µC generates musical sounds:  04/15/99 EDN-Design Ideas / (added 6/06) [Note:  File contains multiple circuits.  Scroll to find this one]  Many modern devices send audible signals to IR operators to indicate some of predetermined conditions or states of system under control. To avoid annoying human sensibilities, se sounds should match musical scale. Several chips on market provide such sound capabilities; for example, a programmable sound generator or an ISD1016 voice massager.  Circuit in Figure 1 does not use a dedicated sound generator but rar generates sounds using software routines.  Circuit uses an inexpensive MC68H705J1A µC and saves additional expense by eliminating need for a sound chip. In Figure 2a, a note represents pitch of each musical tone; Figure 2b shows duration of tone....

10 to one voltage divider for direct input:  Very simple DI-box idea for your guitar amp output... (circuit design added 10/06)

100 Watt Guitar Amplifier #2:  (electronic circuit added 4/05)

100 Watt Guitar Amplifier Mk2:  (circuit design added 3/05)

10W Audio Amplifier with Bass-boost:  High Quality, very simple design No need for a preamplifier  (added 4/05)

25-Pin PC Serial Port to MIDI Synthesizer Interface Cable:  (circuit / schematic design added 2/07)

300W Subwoofer Power Amplifier:  Please note that  specification for this amp has been upgraded, and it is now recommended for continuous high power into 4 Ohms, but You will need to go to extremes with  heatsink (fan cooling is highly recommended). It was originally intended for "light" intermittent duty, suitable for an equalized subwoofer system (for example using  ELF principle see  Project Page for  info on this circuit). Where continuous high power is required, anor 4 output transistors are recommended, wired in  same way as Q9, Q10, Q11 and Q12, and using 0.33 ohm emitter resistors. ... (added 4/05)

5 band graphic equalizer using a single IC/chip:  This circuit uses a single chip, IC BA3812L for realizing a 5 band graphic equalizer for use in hi-fi audio systems. BA3812L is a five-point graphic equalizer that has all  required functions integrated onto one IC.  IC is comprised of  five tone control circuits and input and output buffer amplifiers.  BA3812L features low distortion, low noise, and wide dynamic range, and is an ideal choice for Hi-Fi stereo applications. It also has a wide operating voltage range (3.5V to 16V), which means that it can be adapted for use with most types of stereo equipment.
 five center frequencies are independently set using external capacitors, and as …. (added 10/05)

60W Bass Amplifier:  Low-cut and Bass controls.  Output power: 40W on 8 Ohm and 60W on 4 Ohm loads (added 3/05)

60W Guitar Amplifier:  Bass, Treble, Harmonic modifier and Brightness controls.  Output power: 40W on 8 Ohm and 60W on 4 Ohm loads (added 3/05)

8 Note Tune Player:  Circuit plays 8 note tunes at any speed (added 5/02)

9-Pin PC Serial Port to MIDI Synthesizer Interface Cable:  (circuit / schematic design added 6/06)

Add harmony to your system:  07)/20/00 EDN-Design Ideas / (added11/05) Have you ever wished you could distinguish one device's operating state from anor's by  sounds y make or that error states would sound harsh while normal operations would sound harmonious? By combining  NCO technique from a previous Design Idea (Reference 1) with digital mixing, you can obtain musical chords or intervals with a minimal amount of hardware and software. Any µC system can thus produce a variety of sounds. In Figure 1, a piezoelectric speaker, Radio Shack Model 273-091, and two 270W resistors transduce a pulse stream from a µC. Differential drive to this transducer increases  volume by doubling  effective voltage. The capacitance of  piezoelectric speaker reacts with  270W resistors....

Add music to your next project:  12/23/99 EDN-Design Ideas / (added 3/03)

Apple Mac to MIDI synthesizer interface cable:  (electronic circuit added 2/07)

Apple Macintosh MIDI interface schematic (basic version):  (electronic circuit added 2/07)

Apple Macintosh MIDI interface schematic (deluxe version):  (diagram added 2/07)