OKAY 2 Monophonic Synth Kit

 writes on the Tindie blog:

okay2-Medium

OKAY 2 Monophonic Synth Kit

Take a look at Tindie’s thriving sound section and you’ll see there is no shortage of people making their own electronic music. These devices take many forms, and one interesting take on sound creation is the OKAY 2 Synth DIY Kit. At face value it features 2 octaves of keys, a built-in amplifier along with a 1/4″ line out, and knobs to select the octaves that you’d like to play — but it gets more interesting under the hood.

Oskitone OKAY 2 from oskitone on Vimeo.

What makes it unique by today’s standards is that it doesn’t use any sort of computer or microcontroller, but instead produces sound using an LM555 timer along with other discreet components for monophonic sound. Given its small size, you could use two at once, perhaps combining them via the line out to be further modified in your synth setup!

In case you’re wondering, the original—or nearly so as it’s version 1.1.1—OKAY is also available. It works largely the same as the OKAY 2, but features only a single octave of keys, and doesn’t have an audio output jack.

OKAY 2 Monophonic Synth Kit

555 Piano

Alexander Ryzhkov created a small 555 timer-based piano:

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555 piano

Main goal of this project has been creating pretty designed 555 based piano in small form-factor. Many 555 piano are using 9V battery for supply. I use CMOS timer and for timer need only 3V supply.
The design files are available on GitHub:

githubChirnoTech/555Piano

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Here is a video of the board in action:
openidev has shared the board on OSH Park:

piano.toplayer.zip

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Order from OSH Park

555 Piano

Brake Lamp Flasher for Motorcycle

Bryan Cockfield of Hackaday writes:

Brake Light Blinker Does It with Three Fives

Sometimes you use a Raspberry Pi when you really could have gotten by with an Arudino. Sometimes you use an Arduino when maybe an ATtiny45 would have been better. And sometimes, like [Bill]’s motorcycle tail light project, you use exactly the right tool for the job: a 555 timer.

boardsMore details on William F. Dudley’s project page:

Brake Lamp Flasher for Motorcycle

The 555 is a clever chip; not only will it supply the oscillator for the flashing effect, it has a reset pin that can be used to force the output to a known state (low) when (other circuitry tells it that) it’s time to stop flashing. Thus the brake light will be steady “on” after a few flashes every time the brake is applied.

brake_blinker_1_schem

The 555 is happy to run directly off the nominal 12 volt vehicle electrical system, so no voltage regulator is needed. The 555 is almost immune to electrical system noise, so no worries about your Arduino code going off into the weeds if there’s a spike from the electrical system.

 

Brake Lamp Flasher for Motorcycle