Building A Very Low Power, Full Featured Desktop

September 9, 2012 by Brian Benchoff 48 Comments

For a few years now, [mux] has been playing around with extremely efficient computation. In 2010, he built a fully featured MiniITX / Core 2 duo computer that only consumed 20 watts. Last year, [mux] managed to build an Intel i3-powered desktop that was able to sip a mere 8.3 watts at idle. He’s back at it again, and now his sights are set on a fully featured Intel i5-powered build with a built-in monitor that will draw less than 6 watts of power.

Like his previous 8 watt i3 build, [mux] reduces the power requirement of his build by carefully measuring the power draw of every component on his board. The power savings come from a simple fact of any power supply; when converting from AC to DC, or from one DC voltage to another, there’s always a little bit of power lost in the process.

[mux] reduces these power losses by removing a few voltage regulators and re-routing power lines across his motherboard. So far, the power draw on [mux]’s computer is more than half of what it was when the parts were stock, and we can’t wait for the finished build that includes a built-in monitor, UPS, and a proper case.

CRT Reborn As A Planter

August 18, 2012 by Mike Szczys 18 Comments

It does make us sad to see all the waste generated as we move from CRT monitors and televisions to flat panel offerings. Here’s a way to cut down just a bit on how much is going to waste. [Denizpa] turned a CRT monitor into a planter.

The project is very straight-forward. First remove the plastic body from the electronic guts. Next you’ll want to choose your paint colors. While you’re at the home store, pick up a sanding sponge as well. [Denizpa] used 320 grit to sand all of the outside surfaces to help ensure the paint would bond well. Once the paint dried four plastic corner brackets were screwed in place to add some interest to the bottom of the planter. It’s not quite time to plant though, there’s way too many holes in the case to just fill it up with soil. A black plastic garbage bag serves as a liner and completes the project.

No mention on what to do with the guts you removed. If you have an idea let us know in the comments section.

Watering System For Your Vegetable Garden

August 15, 2012 by Mike Szczys 21 Comments

The vegetables will be alive when [Dillon Nichols] returns from vacation thanks to this automatic watering controller that he built. This is the second iteration of the project, and deals mainly with replacing the electronics and UI of the controller itself. He detailed the hardware used for watering in a previous post. He plumbed in a solenoid valve with a hose threading on the output end for the soaker hoses snaking through the garden beds. This is a normally open valve but we’d suggest using a normally closed valve as a power outage will let the hose run continuously.

[Dillon] prototyped the design on an Arduino board, then moved to a standalone ATmega328 chip on some protoboard for the final design. He used a 3D printer to make the custom face plate which allows access to the three control buttons and provides a place for the character LCD to be mounted. In addition to the timer settings there is a manual watering switch as well. He used a typical mains light switch, wiring it with a pull-down resistor to make it work well with the Arduino. His explanation of the timer system can be seen after the break.

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Make A Cardboard Bookshelf In Less Than A Day

July 27, 2012 by Mike Szczys 8 Comments

Lucas came up with a real winner when upcycling cardboard to use as a bookshelf. It’s visually pleasing, can be built basically for the cost of glue and a mounting brackets, and you don’t have to feel bad if you decide to get rid of it later on.

What he saved in raw material cost he spent in labor. There are 23 different layers of cardboard that went into the project, not including the spacer squares between each piece. The vast majority of the time spent in the clip after the break shows a fast-time video of him cutting out the layers. It apparently took about eight hours of cutting, and we’d image he’s got a claw of a hand after all of that work.

This is hanging from a single L bracket positioned in the square opening with two nails to keep it level. We’d suggest including a better mounting technique in your design. If you have some ideas about this please let us know in the comments.

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Driving Your Home Appliances With Hybrid Power

July 22, 2012 by Mike Szczys 19 Comments

This system of hybridizing your home’s electric appliances is an interesting take on solar energy. It focuses on seamlessly switching appliances from the grid to stored solar energy as frequently as possible. There’s a promo video after the break that explains the setup, but here’s the gist of it.

Follow along on the pictograph above. We start on the left with solar panel. This feeds to a charger that tops off a 12V battery. When that battery is full, the charger feeds to the inverter which converts the 12V DC to 110V AC power. This is fed to a pass-through which is in between the appliance (in this a case a lamp) and the wall outlet. The pass-through will switch between mains power coming from the outlet, and the 110 coming from the inverter. The homeowner won’t know, or care, which power source is being used. But sunny months should result in lower energy bills. The real question is how long it takes to cover the cost of the system in saved electricity.

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Monitoring Your Home Energy Use

July 18, 2012 by Mike Szczys 19 Comments

[Dave’s] been elbow-deep in mains voltage while building this home energy monitoring rig. He started with an approach that is different from most we’ve seen before. He wanted a system that could make a linear measurement to keep the accuracy as high as possible. His first thought was to use a opto-isolated linear amplifier to measure voltage, but ended up altering that plan since he’s looking for digital values when all is said and done.

He’s using an ADC on the mains side of the interface board, then sending the digital values to an Arduino with opto-isolators to keep the high voltage separate from the low. This does complicate things a little bit, as he has low voltage rails on either side; 0V and 5V to run the ADC on the mains side, and separate 0V and 5V to run the Arduino. To solve the problem of accurate current measurement over the full range a house uses he opted for a Programmable Gain Amplifier. It’s addressed via SPI and allows him to adjust resolution to facilitate accurate measurement of very small currents. We think anyone who has tried to measure small appliances (like an alarm clock) with a Kill-A-Watt and gets a zero reading will appreciate this.

The Arduino sends data via a serial connection, which [Dave] is currently graphing using his laptop. It would be nice to see a simple web-server using the Ethernet shield (or a different board like the RPi) so you could log in from the couch and see what’s been going on with your home grid.

Solar Oven Built To Last

July 11, 2012 by Mike Szczys 18 Comments

The problem with most solar ovens is that they’re flimsy builds that will stand up to only a handful of uses. But this one stands apart from that stereotype. It’s big, sturdy, and used a lot of math to efficiently gather the sun’s energy when cooking food.

This is the third version of the build and each has included many improvements. The obvious change here is a move from aluminum reflectors to actual mirror reflectors. These attach at a carefully calculated angle to get the most power from the rays they are redirecting. The orange mounting brackets for the mirrors also serve as a storage area for transport. The rectangular reflectors fit perfectly between them (stacked on top of the tempered glass that makes up the transparent side of the cooking chamber).

The body of the oven doesn’t track the sun and one of the future improvements mentions adding tilt functionality to the base. We’d suggest taking a look at some of the solar tracking setups used for PV arrays.

[Thanks John]