Author Archives: Jim

Cupric Chloride is Green!

Posted on April 20, 2011 by Jim

Wow – after an extra couple of days’ aeration (with extra acid during that time), the etch bath is beautiful light green in the drop-on-white test.  It’s ready to go!  I’m really curious whether the acid had any effect on … Continue reading →

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Educube Performance Update

Posted on April 19, 2011 by Jim

After digging into I²C protocol some more I felt armed to hack the MultiSerial library to do multi-byte reads and writes.  I added 2 user level functions – writeMulti() and readBuf().  I had to add 2 more internal functions – … Continue reading →

Posted in W88 Educubes | 4 Comments

Cupric Chloride Etchant Getting Closer

Posted on April 19, 2011 by Jim

When I looked at the jar on 4/17/11, it was just kind of ugly brown, even though it had been on the bubbler for days.  I started to look a little closer, making measurements and doing a little math.  So … Continue reading →

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Cupric Chloride update

Posted on April 18, 2011 by Jim

I had to do the last 4  IR boards for the Educubes last night, and hoped the CuCl2 etchant might be ready.  It wasn’t – so I used ammonium persulfate again. Most of the 80g of wire dissolved over the … Continue reading →

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A Rude Awakening on Educube Comms Performance

Posted on April 15, 2011 by Jim

I was frustrated because message transport between cube bases was slow/erratic.  At 115200 b/sec, the best case is ~11KB/sec.  For a 22 byte message, that’s 2 ms best case.  That’s a pretty short in timelines measured in 10s of ms.  … Continue reading →

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Educube IR Board update

Posted on April 15, 2011 by Jim

I’m almost done with what I’d hoped to do!  I just finished soldering up the last of the five boards.  I only have four Diavolinos, so I tested the last one by hooking it up to a regular Arduino.  All … Continue reading →

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Cupric Chloride Etchant – Update

Posted on April 15, 2011 by Jim

I had to go back to Ammonium Persulfate for the last of the Educube IR boards.  Etching was slow to very slow with the CuCl2 and results were poor.  There was substantial undercutting of traces around the edges.  That was … Continue reading →

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Cheapie USB-TTL Adapters

Posted on April 15, 2011 by Jim

Thinking there might be need for some more “FDTI cables” – USB-TTL serial adapters with a 6 pin 0.1″ female header to plug into USB-less Arduino clones (like our Diavolinos), and being offended at the pretty standard $15 pricetag of … Continue reading →

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My Cupric Chloride Etchant Experiment

Posted on April 12, 2011 by Jim

Encouraged by promise of not having to dispose of etchant bearing environmentally harmful copper salts, I decided to try the great green cupric chloride etchant.  I started my batch with 8 oz 31% HCl and 4 oz of 3% H2O2.  … Continue reading →

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W88 Educube IR board

Posted on April 10, 2011 by Jim

I’m well into the prototype stage of 2-channel IrDA IR comms Arduino shield for the Workshop 88 Educubes GGHC project. Very efficiently, IrDA uses very short (~10μs) IR pulses, which must be delivered by the UART driving the IR transmitter.  … Continue reading →

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