Making a Space Invaders Synthesizer #ArcadeGames #SpaceInvaders #Vintage @Make

Via Make, Charles Platt writes about the SN76477 chip which turns 40 years old. Made by Texas Instruments, the chip was marketed for sound effects in arcade games, including the classic Space Invaders.

Just send high or low signals from an Arduino or any other 5V microcontroller, and you can sequence a cacophony of rifle shots, sirens, the puffing of a steam locomotive, and a sentimental lullaby. Better still, all of the sounds will share that retro arcade ambience.

Apply a 9V battery, and the chip contains its own voltage regulator which converts the power to 5V internally and also makes it available (up to 10mA) from a 5V output. This you can use to power the logic inputs.

Sound from the chip has to be amplified, and the manufacturer recommends (on the datasheet) using a couple of transistors. I found that a single 2N3904 would work.

Platt shows that you can hook the chip up to discrete components to make a synthesizer.

Despite the age and obsolescence of the SN76477, you can still buy samples from multiple eBay suppliers for around $15.

So now if you’ve been putting off the chore of synthesizing the sound of a crashing car while an electronic organ plays “Twinkle, Twinkle, Little Star,” you have no further excuses. The SN76477 can do it all.

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