When the power goes out at home, what do you do? Most of us probably scramble around the house looking for a flashlight. [Gigawatts] wanted a better solution, so he built an emergency lighting system based off a standard household UPS. A while back he had constructed a relay-switched outlet box to help periodically restart his cable modem which would get hung up a little too often for his liking. Since changing Internet providers, he no longer needed the switched outlet box, and was looking for a way to reuse it.
He hooked up the outlet box into the “battery powered” side of the UPS, and inserted a light bub into the normally closed half of the switch box. A 5v power supply was hooked into the “surge protection only” side of the UPS and is used to keep the relay switched. This causes the half of the switch box that is normally closed to remain open, and the light switched off. When power is lost, the 5v supply no longer switches the relay, and the light is turned on – powered by the UPS battery.
This is quite a useful hack if you happen to have a spare UPS sitting around – it sure beats scrambling around searching for a flashlight in the dark!
In 1997 [Michael Butkus Jr.] found an uninterruptible power supply in the dumpster. The batteries were shot, but he needed a backup to keep his pellet stove running for heat, drive the exhaust fan to keep the smoke out of the house, and power his computer and other electronics. After a bit of head scratching he decided to beef up the UPS using deep-cycle batteries.
He actually built two of these. One is smaller, and similar to what we’ve seen before. The other is larger and uses four batteries, two pairs in parallel which are then connected in series. He’s careful to use heavy gauge wiring and 50 amp fuses for each battery, both of which will protect against the risk of fire. One thing we found interesting is that the batteries are stored in the basement, directly below the UPS which is connected via a short run of 12 gauge home electrical wire.
We were happy to see that he’s done updates at the top of his post over the years. He lost a few batteries due to neglectfully letting the water levels drop too much. He did switch over to sealed automotive batteries sometime in 2004 or 2005. Looks like things have been going strong ever since.
[Surferdude] was unhappy with the decreasing life of his aging uninterruptible power supply. He decided to beef it up using marine batteries. He extended the battery connections outside of the UPS case using #10 wire and swapped the two 12 volt gel cells with the heavy duty lead-acid batteries. Doing so upgraded the device from 20 amp-hours to 84 amp-hours at a cost of about $160. If you’re thinking about taking this on yourself, pay attention to the countinuous output rating of your UPS to prevent a fire risk.
On a recent trip to New York City, [sherri] noticed the abundant “NYPD Security Camera” signage. She Ò on her little sousveillance tour and did some digging to learn more about the system. According to a recent NY Post article, the city intends to have 2,000 cameras installed by 2009. Each unit has at least two cameras, an onboard DVR, battery backup, a webserver, and wireless connection. The CrimeEye product line is manufactured by Total Recall—the people who brought you BABYWATCH. While the company site doesn’t list any specs, we found a price list that was provided to New York State. Each unit lists for $28-39K. They can have image sensors up to 2 megapixels, hold 30fps video for 5-15days, and transmit wirelessly on the 4.9GHz public safety band.
[sherri] wonders what systems are in place to guarantee the security of the camera network and to make sure the data is handled properly. We’ve seen bad implementations of cameras with webservers
in the past. She suggests a third-party system to verify security, operation, and storage. Right now there’s no reason the government won’t use footage for invasive data mining. As a publicly funded system monitoring public areas, we see no reason why the video streams from these devices shouldn’t be widely available.
Come on, folks. If we keep tearing apart everything that’s handed to us, we’ll never get nice things. SparkFun got their mitts on two Kill A Watts and proceeded to plug them into everything and then dismantled them to see how they work. The Kill A Watt keeps track of how much power is used over time. The largest load they found was their soda machine using 500W (should probably add a motion sensor to that). They plugged a meter on either side of a UPS and found out that it uses 5W just to charge. On the inside of the meter, there isn’t anything too substantial. One unlabeled IC runs the whole show.