Automated pH Control

pH Controller

Controlling the pH level of a solution is usually a tedious task. Adding an acid or base to the solution will change the pH, but manually monitoring the levels and adding the correct amount isn’t fun. [Reza] rigged up an automated pH controller to keep a solution’s pH steady.

The build uses an Arduino with a LCD shield, screw terminal shields, and [Reza]‘s own pH shield attached. A peristaltic pump is used to pump the pH down acid into the solution. This type of pump isolates the fluid from the pump parts, preventing contamination of the solution. The pump is controlled using a PowerSwitch Tail, allowing the Arduino to control the flow of fluid.

An Omega pH probe is used to read the pH level. [Reza]‘s open source firmware has support for calibrating the probe to ensure accurate readings. Once it’s set up, the screen displays the pH level and the current state of the system. The pump is enabled when the pH rises out of the desired range.

After the break, check out a video walk through of the device.

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No sleep till Brooklyn aquaponics installation is complete


This is some extreme gardening. [I Am Become Derpth] didn’t let lack of space or tillable soil stop him from growing a bountiful harvest. Instead of cutting though prairie sod to begin the farming he had to contend with the concrete expanses found in the NYC area. Here he’s nearing the end of an impressive aquaponics installation in Brooklyn, New York.

For a good overview of what aquaponics is all about we suggest you take a look at this Oakland, CA setup. The heart of the system is a closed loop that uses both plants and fish for balance. The byproduct is edible greens. The image above shows the growing beds through which water is circulated. They’re filled with clean gravel which keeps the roots happy. Once the water has made it through this system it is piped into the basement of the apartment where water tanks filled with fish reside. The system uses the fish waste (broken down by bacteria) to feed the plants.

It’s an efficient system but one thing’s for sure, you don’t just go out and buy a rig this complicated. We think you’ll really enjoy going through the build log linked at the top.

[via Reddit]

Urban farming uses aquaponics to make farmland where there is none

[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.

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Hydroponic strawberries sweeten up winter dolldrums

Add some fruit to your indoor bounty with this hydroponic strawberry farm. [Dino] whipped this up as his 45th hack a week episode (getting pretty close to his year-long goal). He used parts you probably already have sitting around the house somewhere. But even if you bought everything and used it once you still wouldn’t be out much.

A plastic storage container serves as the base. [Dino] also grabbed four identical plastic containers (large yogurt containers would work here) to host the plants. He cut off the bottom half and inserted some netting to keep the plant from falling through. After tracing the size of the container on the enclosure’s lid he cut out holes which will host each plant. This provides a way to dangle the roots into the nutrient solution which is kept oxygen rich with an aquarium pump and two air stones. It certainly deserves a place next to that salad farm you threw together. Don’t miss [Dino's] build video after the break.

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Grow your own fresh salad year round with this cheap hydroponic setup

With fall approaching you might think about moving your gardening inside. [Jared] used cheap and readily available materials to make these salad-green trays.  When used with his grow lights and tent (which he built during a different project) he was able go from seed to salad-bowl in just four weeks.

A pair of plastic storage bins act as the base, keeping the water right where it should be. Some holes cut into a piece of solid foam insulation holds a set of plastic pots in place, allowing the water to leech into the Rockwool that holds each plant in lieu of soil. To aerate the water [Jared] grabbed a cheap aquarium pump, splitting the output into several different branches. Each has its own check valve to ensure that a pump failure doesn’t let the water find its way out of the plastic tube. A set of bubble stones breaks up the output, helping to mix it with the water.

This isn’t quite as easy to pull off if you don’t already have a grow light. But you can always make it worth the investment if you decide to start next summer’s garden from seed. Or perhaps you can try to make your own using a varation of this shop lighting hack.

[Thanks Jayson]

Repeat timer hacked for 35 minute hydroponic cycles

[GrowColt] shows you how to modify a lamp timer for use with hydroponics. You can pick up this type of mechanical timer at most local big box stores for around $5. The timer plugs into an outlet, and the device you want to operate plugs into it. [GrowColt's] end goal is to make the timer repeat every 35 minutes, routing power to the connected device for about 50 seconds each cycle. It will operate the pumps and misters in his hydroponic garden to keep the plants hydrated and keep the nutrients flowing.

We’ve embedded his detailed process after the break. It’s not all that difficult, requiring a few common hand tools, some glue, and rubber washer. There’s a gear box inside which controls the timer. Reorganizing that gearing makes it repeat more frequently.

Not into hydroponics, but looking for watering help with your greenhouse? Check out this system which monitors water sensors and dispenses H2O accordingly.

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