5 Feb

HydroBot: Connecting the Modules

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.

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14 Sep

HydroBot: Switches and Relays

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 »

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5 Aug

The CANable USB to CAN adapter is now cheaper and back in stock!

CANable Open-Source USB to CANbus adapter

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.

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15 Jul

HydroBot: Measuring Atmospheric Conditions


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 »

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1 Jul



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 »

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6 Mar

Therm RTD

Therm RTD

Therm RTD is an addition to the Therm PID Controller family, with support for RTD temperature sensors. RTDs (or Resistance Temperature Detectors) use a coil of fine wire made from a material (usually platinum, copper or nickel) that has a very predictable temperature coefficient of resistance (or change in resistance as temperature changes). RTDs are generally more accurate and stable than thermocouples, and have a much greater range than thermistors – although they can tend to be more expensive than both. Read more »

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29 Feb

FeatherHAB Source Code Released!

featherhab-0.1FeatherHAB hardware and software source code are now available for download! The hardware is released under the Attribution-ShareAlike 4.0 International license and the firmware is released under the GNU Affero Public License.

FeatherHAB Features:

  • STM32F0 microcontroller
  • SI446x transmitter broadcasting APRS on 144.390MHz
  • ublox MAX8 GPS module for position tracking
  • Buck-boost power supply for running off of single LiMnO2 cells
  • Opencm3-based firmware compiled with GCC ARM

A st-link programming adapter, blackmagic probe, or similar is required to flash FeatherHAB boards. You will also need some means of connecting to the programming pads on the FeatherHAB PCB. You can solder wires directly to the programming pads, or you can build a ProtoProg adapter.

Building your own FeatherHAB or modding the design? Drop a comment below and share your progress!

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28 Feb

Open-Source SWD Programming Adapter


After making the switch from AVR to STM32 microcontrollers, I redesigned my old 6-pin ICSP pogo-programming adapter for SWD. The new design allows programming with pogo pins or a small pin header soldered to the pogo pads for debugging, all with the same cable. The footprint uses surface mount pads only, so it can be placed on even the most compact board layouts.

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27 Feb

CANable now available for purchase!


The CANable USB to CAN adapter is now available for purchase on the Protofusion Tindie store! The CANable is an open-source USB to CAN adapter that works on Linux, Mac and Windows. The CANable shows up as a virtual serial port on your computer and provides a standard serial-line CAN interface. CANable is also compatible with a Python CAN library so you can easily code scripts that interface with the bus. Check out canable.io for more information.

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6 Dec

Tenergy LiFePO4 CR123 Cell Test


I stumbled upon Tenergy’s lithium iron phosphate CR123 cells when looking for a fairly compact cylindrical rechargeable battery. The Tenergy RCR123A LiFePO4 cell, as listed on Tenergy’s website, supposedly has a nominal voltage of 3v and a nominal capacity of 750mAh. Both of these values seemed a bit unusual, so I ran the battery through a discharge test to get some realistic data on what this cell is capable of. Note that many consumer battery manufacturers publish capacity numbers that are more than 200% of the real-world value, so this isn’t a unique case.

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