[Shawn] recently overhauled his access control by fitting the doors with some RFID readers. Though the building already had electronic switches in place, unlocking the doors required mashing an aging keypad or pestering someone in an adjacent office to press a button to unlock them for you. [Shawn] tapped into that system by running some wires up into the attic and connecting them to one of two control boxes, each with an ATMega328 inside. Everything functions as you would expect: presenting the right RFID card to the wall-mounted reader sends a signal to the microcontroller, which clicks an accompanying relay that drives the locks.

You may recall [Shawn's] RFID phone tag hack from last month; the addition of the readers is the second act of the project. If you’re looking to recreate this build, you shouldn’t have any trouble sourcing the same Parallax readers or building out your own Arduino on a stick, either. Check out a quick walkthrough video after the jump.

Read more on MAKE

Read more on MAKE

Read more on MAKE

Read more on MAKE

Read more on MAKE

Marco Pucci shared on our Facebook Page a link to the tutorial he made for a low-cost Robotic Hand able to mirror the movement of our own hand. He created it  in the laboratory of new technology of Accademia di Belle Arti di Brera (“Academy of fine arts of Brera”), a state-run public academy in Milan, Italy.

The hand works with flex sensors attached to the glove’s fingers, they are analysed by an Arduino which then moves servo motors connected to threads attached to the robotic hand.

You can follow the tutorial (in italian, but you can use google translate) on this page www.marcopucci.it/arduino/ , download a zip with all the sketches, and watch a demo video below:

Read more on MAKE

Read more on MAKE

It’s great having fresh vegetables just a few steps away from the kitchen, but it takes work to keep those plants healthy. [Pierre] found this out the hard way after returning from vacation to find his tomato plant withering away. He decided to put an end to this problem by building his own solar-powered plant watering system (page in French, Google translation).

An Arduino serves as the brain of the system. It’s programmed to check a photo resistor every ten minutes. At 8:30PM, the Arduino will decide how much to water the plants based on the amount of sunlight it detected throughout the day. This allows the system to water the plants just the right amount. The watering is performed by triggering a 5V relay, which switches on a swimming pool pump.

[Pierre] obviously wanted a “green” green house, so he is powering the system using sunlight. A 55 watt solar panel recharges a 12V lead acid battery. The power from the battery is stepped down to the appropriate 5V required for the Arduino. Now [Pierre] can power his watering system from the very same energy source that his plants use to grow.