UPS With Dead Batteries Reborn As A Whole-house Power Backup

April 9, 2012 by Mike Szczys 70 Comments

[Woodporterhouse] must deal with regular power black outs in his area. He recently converted a rack-mount uninterruptible power supply to feed a portion of his mains wiring. This one is not to be missed, since he did such a great job on the project, and an equally remarkable job of documenting it. It’s one of the best examples we’ve seen of how to use Imgur as a project log.

The UPS still needs to have a case, but it doesn’t need room for batteries as he’s going to use a series of high-end sealed lead-acid batteries. So he cut down the enclosure to about half of the original size. That’s it mounted just above the new batteries. For this to work you need some type of transfer switch which can automatically patch between incoming line voltage, and the battery backup. He already had one of these switches in place for use with a generator, that’s it in the upper left. The entire system powers a sub-panel responsible for his essential circuits — the electronics in the home and a few lighting circuits (we’d assume this includes utilities like the refrigerator).

One really great feature that the reused UPS brings to the project is a monitoring card with a NIC. This way he can check the server to see if the UPS is being used, and how much of the 14 battery life remains.

[Thanks Ross via Reddit]

Apartment Entry Morse-code Lock

April 9, 2012 by Mike Szczys 20 Comments

[Bozar88] lives in an apartment building that has a buzzer at the front security door. Guests find your name on the panel next to that door, and press a button to ring the phone just inside the entry of each apartment unit. He decided to extend the built-in capabilities by adding a morse-code entry password which unlocks the security entrance automatically (translated).

He designed a circuit and etched his own board which fits nicely inside of the wall-mounted phone. It uses an ATtiny2313 to implement the coding functions. The device attaches to the intercom line in order to detect incoming button presses from the entry panel. There’s some protection here to keep the signal at or below 5V. The output is two-fold. The microcontroller can drive the microphone line using a transistor, which gives the user audio feedback when the code is entered. To unlock the door an opt-isolated triac (all in one package) makes the connection to actuate the electronic strike on the entry door.

The video after the break is not in English, but it’s still quite easy to understand what is being demonstrated.

Continue reading “Apartment Entry Morse-code Lock” →

Harvesting And Graphing Wireless Household Utility Meter Info

April 9, 2012 by Mike Szczys 46 Comments

Both our electrical meter and our gas meter are located in the basement of our house (we recently had the gas meter moved outside though). When people see this they always ask if the meter readers have to come inside once a month. The answer is no, these meters broadcast usage data which is picked up once a month when a utility company vehicle drives down the street. If you have wireless meters in your house, here’s a way to harvest and graph the wireless data so that you can analyze your usage patterns.

The hardware used here is a special USB dongle. This has a 900 MHz radio which picks out the packets from a reasonably large list of meter types, and pushes them through the USB interface. In the image above you can see that an Arduino with a USB host shield is used, but there are also drivers if you want to connect this directly to your computer.

We looked around and didn’t find any specifics on the hardware used on that board. But it can’t be all that hard to make one of these at home… the populated board seems to have just two ICs and a few passive components. Anyone up to the challenge of hacking together their own packet sniffer? We wonder if the Next HOPE badge could pull down the data?

[Thanks Chris]

Auto-locking Pet Door Ensures That Your Outdoor Kitty Obeys Its Curfew

April 4, 2012 by Mike Nathan 26 Comments

If you’ve got a pet that roams freely in and out of your house, you may find yourself wanting to more closely regulate how they come and go. [tareker] was looking to keep his cat indoors at night when dangerous animals might be lurking in the neighborhood, but he didn’t want it to become a hassle.

He already had locking pet door on hand, which he hacked to regulate the egress and ingress of his cat automatically. He installed a pair of reed switches to determine if the door had been opened outwards (cat leaving) or inwards (cat returning), keeping track of the state using an Arduino Nano. A servo motor attached to the door’s frame locks the door whenever it detects the cat is safely inside after nightfall.

While he also added an RGB LED to reflect the status of the door, he’s considering connecting it to the Internet so that he can control and check the door from wherever he might be at the moment.

Whistle Controls For You Home Electronics

April 2, 2012 by Mike Szczys 19 Comments

You know how to whistle don’t you? You just put your lips together and blow. But do you know how to make the electronics around you react to your whistled commands? Well [Befi] figured out a system that allows him to assign a whistled command to various home electronics.

He’s using a set of RF remote control outlets to switch power to various devices like a desk lap, or a turn table. The board you see in the image above is the remote control that came with the system, but that chip is an ATmega8 which he added to give round-about USB connectivity using a serial-to-USB converter. The technique is simple enough that we’d bet you can get this to work with an ATtiny2313 and the V-USB project but that’s another story.

The additional piece is the use of embedded Linux to detect and process whistled commands. In the video after the break [Befi] explains that he’s using a Dockstar along with a microphone to capture audio input. It uses a Fast Fourier transform algorithm to process the clip and pushes commands to the remote control after processing is complete. Continue reading “Whistle Controls For You Home Electronics” →

Build An Elevator Controller, Gain A Friend For Life

April 1, 2012 by Mike Nathan 49 Comments

diy-elevator-controller

[Michael Ruppe] was working one day when a man named [Kevin] approached him for a bit of help with a project. It just so happened that [Kevin] was in the middle of constructing a DIY residential elevator and he needed assistance putting a control board together.

[Kevin] had no problem casting a forklift ram into his basement slab, nor installing a submersible pump in a custom-made hydraulic pit, but wiring up the controls for the device was just not something he was comfortable with. [Michael] was more than happy to lend a hand, and over the next couple of months the pair got things running nicely.

Instead of relying on a microcontroller, [Michael] built a control board that uses little more than a handful of relays and microswitches to get the job done – It’s certainly not hard to appreciate the controller’s simplicity.

It’s stories like these that remind us just how much the hacker community is willing to help out complete strangers with any task, big or small – you guys rock!

Stick around to see a short demo video [Michael] shot, showing the elevator in action.

Continue reading “Build An Elevator Controller, Gain A Friend For Life” →

Rain Barrel Irrigation System Keeps Your Plants Fed When You’re Too Busy

March 29, 2012 by Mike Nathan 53 Comments

sprinkler-controler

[Kyle Gabriel] moved into a house with a nice tract of land behind it, but due to his busy schedule he had yet to plant the garden he so desperately wanted. He worried that his hectic life and busy hours would lead to accidentally neglecting his garden, so he built a water collection and automated irrigation system to ensure that his plants never went without fresh water.

The system is fed by two large 55 gallon barrels that collect rain from his gutters. A 1/2 HP well pump is used to pressurize the collected water, which is then dispensed throughout his garden by a sprinkler. [Kyle’s] system is run from a small control box where an Arduino is used to control the pump’s schedule. At a predefined time, the Arduino turns the pump on, while monitoring the system for potential problems.

If the system starts running low on water, the Arduino triggers the valve on his spigot to open, keeping the water level above the pump inlet pipe. He also keeps an eye on pump’s outlet pressure, indefinitely disabling it before a blockage causes the pump to cycle repeatedly.

He says that the sprinkler system works quite well, and with his modular design, he can add all sorts of additional functionality in the future.