This is the hardware: the physical things a grower builds a monitoring or control system from, from a one-dollar chip to a small Linux computer. Every part gets the same plain treatment: what it is, how to choose it, where to buy it, and where it does not fit.
The sections.
Seven sections below, or browse every hardware page on one filterable list if you already know the part you want.
Microcontrollers
A whole little computer on one chip: cheap, low-power, runs one program. The brain of most sensor and control nodes.
7 pages
Computers
Single-board computers that run a real operating system: the hub that hosts Home Assistant and stores your data.
4 pages
Sensors
The devices that measure the world: temperature, moisture, light, CO2, pH, and more. The largest category.
37 pages
Smart Sensors & Smart Devices
Gear that speaks a protocol out of the box: smart plugs, Zigbee and Matter devices, BLE sensors. The system path.
11 pages
Actuators & Control
The parts that move things: motor drivers, stepper drivers, servo control, relays, dosing, and climate control. Where a decision turns into action.
23 pages
Communications
The foundation everything rides on: Wi-Fi, LoRa, cellular, wired, and the gateways that join them.
12 pages
Power
Keeping it all running: supplies, batteries, solar, Power over Ethernet, and backup. The first thing that fails.
9 pagesWhere to Buy
Sources of supply, from marketplaces to distributors to the specialty shops most growers have never heard of.
LiveHow this is organized.
The site keeps three layers apart so nothing is said twice. Fundamentals teaches the category: what a sensor is, why power matters. Hardware, this section, names the actual things, their specifications, and where to get them. Build is the code and wiring that makes a part do its job. Every hardware page links back to its fundamentals lesson and down to the matching sketch.
A piece of hardware can work on its own, sending its reading straight to a place you own, or as part of a system. The system we embrace is Home Assistant with ESPHome, though it is one good option among several. The software a device runs is described here only as part of the device; a separate Software section will cover software in its own right.
Where to buy.
None of this is exotic, but the sources are not all obvious. The Where to Buy page lists the places to get it, from the big marketplaces to the real electronics distributors to the specialty shops most growers have never heard of, with a note on what each is good for.