Thursday, April 29, 2010

More *duinos

Two new Arduino-compatible boards are out and are now listed in my big spreadsheet of boards.

The ArduPilot Mega by SparkFun ($60) is an extension of the original ArduPilot, but as its name implies, now sports an ATmega1280 as its main processor. Designed to be the brains behind a UAV or radio-controlled flying vehicle, it's all ready to hook up to a GPS receiver, servos, RC I/O, accelerometers and gyros, etc. It's amazing how much is packed in there-- it even has a secondary ATmega328 and multiplexer.

From Spikenzie Labs, the folks who make the Voice Shield and Altoids tin-sized Prototino comes a "SIP" (Single In-line Package) Arduino-compatible board "Sippino" ($16 kit). It can be mounted vertically or horizontally in a breadboard and has a 6-pin FTDI breakout header for programming, though no power regulation or reset.

Thursday, April 15, 2010

Canon IR Remote Control

After striking out at the Electronics Flea Market Saturday, I stopped at Fry's for a fresh pair of clippers and soldering tips, and picked up a small case too-- a Serpac M4. I used some free protoboard Laen sent me (THANKS!) to build a simple Arduino-compatible circuit to fit inside it, with a single button and IR LED, powered by three LR44 (AG13, 357, etc.) button cell batteries; basically a mutetater circuit with one LED instead of four.

Following Martin Koch's code example, I got the circuit to trigger my 350D's shutter, making it functionally equivalent to a Canon RC-5 remote control. Using an ATmega168 is overkill though: most pins go unused, and it nearly drained the three LR44 batteries when left on all night.

I figured putting it to sleep would solve the power consumption problem, so I modified the ArduinoSleepCode example from the Arduino Playground to make the D2 button both wake it up from sleep and trigger the shutter. It doesn't need to be awake for any time at all really before going into "SLEEP_MODE_PWR_DOWN": the wake up function triggers a shutter release event; currently it sleeps after five seconds. This will be a key feature of the mutetater and a more complete intervalometer-- using a button or a DS1337 clock alarm to wake up when needed.


Thursday, April 8, 2010

Minimalduino v.89 Delivered

Three copies of my latest Minimalduino design (V .89) arrived today, fabricated in the DorkbotPDX circuit board order. I built one with all components and it works perfectly, with the exception of the 3.3V regulator having a different pinout than the 75LXX part I used in Eagle-- oops...

A SparkFun protoshield and Adafruit motor shield fit on top fine, but with very little (read: "zero") clearance over the tall capacitors I used-- they'll get some tape on top, and the next revision will use shorter caps or orient them sideways. Excited to work with my first factory-made board, I shot and posted some build pictures with a few notes.

To correct in the next revision:
  • Fix 3.3V regulator (MCP1700-330) pinout,
  • Lay out for wider/shorter or horizontal voltage regulator caps for better shield vertical clearance.
To add/improve in the next revision:
  • 5V/3.3V switchable with a jumper on three pins (though it will limit power),
  • Top pad and through holes under 7805 for better heat dissipation,
  • Credits (CC, author names) on bottom silk screen,
  • Optional resettable fuse?
  • Optional on/off switch or jumper pins?
  • Try to reduce the number and length of jumpers.