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The kit's clear hinged case, closed, seen from above. A lime green label on the lid reads Onion Madder's, Breadboard Kit, Opto Duet, messopedals.com, beside a black outlined heart with a pulse line through it. Through the plastic are the folded bench guide, the orange packet of the breadboard and a corner of the power module.

Breadboard kit · Two 555s chained by light

Opto Duet

DIY Kit

A two-voice light-controlled noise box. One 555 sets the tempo, the other makes the tone, and a sealed LED-and-photocell pair chains them so the tempo half plays the pitch half.

  • Buildsthe Opto Duet guide, free to read first
  • BoardMB-102 solderless breadboard
  • Power9V battery into the breadboard power module, both in the box
  • SolderingOnly the four leads of the home-made vactrol, before you start on the board
  • InstructionsA printed bench guide: the parts, the exact holes and how to power it up
  • PartsAll brand new

Breadboard Kit

Solderless. The parts push in and pull back out, so you can build it, take it apart and build the next one on the same board. The off-board parts come with wires soldered on and the ends crimped to push into the breadboard.

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Parts Only, Wired

Every component for this build and the printed bench guide, with no board, case, power module or battery. The off-board parts come wired and crimped for a breadboard. For refilling a breadboard you already have.

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Parts Only, Unwired

The same parts and bench guide, with the off-board parts loose for you to wire. For your own breadboard, solderable or not.

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Want to solder it and keep it? There is a permanent kit of this build.

What is in the box

  • every component for the Opto Duet, bagged and labeled
  • the off-board parts with wires soldered on and the ends crimped for the breadboard
  • a full-size MB-102 solderless breadboard
  • the breadboard power module
  • a 9V battery and its connector
  • jumper cables
  • the printed bench guide for this build
  • the hinged case it all lives in, with its label on the lid

A parts-only pack is the components and the printed bench guide, and nothing else: no board, case, power module or battery. Pick wired if you want the off-board parts ready to push into a breadboard, or unwired to wire them yourself.

Read the build first

The whole build is free on the Opto Duet guide: the parts list, every hole, how it works, the mods and the troubleshooting table. The bench guide in the box is the short version for the bench, with a QR code back to the full one. If you already have the parts, you do not need the kit.