Showing posts with label valves. Show all posts
Showing posts with label valves. Show all posts

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.

Sunday, July 19, 2009

PPAC Progress: UP!

I've been working on (mostly) minor tweaks to the alarm clock:
  • The can I had used to test mounting techniques served its purpose as a prototype, so I redid the mounting in a fresh can, with adjusted positioning of the LCD and (new) lit button, with use three screws per end cap instead of two. I scanned the LeSueur label and printed a copy to test the positioning of the LCD, button, and power/relay port cutouts.
  • I over-tightened the plastic ring which opens the output valve of my 10-gallon air tank, leaving me with a sealed can at 105psi! I bought a 5-gallon tank as a replacement, figuring it would be fine for a full run, and was impressed by its lightness. I "fixed" the 10-gallon tank's valve by cutting off the plastic ring, so I can turn the open/close with a small wrench, so now have 15 gallons to pressurize.
  • Testing the 5-gallon tank at 100psi, the plastic "open" safety valve popped a leak, so today I replaced all pre-solenoid valve hardware with brass-- no more leak!
  • Since the emptying valve didn't get enough pressure from the inflated "pea" to open, I replaced it with a manual valve-- not as elegant, but the alarm is about inflation, not deflation.
  • The alarm was still triggering when the alarm was "off" and the target time was reached, plus there were a few small bugs to work out.
  • The maximum inflation time was set arbitrarily at 30s, so I added another click+hold "hidden" mode branched from the alarm mode selection so the max inflate time can be adjusted. It's also stored to (Arduino) EEPROM with other "system" parameters.
The IDE tells me I still have a little headroom:
"Binary sketch size: 13566 bytes (of a 14336 byte maximum)"
I'm tweaking the program a but more, but it's late and I'm so happy with how far it has come! I plan to be woken up rudely in the morning...:D