Kevin Warnock

Jeff Clavier, left, August 30, 2012, at Berkeley Entrepreneurs Forum at University of California Berkeley

I have learned that smoke and fire detectors almost always signal low battery condition in the early morning between midnight and five o’clock. This wakes me up and forces me to replace batteries when I am sleepy. I suspect many people don’t have spare batteries always on hand like I do, and simply take the batteries out until they can go to the store. This leaves the premises less well protected, and I suspect fires have started during this period and that people have died.

The fix is so simple I can’t believe I only thought of it today.

Simply include a clock in all battery operated smoke, fire and carbon monoxide detectors. Have this clock powered by its own battery that can last a decade or more. Set this clock at the factory for the part of the world where the detectors will be sold. The low battery circuitry should consult this on board clock, and should suppress the chirping ‘low battery’ notification during typical sleeping hours, say from 10pm to 8am. The chirping can resume at 8am each day until the batteries are replaced. Alarms typically will chirp for months before they run out of power entirely, so the delay in chirping during the night will not cause a significant safety issue.

The clock should be user resettable so the detector can be moved between time zones by the buyer, or set to accommodate unusual sleep schedules.

I suspect the clock I am proposing costs no more than USD $.50 in bulk, and the feature that it will enable can be promoted to boost sales. I suspect such a detector will sell well because I suspect everyone with a detector has been awakened by their chirping.

Chirping during waking hours is likely to be a measurable advance in fire and poisoning safety, since awake and alert people are less likely to make mistakes, like removing the batteries or putting in replacement batteries backwards.

Jeff Clavier's Facebook Wall as of March 22, 2013

While the circuit designers are at it, they should program the detectors to keep track of the passing years and notify the user when the detector has reached its end of life, around ten years after manufacture. I am sure there are millions of ‘expired’ detectors still in use because people forget when to replace them.

This is my second post on how to improve detectors. My first post Smoke detectors should send activation warnings via text messages via Wi-Fi I wrote July 23, 2011.

I believe detectors chirp now early in the morning because batteries deliver less power when cold, and in many homes the temperature drops lowest early in the morning. Here’s a post by The San Diego Real Estate Inspection Company that agrees with me.

Thank you to SoftTech VC venture capitalist Jeff Clavier for sparking my imagination today to think up this fix. Clavier asked on Facebook this morning why detectors report low batteries exclusively at 3:30am. It’s then that I thought of including an internal clock to solve the problem. I posted my suggestion in a comment on Clavier’s Facebook Wall, and then decided to write this post to formalize my suggestion, with the hope the idea gets discovered and implemented.

If this idea makes money for you or your company, please send me an industry average royalty for using this, out of the goodness of your heart. I am guessing that will amount to about USD $.05 per detector, but that could result in my getting ever more wealthy over time given every residence on Earth should have multiple detectors forever. Thank you!

I will not patent this so it’s now in the public domain if it hasn’t already been patented, which is not unlikely given how simple the idea is. I could quickly find no mention of this idea after performing a Google search for this idea.

I wrote about Jeff Clavier last year, and I took the picture of him that accompanies this post. Clavier speaks colorfully. My favorite quote from when I saw him speak August 30, 2012?

“I passed on airbnb that some showed me when it was called air bed and breakfast and I said ‘air bed and breakfast… are you f—ing kidding me?”

My preference is that the world move quickly towards hard wired sealed detectors that have backup batteries that will last ten years. It also seems that non hard wired detectors should have solar cells like calculators and watches, to keep the batteries from having to drain themselves so quickly.

My clock idea I present here is still relevant to such detectors, since I would prefer to learn the detector needs replacing while I am awake and likely to buy a new one at once.