Deep Water Culture (DWC) is a hydroponic gardening method in which plants are grown directly into a large pool of nutrient solution. Typically, plants are placed in net baskets full of a growing medium such as perilite or expanded clay pellets. These baskets are then placed in a reservoir (5 gallon hardware store buckets are a popular choice among hobbyists) to submerge the plant roots. The root mass will continue to grow down into the reservoir, slowly filling it with loosely packed roots. DWC systems require a well oxygenated nutrient solution to keep the roots from drowning and rotting – an air stone and a bubbler are often used to sustain adequate dissolved oxygen levels. As plants consume water, the reservoir level will recede, exposing the roots to even more oxygen and promoting prolific growth. The downside of frequently changing water levels is that pH and EC levels tend to fluctuate, especially in smaller systems. Maintaining a large number of small reservoirs, such as 5 gallon buckets, can also become tedious. To combat this, recirculating designs are implemented to tie together smaller reservoirs into one large system, which will tend to be much more stable and require less work. Read more »
Continuous Flow or Nutrient Film Technique (NFT) hydroponic systems use a shallow stream (or film) of water recirculating through a channel to deliver nutrients directly to the plant roots. The stream is shallow enough that the uppermost roots laying in the channel are exposed to air, providing the plant with access to lots of oxygen in addition to all the water it needs. To control the depth of the water stream, NTF systems use channels sloped at 1:30 or 1:40 (around 1.5 degrees). For most plants, the optimal flow rate in each channel is 1-2 L/m, and a maximum length of 10-15 meters is recommended to avoid nutrient depletion at the end of the channel. Because NFT style systems rely on a pump for nutrient and water delivery, there is no protection against power outage or system malfunctions. Plants will quickly die if the pump stops running for more than a few hours. NFT systems are best suited for leafy plants, due to the restricted channels which would not be adequate for the massive root structures necessary for most fruiting plants. Read more »
What is WSPR?
WSPR is a low data rate digital protocol intended for measuring RF propagation, typically on LF and HF bands and at very low powers (often 1W to as little as 20mW). WSPR messages are digital packets that contain just a few pieces of data:
- Callsign of sender
- 4-digit grid locator for indicating transmitter location
- Transmit power in dBm
This data allows a listener to know how far away transmissions originated and with how much power the transmission was made, giving a fairly realistic and real-time measurement of RF propagation.
Read more »
What is Hydroponics?
Hydroponics is a method of growing plants without soil, using mineral nutrient solutions dissolved in water. Plants use light to turn water and carbon dioxide into the food they need, through a process called photosynthesis. As long as the plants have enough access to water, air, and nutrients, dirt is not necessary for plants to grow. Read more »
ProtoModule is a HydroBot module designed to easily develop and test new monitoring or control functions that may someday go into a HydroBot module. It has 11 GPIO pins and the power rails broken out on a 0.1” pin header for easy breadboarding or interfacing with ribbon cables. The provided pins give access to a variety of digital and analog I/O, as well as digital communication peripherals, to allow for many flexible design options. Read more »
HydroHub is a HydroBot module designed to connect together HydroBot modules in a star topology. The hub provides power and CAN connectivity to a total of eight channels. It has a DC barrel jack for connecting an external power supply, as well as selectable termination for the CAN bus.
Read more »
RelayDrive is a HydroBot module designed to drive relays and other electro-mechanical devices. It consists of 4 low-side outputs, each rated for 1A continuous current, as well as 4 digital inputs, and is controlled over CAN. This module is intended to drive mechanical relays, solid state relays, and solenoids for controlling devices such as lights, pumps, heaters, fans, and valves in a HydroBot hydroponic system. Read more »
The CANable open-hardware USB to CAN adapter is now back in stock! You can order directly from the Protofusion Tindie store. I dropped the price to $25, making the CANable an even more affordable way to interface with the CANbus. Check out canable.io for more information.
AirSense is a HydroBot module designed to measure air temperature, relative humidity, and barometric pressure. It uses the Bosch BME280 atmospheric sensor to take measurements and sends the results out over CAN. The module can measure temperatures from 0 to +65°C with ±1°C accuracy, humidity from 0 to 100% with ±3% accuracy, and pressure from 300 to 1100 hPa with ±1 hPa accuracy. Three LEDs indicate device status, CAN activity, and error states. Read more »
HydroBot is a modular control system for automating hydroponic gardens. This system is designed with three objectives in mind. First, it will facilitate optimal growing techniques by using scheduling and feedback control loops to maintain state and adapt to changing conditions. Second, it will simplify controls interfaces, making setup and use easier for less tech-savvy gardeners. Finally, the components will be designed in a modular way to increase flexibility and support every imaginable garden configuration. HydroBot aims to bring sensors and actuators together through automation, which will allow hobby growers to focus on growing and not on constantly monitoring and adjusting the environment to keep their garden stable. Read more »