Category Archives: Uncategorized

Successful drive test

Accelerates and decelerates. Backs up and turns around.

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New wheels

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Actually, these are reused from my first CNC project, which lies behind a pile of junk in the garage. With a locking washer, I was able to mount these to the bot.

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2015-04-25 · 23:49

New display

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Brighter and easier to read while moving, the new display shows status information at a glance.

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2015-04-25 · 00:40

Whisker demo

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2015-04-09 · 01:49

EE40LX: two sensor bridges with power blocking

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Two photo sensors with bridge and comparator front ends. Power supplied by a MCU pin, which switches high only when measurement is needed. This reduces overall power consumption, which is 11.355mW for both bridges.

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Filed under analog, edX, ICs, micro-controllers, Robots, Uncategorized

Holiday ornament: Update 1

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As of the wee hours this morning, my remix of the board layout is finished, and has been queued for fabrication in China by the no-nonsense folks at DirtyPCBs.com.
More updates (code & schematic) will be posted shortly.

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Holiday ornament design

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After scouring the dangerous prototypes google code repository this past spring, I stumbled upon a novel design for a hackable holiday ornament, with glowing SMD LEDs as lights strung on a tree. Clever use of exposed vias and silkscreen printing created a festive effect of glittering decorations and an ATtiny13A wrapped up as a gift underneath the tree. At that moment I decided I needed to build on this design and hopefully have something nice to give as a gift this season.

The original design had only one NPN transistor switching 10 0805 chip LEDs. My original plan was to replace the transistor with a 74HC595 shift register, but the tiny13’s 1K of flash space proved too small for my mediocre coding ability. Thus, I simplified to 5 discrete transistors switching the 10 LEDs in groups of 2. I modified Ian’s original design to drive a PWM on 5 pins using an interrupt on the tiny13’s timer.

Presently working to adapt the board layout. Adding the extra passives and NPNs has made for a busy front, so I’ve moved them (mostly) to the back. Working against the clock the design done in time to have my boards from DirtyPCBs before Christmas, so there are no URLs or references in this post. They’ll be added later.

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