[Noisebridge-announce] Instructables Breadboarding Challenge

Johny Radio johnyradio at gmail.com
Thu Sep 12 05:52:12 UTC 2013

There will be free pizza.

WHAT: Instructables/JameCo Breadboarding Challenge
WHEN: Sunday, September 22nd, 4pm to 8pm.
WHERE: Noisebridge
WHO: intermediate and Advanced circuit-makers.

Join us for a breadboarding challenge, sponsored by Instructables.com 
and JameCo Electronics. We've got 4 breadboards, 4 9-volt batteries, 
tons of LED's various colors, buncha resistors, some small LED panels 
who's function i cannot fathom, a bunch of crystal oscillators, some 
weird russian capacitors, and miscellany. Our challenge is to build 
something functional with these parts.

We can pull a few extras we from NB stacks. I'm not permitting 
microprocessors or microcontrollers, but we may use simple digital 
switches, dividers and counters, transistors, and 9volt-to-5volt DC 
converters in NB stocks, if needed for TTL (or fake it with resistor 

Attendees will form themselves into 4 build teams. Each team's board is 
required to provide the following connections to the outside world:

  * One or more LED inputs, for driving LED's. These would be driven by
    rising and falling voltages from other teams' boards.
  * One or more gradually and/or abruptly rising and falling voltages,
    to drive LED's and discharge-switches and other teams' boards.
  * One or more digital switch control-terminals for discharging caps,
    driven by rising and falling voltages from other teams' boards.

Then we can interconnect the boards from each team, and watch the 

Attendees will vote for the winning team. The winning team wins a food 
gift certificate or equivalent prize.

The idea is to drive the LED's with the capacitors, and to charge the 
caps with the outputs of the crystal oscillators, and also to charge the 
caps with each other, by connecting them in random ways. I envision the 
LED'S fading and/or switching on and off in complex patterns, as the 
caps get randomly charged and discharged. We can use digital switches to 
discharge the caps, thus producing control-voltages. And control those 
switches with control-voltages coming from other caps.

So, the key to all of this is the ability to gradually charge one cap, 
or several caps, over the course of a few seconds, driven with the 
output of a crystal oscillator. Please send me suggestions on how we 
might achieve this.

Then, some other (unrelated) control-voltage will discharge the cap, and 
the process starts over.

One idea is to use two or more crystal oscillators of different 
frequencies, and translate the phase difference between them into 
Up/Down voltages (as in a PLL, but without a VCO). Maybe we can achieve 
varying phase differences by switching between different oscillators 
(with digital switches). Or, maybe a mic input could provide a reference 
freq for the phase comparator.

Be there, or be a square-wave.

Johny Radio

Stick It In Your Ear!

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