Hackaday Prize Entry: Open Source Hydroponic Monitoring System

A few months ago, [Adam] was building a controller system for a small hydroponic system he had set up in his basement. Since then, the Hackaday Prize was announced, and given the theme – saving the world one plant at a time – he’s renvisioning his garden control and monitoring system as a Hackaday Prize entry.

While the mechanical and green part of the build is exactly what you would expect from something designed from hardware store parts, the electronics are rather interesting. All the plants in either a hydroponic or dirt-based setup will have their moisture level and PH monitored by a a set of electronics that push data up to the cloud.

The current hardware setup includes a DyIO, a very cool dev platform with 24 digital I/Os and 24 servo outputs, a Raspberry Pi, and a few module boards loaded up with ARM microcontrollers and an ESP8266. [Adam] is hitting all the hardware on this build.

So far, [Adam] has a few boards sent out to a board fab, including an analog sensor module, a digital sensor module. a WiFi module hub, and a few bits and bobs that make integration into an existing garden or hydroponic setup easier. It’s a great project for this year’s Hackaday Prize, and proof that you don’t need to come up with a new build to submit something.

The 2015 Hackaday Prize is sponsored by:

Fully automated watering robot takes a big leap forward toward greenhouse automation


Greenhouse owners might find [David Dorhout]’s latest invention a groundbreaking green revolution! [David]’s Aquarius robot automates the laborious process of precision watering 90,000 square feet of potted plants. Imagine a recliner sized Roomba with a 30 gallon water tank autonomously roaming around your greenhouse performing 24×7 watering chores with absolute perfection. The Aquarius robot can do it all with three easy setups; add lines up and down the aisles on the floor for the robot to follow, set its dial to the size of your pots and maybe add a few soil moisture sensors if you want the perfect amount of water dispensed in each pot. The options include adding soil moisture sensors only between different sized plants letting Aquarius repeat the dispensing level required by the first plant’s moisture sensor for a given series.

After also digging through a pair of forum posts we learned that the bot is controlled by two Parallax propeller chips and has enough autonomous coding to open and close doors, find charging stations, fill its 30 gal water tank when low, and remember exactly where it left off between pit stops. We think dialing in the pot size could easily be eliminated using RFID pot identification tags similar in fashion to the Science Fair Sorting Project. Adjusting for plant and pot size as well as location might easily be automated using a vision system such as the featured Pixy a few weeks back. Finally, here are some featured hardware hacks for soil moisture sensing that could be incorporated into Aquarius to help remotely monitor and attend to just the plants that need attention: [Andy’s] Garden sensors, [Clover’s] Moisture control for a DIY greenhouse, [Ken_S’s] GardenMon(itoring project)

[David Dorhout] has 14 years experience in the agriculture and biotech industry. He has a unique talent applying his mad scientist technology to save the future of mankind as seen with his earlier Prospero robot farmer. You can learn more about Aquarius’s features on Dorhout R&D website or watch the video embedded below.

Continue reading “Fully automated watering robot takes a big leap forward toward greenhouse automation”

Analog soil moisture alarm

The lion’s share of soil moisture monitors we see are meant as add-ons for a microcontroller. So we’re glad that [Miceuz] tipped us off about this soil moisture alarm he built with analog parts. It’s really not hard to take the concept and build it in the analog world. That’s because you’re just measuring a resistance value. But for those of us who never really got started with analog parts this is a great project to learn from.

A high-efficiency op-amp is doing the brunt of the work. When the soil is moist the resistance is rather low compared to a reference voltage provided by a separate resistive divider. But when the plant gets thirsty and the soil dries out the resistance increases, triggering the op-amp to illuminate an LED and create some noise on the buzzer (we’re a bit confused on how that buzzer works).

Unfortunately this isn’t a viable long-term solution as the battery calculations show it lasting only about four months. That’s where a microcontroller-based circuit really shines, as it can put it self in low-power sleep and wake infrequently to take readings.

Garden sensors measure soil moisture and greenhouse temperature

[Andy] is getting his garden up and running. This year it’s been pretty cold so he decided to get small plastic domed tunnel which acts as a mini greenhouse. To help monitor that environment he built this sensor array which displays temperature and soil moisture readings.

Temperature is quite simple. He’s using a TMP36 sensor which is held a few inches above the soil. The moisture sensor is of his own design. It uses two building screws embedded in foam. These are pushed into the soil and a resistance reading indicates moisture level. By driving voltage on one screw, and measuring voltage on the other he gets some useful data. It’s not a standardized value, but observation over time will let him know how the scale relates to dry or wet soil.

During the build process he found that he needed a pull-down resistor on the probe used to take the moisture measurement. He also uses an I/O pin to drive the other screw. This gives him a way to shut off the juice when not taking a reading. We just hope he’s either got a current limiting resistor, or is using a transistor to drive it high.

Soil moisture sensing

These plugs are cheap, easy to make, and work well for measuring the moisture content of soil. The Cheap Vegetable Gardener came up with this method in order to add automatic watering to an automated grow system. Plastic tubing is used as a mold for Plaster of Paris. Once the plaster has been poured, two galvanized nails are inserted. These are won’t rust and work as probes, measuring the resistance of the dried plaster (gypsum). When inserted into the soil, the moisture content within the gypsum will fluctuate along with the soil. As moisture rises, the resistance between the probes falls, which can be monitored by a microcontroller and used to trigger or stop a watering system.

[Thanks Juan]

Greenhouse guard


[Seth King] sent in his latest hack where he used an Arduino to regulate various aspects of a greenhouse. He has sensors for soil and air temperature as well as light and moisture. He built a custom circuit that uses relays to power fans, lights, and heaters. Using timers and the sensor data, the devices can be triggered to create the perfect environment for sprouts. He hopes to make the whole thing wireless by integrating XBees, but for now he ran a USB cord to his computer.

Related: Automatic grow light