If you’ve been to downtown San Francisco lately, you might have noticed something odd about the decorative trees in the city: they’re now growing fruit. This is thanks to a group of people called the Guerrilla Grafters who are covertly grafting fruit-bearing twigs to city tress which would otherwise be fruitless. Their goal is to create a delicious, free source of food for those living in urban environments.
Biology-related hacks aren’t something we see every day, but they’re out there. For those unfamiliar with grafting, it’s a process that involves taking the flowering, fruiting, or otherwise leafy section of one plant (a “scion”) and attaching them to the vascular structure of another plant that has an already-established root system (the “stock”). The Guerrilla Grafters are performing this process semi-covertly and haven’t had any run-ins with city officials yet, largely due to lack of funding on the city’s part to maintain the trees in the first place.
This hack doesn’t stop at the biological level, though. The Grafters have to keep detailed records of which trees the scions came from, when the grafts were done, and what characteristics the stock trees have. To keep track of everything they’ve started using RFID tags. This is an elegant solution that can be small and inconspicuous, and is a reliable way to keep track of all of one’s “inventory” of trees and grafts.
It’s great to see a grassroots movement like this take off, especially when it seems like city resources are stretched so thin that the trees may have been neglected anyway. Be sure to check out their site if you’re interested in trying a graft yourself. If you’re feeling really adventurous, you can take this process to the extreme.
Thanks to [gotno] for the tip!
[Hasbi Sevinç] is using perishable goods in his electronics project. The orange, tomato, and two apples seen above act as keys for the virtual piano. The concept is the same as the Makey Makey which is often demonstrated as a banana piano. This implementation uses an Arduino to read the sensors and to connect to the computer running the piano program.
You can see there’s a fair amount of circuitry built on the breadboard. Each piece of fruit has its own channel to make it into a touch sensor. The signal produced when your finger contacts the food is amplified by transistors connected in a Darlington pair. That circuit drives the low side of a optoisolator transmitter. The receiving side of it is connected the I/O pin of the Arduino. You can see the schematic as well as a demo clip after the break.
This use of hardware frees up a lot of your microcontroller cycles. That’s because projects like this banana piano use the timers to measure RC decay. [Hasbi’s] setup provides a digital signal that at most only needs to be debounced.
Continue reading “Fruit piano uses a different circuit than the Makey Makey”
[BiOzZ] built a pressure sensitive camera accessory to snap pictures at just the right moment. Before turning out all the lights the camera is set up with a twenty-second timer and a three-second exposure. The pressure plate doesn’t take the photo, but fires the flash to catch an image in the middle of the action.
The hack uses a piece of acrylic as the base of the pressure plate. A switch is constructed by placing aluminum tape on the base, and attaching a thin metal strip that is bent to add just a bit of spring. When an object is place on the plate the thin metal contacts the aluminum tape completing the circuit, a change in the weight breaks it. A simple circuit connects to this, using a relay to actuate the flash from a disposable camera. This is perfect for documenting the moment when you exercise that fruit-induced rage that has been consuming you lately.
Ever annoyed by those pesky stickers on your fruit? They never seem to pull off in one piece and they always leave a little glue behind. Well, the industry might be moving away from them in favor of laser etching each piece of fruit. They are using a low energy carbon dioxide laser to etch the skin. The FDA is in the final stages of approval for using this in the states. It is already in use in New Zealand. We might find this a bit weird, but we’ve seen weirder.