Scratch-build Garden Nursery Uses Arduino Monitoring

Starting your garden indoors helps to ensure large yields. This is because the plants get a head start before it’s warm enough for them to be put in the ground. But the process involves a fair amount of labor, ensuring that the lights are turned on and off at the right times each day, and that the temperature for germination and growth, as well as humidity, hit a certain target. It’s obvious that a bit of automation would be nice, and this Arduino-based garden nursery does just that. One of the things that sets this project apart is that it shows you how to go from an empty room to the bounty of plant starters seen here.

For the most part the equipment is what you’d expect, seed trays and covers, tray warming mats, and fluorescent light fixtures. the whole thing is given a small footprint thanks to an adjustable shelving unit. The Arduino is used in conjunction with a Sprout Board to add connectivity for switching the lights and warming mats. This is just a matter of driving a relay to switch mains voltage and can take any number of forms, including this home automation project we saw the other day.

[Thanks Tom]

The Dronitar; A Scrap Made Motorized Sitar

This peculiar instrument, called the Dronitar,  is completely made from scrap. Interestingly, it sounds pretty good. You can hear the dronitar in action in the video after the break.The call this a  “2 stringed” instrument,and most who are instrumentally savvy will find a bit of confusion here. They are referring to the string that you play as well as a small string that is struck against the other by a motor to create the droning effect. The result sounds very much like a sitar mixed with a bit of surfer rock styling.  You’ll note that they’re even using a second motor as the pickup!

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DIY Solar Collector Boost Your Hot Water System

This home is heated by a wood stove in the winter, which also produces hot water. But the other three seasons it’s an electric water heater that does the work. This latest hack is a solar collector meant to take over the hot water production work for the house. it uses basic building materials and rudimentary construction skills, making it much more approachable than trying to make electricity from the sun.

It’s really just a wood box with a glass lid. The inside has been painted black, and the black tubing that snakes through it holds the water. A three-way valve lets the homeowner patch into the hot water reservoir. The collector is lower than the reservoir, so the heated water makes its way back into the tank as cooler water takes its place. Not bad for an entirely passive system!

[Thanks Minde]

Heliowatcher Positions Solar Panels For Highest Efficiency

[Jason Wright] and [Jeremy Blum] are showing off the project they developed for their Designing with Microcontrollers course at Cornell University. They call it the Heliowatcher, and if you know your Greek mythology we’d be you figured out this watches the movement of the sun and adjust a solar panel to follow it.

Their design is simple and effective. The base is mounted like a Lazy Susan, able to pivot on the horizontal plane. The bottom edge of the solar panel is mounted with two door hinges, with a motorized screw jack used to raise and lower it. The system uses a GPS to provide geographical position, day, and time feedback. This is used in conjunction with an array of four LEDs to determine the best position of the panel. Those LEDs are acting as light sensors; when the top and the bottom detect similar levels, the panel is at its most efficient orientation. The left and right LED sensors work the same way.

Now if we can just work out a self-cleaning system to keep the panels free of the dirty film that builds up over time we’d be set!

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Prototyping A Solar Charger For Your Truck

[Bryan] got his hands on a solar panel and decided to take it on the road rather than throwing it on the roof of the house. On sunny days it will top off the car battery, letting him use his stereo in the middle of nowhere without needing to keep the engine running. Instead of buying a ready-made solution he chose to design and build his own charging circuitry.

The charger uses an Arduino, which draws its own power from the panel via a regulator. It senses the voltage level of the battery and the available juice from the panel, connecting or disconnecting it from the electrical system as necessary. The system includes a set of LED indicators, which he installed in the dashboard near the cigarette lighter. This also gave him an excuse to install a voltmeter which uses a 2.5 digit seven segment display to read out the battery voltage. You can see a brief overview after the break.

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Recycle Lithium Cells By Building Custom Flashlights

This isn’t a brightest flashlight in the world type of hack (but it does manage to push about 1000 lumens). [Stephen Webb] is finding a use for leftover parts by building his own simple LED flashlights. As you can see, he uses PVC parts available at any hardware or home store. These are a good choice; they’re cheap, light weight, resilient, designed to be water tight, they easily thread together and have connectors that reduce the diameter of the fittings.

The electronics use standard size cylindrical Lithium cells. These are found in many types of Laptop and Power Tool batteries. Often when one of those battery packs bites the dust it’s an issue of one or more bad cells. [Stephen] desolders the cells, and reuses the good ones in this project.

We didn’t see any mention of a recharging technique. Does anyone have any advice on how to top these cells off if they’re not in their original power pack form?

Generating Electricity With Swing Sets

[Guelherme Pena Costa] came up with an idea to light up a swing set using the motion of the people swinging on it to generate electricity. The goal was to get people to enjoy the playground at night and we think, this might actually be a pretty good way to achieve that. People love blink lights, especially if they are interactive.

To Light the LEd ropes, [Guelherme] has attached a gear motor to the frame of the swing set and an arm to the chain. When the swinger swings, it spins the motor generating between 6 and 10 volts at 230-400 mA. As you can see in the video below, that works fine to illuminate the LEDs, though we think a charging circuit to allow the lights to stay lit for longer would also be cool.