Coffee Control

It looks like we'll have remote control of the grinder timer by the end of the week, along with power for Mr. Coffee and the Gaggia Classic!

The first step (mentioned in my previous post) was to get my old (V1.0) Adafruit Ethernet Shield up and running with an XPort Direct+ and the color picker sketch on the examples page. Then I stripped down the sketch, reconfiguring it for general pin control: toggle outputs, set PWM output values, pulse, and read analog values. After that, I simplified it for the coffee control project which only needs three digital output pins.

One obstacle was getting my LAN to the kitchen counter, and an old AirPort Extreme from my scrap bin (found on the street!) did the trick: it now wirelessly bridges our home network via WDS and connects to the ethernet shield with a cable, its USB port powering my minimal Arduino-compatible board underneath with enough 5V power to spare for Mr. Coffee's relay; I'll add a 12V source for a bigger, higher power relay to switch the Gaggia Classic.

The Arduino side of the system works great, serving a web form (at right) to turn the two power relays on or off and to trigger the grinder timer. The last part is always the hardest, though: wiring and casing it all up. Safe wiring will take some time to nail down, with Mr. Coffee needing ~1025W and the Gaggia Classic rated at 1370W (!). As for the case itself, lucky for me some folks from Ponoko are scheduled to make a presentation tomorrow (er, later today ;) at the Make:SF Meetup-- just the info I need, right when I need it!

PPAC Fixes, Minimalduino, Timer

I've been busy lately and haven't had as much time as I'd like to tinker, but I've gotten things moving in the last two weeks and am overdue to post.

Hoping to show off the alarm clock a little, I brought the PPAC (including power block, valve tree, and tank) to the Make:SF Meetup last month, and while talking and hooking it up at the same time, plugged the AC supply into the DC power socket! The voltage regulator fizzled but the power board seems fine otherwise. Strangely, of all things, the LCD display was dead as well... though I may have killed it when disassembling the can..:o I ordered a better looking LCD replacement which I'll install in the next few days-- green-on-black instead of black-on-green: Newhaven NHD-0216K1Z-NSPG-FBW-L.

The minimalduino project is still moving forward: I'm using a test board I made at home a few weeks ago, populated with as little as possible: chip, caps, resonator, female headers, reset and male FTDI header. I'll move a few traces around but it's pretty much there, and hope to get three test boards made through the DorkbotPDX PCB order, deadline noon on March 29. I've built a spreadsheet with costs, and it seems like I could make a batch of 25 kits at just under $15 each. I'm not sure if it's worth the trouble though.

A few weeks ago, I built a new coffee grinder timer with a re-worked sketch and single board, then handed it off to fellow coffee fiend HF for ideas on how to make the ideal grinder timer. One thing we agreed on is that tenths of a second would be cool, so last night I had a great time working out a sketch to drive a common anode 3-digit 7-segment display using an SAA1064 IC. Of course having a sketch to start with made things straightforward-- thanks Alessandro Saporetti! I reworked the code to make it more general purpose, using all of the chip's functions including multiplexed (versus not) and changing the constant current output (7 output levels possible, from 3 to 21mA). [Video to come]