dashed and labelled with Fade in/Fade out. Last but not least connect the Piezo element.
Check the placement on the board again and only then connect the battery.
You can significantly increase the sensitivity of the Piezo element by using a sound plate or even a sound
box. Read more about it in Chap. 1.2.3
Experiment
Automatic fade-in/fade-out is a feature of all PC audio editors. Here we have a hardware solution for this
functionality. Connect an mp3 player to the input and listen to the music blasting from the Piezo element. If
the "switch" is closed, the volume drops continuously back to zero within a second. If the switch is opened
again, it takes a second to turn up the volume continuously until it reaches the maximum.
The circuit diagram for this experiment is shown in Chap. 3, Fig. 3.183.
208
Components required:
1 x J111 FET transistor,
1 x 1N4148 silicon diode,
2 x 22 kΩ resistors,
2 x 220 kΩ resistors,
1 x 1 MΩ resistor,
1 x 1 μF electrolytic
capacitor, 2 x 10 μF
electrolytic capaci-
tors, 1 x Piezo element,
1 x breadboard, 1 x 9V
battery with clip con-
nector
Fig. 2.183: Audio Fade-in and
Fade-out