I recently bought some house plant seeds via a mail order seed company. I don’t seem to have the knack of caring for the seeds though. I followed the instructions on the packet but don’t seem to be having much luck in getting any of the seeds to sprout. I am thinking that next time I attempt this I will need some automation on my side. When I was looking into what some other people had done I came across this DIY Soil Moisture Sensor on The Cheap Vegetable Gardener site. There is also lots of cool information on the site for monitoring and controlling plant growing. If you have an extra PC case kicking around you can get some use out of that too!

“You should calibrate the sensor by getting a reading with the probe dry then again when it is full saturated in water.  Ironically, the probe I made was almost exactly specifications as the one I repurposed from a cheap commercial soil moisture sensor so I didn’t even have to modify the constants on the automated computerized grow box software.”

Jonathan from iTrends.dk gave us the heads up about a Denmark team who is building the Worlds most Powerful Private Rocket. Their goal is to send a person into space! Sounds like a blast, but I’m not sure I would want to be the first one to test it out.

“This is a non-profit suborbital space endeavor, based entirely on sponsors and volunteers.
Our mission is to launch a human being into space. We are working fulltime to develop a series of suborbital space vehicles – designed to pave the way for manned space flight on a micro size spacecraft. Two rocket vehicles are under development. A small unmanned sounding rocket, named Hybrid Atmospheric Test Vehicle or HATV and a larger booster rocket named Hybrid Exo Atmospheric Transporter or HEAT, designed to carry a micro spacecraft into a suborbital trajectory in space.”

Tangible Interaction and Macetech (makers of the Shift Bright) were part of the Olympics! They had a hand in quite a few LED installations but the coolest are these Olympic Interactive LED Globes. Macetech talks about the hurdles they had designing and building these devices, due to time constrains and part shortages they had to make some quick decisions in order to meet the deadline.

“The globes are about six feet across, translucent, filled with helium, and contain LEDs that light the sphere in different colors as they slowly bounce across a crowd. We had a solid idea how to proceed at the beginning of the project, but due to worldwide semiconductor shortages, necessary parts were dropping out of stock as fast as they were specified. Every time a part became unavailable, it caused a cascade of design changes that required changing other components, which then became unavailable…and so on. Some parts of the project were completely redesigned several times.”

We use ball bearings all the time. They are used in everything from CNC machines to cars. After you see how much work goes into making one the price of a few dollars seems like such a deal!

The prize this week is a cable tester to help you with troubleshooting. This contest will run for one week (March 6 – 12, 2010) . Ending time is based on central standard time. To enter, identify the item pictured above and give an example of what can be done with it.

Please do not give the answer in the comments.

Send an email to contest @ hackedgadgets.com with “Name the Thing Contest” as the subject, and the message body consisting of:

• The name of the item in the above picture
• An example of what the item pictured above can be used for

The winner will be chosen at random from all of the correct entries.

———————————–———-

Added Mar 27, 2010

The item to guess was a Screen Printing Machine

The winner is Shane V. (there were 81 entries)

————————————–———-

Below are some pictures of the prize.

(more…)

Svofski sent in a neat hard drive clock design he calls Strobeshnik. The clock looks wonderful and he has documented the entire build including how he etched through the aluminum hard drive platters to make the number cutouts. There is a full schematic and code for the microcontroller provided.

“Strobeshnik uses stroboscopic effect to create the illusion of persistent numeric display. The hard drive platter has 10 digits, colon and dash marks, cut all the way through it. Behind the platter, in the HDD chassis, there is a PCB with groups of diffused LED’s. Groups of LED’s in each character position can be strobed independently at any given time. By careful timing of the light strobes, an illusion of still-standing numbers can be created.”

BlackCow from Homebrew Tech has a curious cat who likes to open the front door if it wasn’t properly latched. This Time Delay Door Alarm Project solves that problem by monitoring the door and producing a tone if it has been left open for more than around 30 seconds. This way it isn’t buzzing every time you use the door normally.  The schematic is available on his site if you are interested in making your own.

“When the door opens and the magnetic switch is disconnected the pull up resistor (R2) sets the trigger, on the first 555, high and allows the 33uF capacitor (C1) to charge through the 1 meg-ohm resistor (R1). When the charge reaches 2/3 of the supply voltage the output pin on the 555 is set low. The time it takes for the capacitor (C1) to reach 2/3 of the supply voltage is found by this equation, Time(sec) = (1.1) x (Resistance) x (Capacitance)”