I need to count how many times a sump pump runs in a given period. The sump pump pumps water out of a hole on the ground, it is activated by a float switch - so generally speaking it pumps the same amount of water out each time it runs (the volume of water from the top 'on' level to the lower 'off' level). I want to know how much water is being pumped per week/month/whatever. [more inside]
posted by Xhris on Sep 15, 2009 - 13 answers

Security alarm: I'm looking for a portable, battery operated house/office alarm system which can watch the only entrance of a flat. It's a concrete building and the front door is the only way in, unless somebody scales a balcony which would definitely be noticed. This should function much like a car alarm, with a remote key fob to arm and disarm, motion sensor and a opening sensor on the door, and make a very loud noise if it's disturbed. [more inside]
posted by thewalrus on Jul 11, 2009 - 4 answers

How to rig up a foosball table to measure velocity of goals? [more inside]
posted by mikeyk on Jun 15, 2009 - 9 answers

How do I rig a motion-activated alert for my office door? Or just stop being startled when people walk in? [more inside]
posted by teleri025 on May 6, 2009 - 15 answers

interpreting a wave from sensor data - what to do about maxed out sensors that are clipping the wave - an absurdly complex question [more inside]
posted by compound eye on Mar 11, 2009 - 13 answers

I'm looking USB heartrate monitor [more inside]
posted by cccorlew on Feb 2, 2009 - 3 answers

How do I replace the evaporative emission system sensor in a Nissan Sentra? [more inside]
posted by quin on Nov 5, 2008 - 1 answer

Can you show me a photo beam sensor or a magnetic sensor that is close to the size of my pinky? [more inside]
posted by kaozity on Dec 3, 2007 - 8 answers

I'm looking for a simple, small and cheap way of measuring acceleration. Basically, I want to make a set of LEDs light up if they are accelerated significantly, becoming brighter the faster the acceleration happens. [more inside]
posted by Zarkonnen on Nov 13, 2007 - 13 answers

I'm completely baffled by Nikon's DSLR strategy and I'd like to understand a few things better: first they create the DX line and seem to indicate that cropped is there to stay, now they go full frame. What should a serious film photographer who wants to go DSLR and already owns a bunch of excellent manual focus Nikon lenses do now? I also find baffling that they're not teling who manufactures their full-frame sensors -- don't potential customers have the right to know who makes the heart of the really expensive camera they may buy? Thanks.
posted by matteo on Aug 29, 2007 - 23 answers

I am looking for a temperature indicator that comes in the form of a sheet, or a film, and permanently changes color in areas that have been exposed to high temperature. Does anyone know where I could find such a device? [more inside]
posted by nickerbocker on Jul 9, 2007 - 6 answers

Why do point-and-shoot digital cameras have such small sensors? [more inside]
posted by bjrubble on Mar 13, 2007 - 21 answers

What is this handheld "force sensor" Jamie Hyneman yields in the "concrete glider" episode of Mythbusters? [more inside]
posted by bluefrog on Dec 13, 2006 - 10 answers

Are there any good tools out there for analyzing binary sensor data? I would like to create something like a timeline of data. [more inside]
posted by b1tr0t on Apr 24, 2006 - 7 answers

The temperature sensor on my motherboard is going haywire! With an ambient temperature of around 30° Celsius, Motherboard Monitor is telling me that case temperature is fluctuating between -50°C and 50°C, with CPU temperature fluctuating between -125°C and 110°C. The sensor is obviously fried, but what can I do about it? [more inside]
posted by Tawita on Jan 7, 2006 - 3 answers

What's a reasonable price to pay to replace a speed sensor in a 1995 Honda Odyssey van?
posted by wsg on Dec 7, 2005 - 6 answers

Our dog stays at home while we're out working. She does fine and has people walking her on most days, but with the generally unreliable nature of electric power on hot Virginia days, I worry that the house may lose power and heat up to an uncomfortable temperature while my wife and I are at work. Does anyone have any experience with an inexpensive, easy-to-setup way for me to get an e-mail alert if the power goes out or the temperature gets to a certain point? This looks neat, but if the house loses power it won't do me much good.
posted by laze on Jul 26, 2005 - 17 answers

Has anyone successfully cleaned dust off of a digital SLR's sensor on their own? [more inside]
posted by almostbarefoot on Jul 19, 2005 - 10 answers

[CarTalkFilter] '94 Buick with electronic heat & a/c controls. External temperature reads 94 degrees F (it's currently around 10 above). What do I check out to fix this? [more inside] [more inside]
posted by AstroGuy on Jan 15, 2005 - 2 answers

Sensorfilter: my digital camera's media card door sensor thinks it's open, even when it's closed. Has anyone ever disabled one of these things? The door stays closed just fine, just the camera doesn't think so.
posted by britain on Aug 12, 2004 - 3 answers