Gadget Freak Case #112: Simple Pressure Alarm Monitors Water and Air

By Design News Staff -- Design News, November 19, 2007

William Grill had a periodic problem with backed-up water in his laundry room. The laundry tub has a shallow drain that is shared with the kitchen plumbing. The drain would regularly get clogged with refuse from kitchen disposal debris or laundry “goop.” When the drain clogged, water backed up onto the floor, creating a “rather unpleasant laundry room crises.”

Grill considered a water monitor, but he wanted a bit more warning so he could avert flooding. He wanted to know when the drain was getting clogged before “water was all over the place.”

He created a sensor that is set for two points — 1 and 5 inches of water in the laundry tub. The sensor sends an alarm before the water crests the tub and splatters all over the floor — all for less than $12 in components.

Get the Build Instructions | View Parts List | Post a Comment

Amt	Part Description
1	Quad op-amp	735-3649
1	Detector	870-0202
1	100 ohm R Single Turn Pot	754-0840
1	10K ohm R Single Turn Pot	754-0845
1	10K ohm R 1/8W Resistors	296-6224
2	680 ohm R 1/4W Metal Film Resistors	296-0039
2	470K ohm R 1/8W Carbon Resistors	296-6238
2	Diodes	263-1538
1	Regulator	263-0136
1	Power Jack 1.3 mm	932-2202
1	PiezoAlarm	623-2024
1	Black 2.75 x 4.6 Enclosure	278-0571
1	SPST Rt angle Toggle	948-0261
Additional parts required:
1	Sensor
1	Controller
Get the Build Instructions

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the controller code, included in the article text, may not be readable. A text file with this...
- 2008-04-13 15:24:02
Go the next step. Use the upper level to latch off a power relay, shuttin gdwon the washer,...
- 2008-02-04 15:21:11
Schematics would be nice,although the challenge of figureing it out in my head is intrigueing.....
- 2007-11-26 11:18:52

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