Saturday, November 28, 2009

Minimal Arduino?

I prefer breadboard-friendly Arduino-compatible boards like Boarduino and iDuino, but I keep wanting functionality people have built into shields like Adafruit's Motor Shield and Batsocks' TellyMate Shield.

All I want in an Arduino:
  • ATmega328
  • FTDI programming header
  • Arduino "form factor" with odd D7/D8 spacing and standoff holes
Sorting my Arduino-compatible board spreadsheet first by price, then by form factor, it seems the lowest price for a shield-compatible board is ~$17 for a serial Freeduino, compared to ~$10 for a Dorkboard, though the latter comes with an ATmega168, not a 328.

Necessary items:
  • microcontroller: ATmega328, socket, capacitor
  • clock: oscillator and 2 caps, or a resonator
  • reset: 90-degree (side) button, 10K resistor
  • FTDI cable interface: 6-pin header, capacitor
  • Power: Barrel connector, 2-pin header
Extra interface header pin pads:
  • icsp (2x3)
  • i2c (4)
  • spi (6) (nah)
Simple extras, parts not provided:
  • Power indicator: LED, 1K resistor
  • TX/RX indicators: 2 more LEDs, 2 more 1K resistors
  • Power regulation: 7805, 2 capacitors, jumper
  • Diode to prevent inverted power hookup
I'm traveling for the next month so this will be a fun little layout project, perhaps as a way to learn kicad (as opposed to EAGLE, which I currently use) and to explore board house pricing and specs. The goal is to be able to produce a $10 kit (cost), which may be possible given how many goodies SparkFun includes in their $20 Arduino Pro 328.

Update 12/29: I got a single-sided board laid out with just four jumpers, and I'll tear it up and redo it with the programming header where I want it, jumping TX and RX across the board. The files for the "Severino" single-sided board helped me figure out the routing.

Wednesday, November 18, 2009

PPAC Demo Video

The inflation feature demonstrated with the bed unoccupied:

(Sorry for removing the original video, but... I promised Liz I'd remove it!)

Tuesday, November 17, 2009

Getting Out Of Bed: PPAC Major Components

The "Princess and the Pea Alarm Clock" (PPAC) has been working beautifully, waking me up with "buzz" alarms and literally getting me out of bed with "inflate" alarm functions! I will post more photos and videos soon, but first to outline the alarm clock's major components:
  • Alarm clock: LeSueur peas tin can containing the main circuit board, jog/shuttle dial and button input, 16x2 character LCD display, modular handset cord jack, and female 6-pin FTDI cable jack.
  • Power block: Power input/output circuit mounted in a plastic iPod Nano box, with input DC power jack and regulator, relay input power jack, two relay-switched output jacks, modular handset cord jack, status LEDs, and main power switch.
  • Valve tree: Brass and plastic fittings around the main trigger solenoid-controlled sprinkler valve, with quick-release fittings on both ends, manual safety valve before the trigger valve, and manual release valve.
  • Air pressure source: 10-gallon (red) or 5-gallon (yellow) air tanks, both with pressure gauges and female quick-release connectors, usually filled to 110-120psi.
  • Air bladder, aka "Pea": Green exercise ball between my mattress and box spring, with a hose ending in a male quick release fitting.

Monday, November 16, 2009

Silly Alarm Clocks

I've been bookmarking funny alarm clocks for a while-- snoozing is so universal, and I get a kick out of the features people choose to include in their wake-up devices to ensure that they actually get out of bed. While not Arduino- or ATmega-based, here are a few of my favorites:
  • Clocky news popped early 2007, and it took me about a minute to place an order-- had to have one as soon as possible! It was too easy to just turn on its side, though, with the side of a tire as the base, so it spins around on my night stand instead of taking off. Cones on the end might prevent that, but I still love it, and it got me thinking seriously about my old inflating alarm clock idea, so is probably the single biggest inspiration for the PPAC.
  • The Pneumatic Bed Shaking Alarm Clock was built for Toronto's "The Edge" 102.1 "World's Biggest" contest and while it seems too violent to be used every day, its maker claims to have used it to get up for four years! This may be the epitome of taking a silly alarm clock idea too far, and I have nothing but the utmost respect for its maker.
  • The Perfect Wake-up Machine, a design project by students a Colorado State University, assaults all senses with its control of just about anything. Serial communication, a few PIC chips, and multiple power systems combine to make a beast of an alarm clock-- kudos for overkill!
  • "The World's Loudest Alarm Clock was a simple but effective build by Kip Kedersha (aka "Kipkay"), replacing a cheap alarm clock's speaker with two sirens for a deafening wake-up experience. Like The World's Biggest Alarm Clock, I can't see this as something anybody would want to use a second time!
  • Alarm Clock/Bedpost "-MAWD-" is an odd refitting of an alarm clock, lamp, and speaker into a tube attached to a bedpost. Most notable for being the product of a one-night, I'll-do-it-right-now!-inspired fit of tinkering, it has "silly hacker" written all over it. I love the tangle of wires supporting the LCD.