[Eric Maundu] is farming in Oakland. There are no open fields in this concrete jungle, and even if there were the soil in his part of town is contaminated and not a suitable place in which to grow food. But he’s not using farming methods of old. In fact farmers of a century ago wouldn’t recognize anything he’s doing. His technique uses fish, circulated water, and gravel to grow vegetables in whatever space he can find; a farming method called aquaponics.
The video after the break gives an excellent look at his farm. The two main parts of the system are a large water trough where fish live, and a raised bed of gravel where the fish waste in the water is filtered out and composted by bacteria to becomes food for the vegetables. More parts can be added into the mix. For instance, once the water has been filtered by the stone bed it can be gravity fed into another vessel which is being used to grow lettuce suspended by floating foam board. But the water always ends up back in the fish trough where it can be reused. This ends up saving anywhere from 90-98% of the water used in normal farming.
But [Eric] is also interested in adding some automation. About seven minutes into the video we get a look at the control systems he’s working on with the help of Arduino and other hardware.
Continue reading “Urban farming uses aquaponics to make farmland where there is none”
If you happen to visit the Spanish port of Gijon, you may notice some giant yellow robotic fish swimming around. These 5 foot long swimmers are part of a proposed sensor network to detect pollutants in the water. Equipped with an array of sensors, the fish can test for general water quality, or swap out the sensors for specific testing. They communicate with each other to keep from straying too far from the rest of the network and the base charging station.
The fish was designed by the Shoal Consortium, a European commission funded program that draws from intelligent minds in universities all over europe. While the fish cost over $35,000 right now, mass production should reduce that cost considerably.
You can see them swimming around in the BBC video at the link.
Anyone who owns a fish tank knows that a good amount of care is required to keep fish happy, healthy, and most of all – alive. [Vicente Jiménez] usually has no problem keeping up on the day to day maintenance such as feeding and switching the tank light, but he wanted to automate these processes for times when he can’t be home to take care of the fish (Translation).
His aquarium automation project is meant to cover three separate parts of the operation: light control, feeding, and pump regulation during feeding times. [Vincente] picked up an STM8L Discovery board to control his system, which enabled him to easily control the automation of all three.
He constructed the feeding mechanism using an old cassette player motor, which turns his food drum (an old film canister), twice a day at specified feeding times. Before the drum is turned to dispense food, the STM8L turns off the aquarium’s pump via a relay to ensure it doesn’t get clogged in the process. During the day he keeps the tank illuminated, but once night falls, the microcontroller shuts the lights off so the fish can get their rest.
There’s no video of the system in action, but [Vincente] has detailed its construction pretty thoroughly in his blog, so be sure to check it out if you are in need of something similar.
When you have a virtually unlimited budget, you can pull off some amazing things. This has become most evident recently as the CIA has been showing off some of its old tech. That dragonfly you see above is near life-size and actually flies. They hired a watch maker to build a tiny internal combustion engine to run it. That alone is pretty amazing, but this thing was actually flying in the 70’s. Upon further inspection of the wings, we actually have no idea how this sucker is supposed to fly. Despite our skeptical viewpoint, you can see a tiny clip of it flying after the break. You can also catch a video of “charlie” the robot catfish.
Continue reading “The CIA’s amazing bots”
[Ken] found that using traditional tweezers is a good way to lose tiny surface mount parts and so set out to make his own vacuum tweezers (PDF). He already had a small aquarium pump that he used as a bubbler for etching circuit boards. After opening up the case he found it was possible to connect tubing to the input of the pump to use as the source for the vacuum. The business end of the device is a syringe which he already had for applying oil in tight spaces. A file took off the sharp tip, and a small hole lined with a bit of soft tubing serves as a valve. Put the needle tip in place and plug the hole with your finger to pick it up. Works like a charm and will go well with our next feature, building your own reflow skillet.
We like [Ken’s] work. We just looked in on his copper clad enclosures yesterday.
This automatic fish feeder didn’t take long to put together and it allows you to adjust how much food is dispensed. [Gagandeep Singh] built it around an Atmel AT89C2051 microcontroller. Like many of the automated feeding systems we see, this uses a character display and a few buttons for the user interface. We’re always curious at how they mechanically dispense the food. In this case, the motor seen at the left pulls open a sliding baffle which is pulled closed again by rubber bands at the right. It’s a bit more involved than the last fish feeder we saw, but your guess is as good as ours on which system works better.
[Patrick Becker] had an ancient PC on his hands with a blown PSU. He converted this into a stylish home for his Betta splendens.
The aquarium itself is fashioned from a piece for construction glass block with the top cut off. This allows for a window that looks through the tank and shows off the motherboard on the other side. He patched into the AC connector so that the original power cord can be used to control the pump. A lighted pump button was added to the front panel and a fancy bezel fitted to the viewing portal in the side of the case. He finished off the project with a PVC pipe for air and food. His blue screen of death now features water and a real fish.