Hardware and IoT glossary

Short definitions of the terms that come up when we design battery-powered devices, cameras and smart-home hardware. Each entry links to the page where we use it in practice. If a term you need is missing, ask us.

AI camera

An AI camera runs an image model on the device itself and sends a result, such as "person at the door" or "pallet missing", instead of a video stream. That saves bandwidth and power, and the images can stay on the device. Small models run on a microcontroller; larger ones need a Linux processor with an accelerator. Tokay Lite is the microcontroller kind, Tokay Pro the Linux kind.

Battery life budget

A battery life budget adds up how much charge a device uses per day: sleep current for most of the day plus short bursts for sensing, processing and radio. Divide the battery capacity in mAh by the daily total and you get days of runtime, before derating for cold and self-discharge. The sleep current usually decides the answer. Our post on battery life for IoT devices works through an example.

Bluetooth Low Energy (BLE)

Bluetooth Low Energy is the low-power version of Bluetooth that phones use to talk to sensors, trackers and wearables. A BLE device can run for months on a coin cell because it sends short packets and sleeps between them. Range is roughly 10–50 m indoors. Most devices use it for setup from a phone app, and many send their data over it too; our energy monitor talks to its app over BLE or Wi-Fi.

Certification (FCC, ISED, CE)

A device with a radio needs certification before it can be sold: FCC in the US, ISED in Canada and CE in Europe. A lab tests radio emissions and safety, and the results are filed under the product's ID. Using a pre-certified radio module cuts the testing, but the finished product still needs its own approval. We plan for it from the first schematic; see our hardware development services.

Deep sleep

Deep sleep is the mode in which a microcontroller switches off its processor, most of its memory and its radio, and keeps only a timer or a wake pin alive. Current drops from tens of milliamps to a few microamps. A battery device spends almost all its life in deep sleep, so the current drawn in this mode decides battery life. Tokay Lite wakes from it on a timer or on motion.

Edge AI

Edge AI means running a machine-learning model on the device that collects the data, rather than sending the data to a cloud server. The device answers in milliseconds, works without a network connection and sends only results. The limits are model size and power: a microcontroller runs small classifiers, a Linux processor with an NPU runs object detection on video. Our post on edge AI features and applications lists common uses.

ESP32-S3

The ESP32-S3 is a microcontroller from Espressif with two cores at up to 240 MHz, Wi-Fi, Bluetooth Low Energy, a camera interface and vector instructions that speed up neural-network maths. It costs a few dollars and is widely used in camera boards and smart-home devices. Its sleep current is low enough for battery products. Tokay Lite is built around it.

Hyperspectral camera

A hyperspectral camera records each pixel in dozens or hundreds of narrow wavelength bands instead of just red, green and blue. Gases, plastics, crops and minerals absorb light at their own wavelengths, so the camera can tell them apart where an ordinary camera sees the same colour. The cameras are expensive and produce large files. Our post on hyperspectral cameras in methane detection explains one use.

Indoor asset tracking

Indoor asset tracking finds the location of tools, equipment or stock inside a building, where GPS does not work. Tags send BLE or ultra-wideband signals to fixed receivers, which estimate position to within a room or a few metres. Some systems use cameras or RFID gates instead. What indoor asset tracking is covers the options and costs.

IP rating (IP67, IP68)

An IP rating states how well an enclosure keeps out dust and water. The first digit covers solids (6 means dust-tight), the second covers water: 7 means immersion to 1 m for 30 minutes, 8 means continuous immersion under conditions the maker states. Seals, cable glands and the venting of pressure changes decide whether a design passes. Our solar waterproof camera is sealed to IP68.

IR night vision

IR night vision lights the scene with infrared LEDs, usually at 850 or 940 nm, which the camera sensor sees and people mostly do not. The camera must have no IR-cut filter, or one it can switch out at night, and the image is in black and white. Range depends on LED power, which costs battery. Tokay Lite has onboard IR LEDs.

Local control

Local control means a smart-home device takes commands over your own network, without a round trip to the manufacturer's cloud. Switches respond faster, keep working when the internet is down and do not depend on the vendor keeping its servers running. Tuya devices are cloud-first by default; a local Tuya gateway gives them local control and connects them to Home Assistant.

Low-power microcontroller (MCU)

A low-power microcontroller is a single chip with a processor, memory and peripherals, designed to draw microamps when idle. Low-power parts are judged by sleep current, wake-up time and current per MHz when running. Many add a radio on the same chip. Our overview of wireless low-power MCUs compares the main families from Nordic, Silicon Labs, TI, Espressif and others.

Machine vision camera

A machine vision camera is an industrial camera built to feed images to software that inspects, measures or counts. It has a fixed lens mount, a global shutter for moving parts, a trigger input and a standard interface such as GigE or USB3. It usually sends frames to a PC; a smart camera runs the analysis itself. Read what machine vision cameras are used for.

MQTT

MQTT is a lightweight publish–subscribe protocol for IoT devices. A device publishes short messages to a topic on a broker, and any app subscribed to that topic receives them. It works well on slow or unreliable links because the overhead is a few bytes per message. Tokay Lite and the Tuya gateway both speak MQTT, and Rainforest IoT can receive it.

NPU (neural processing unit)

An NPU is a block in a processor built for the matrix maths of neural networks. It runs an image model many times faster than the main CPU cores and at a fraction of the power. Models usually have to be converted to 8-bit integers to use it. The NXP i.MX 8M Plus in Tokay Pro has an NPU rated at 2.3 TOPS.

OTA update

An over-the-air (OTA) update installs new firmware on a device through its radio connection, without anyone opening the case. A safe OTA design keeps two firmware slots, checks the signature of the download and rolls back if the new version fails to start. Devices that will be in the field for years need it from the first release. We build it into the firmware as part of our hardware development services.

PCB design

PCB design is the work of turning a circuit into a manufacturable printed circuit board: the schematic, the choice of parts, then the layout of copper traces across the board's layers. Layout decides radio range, noise, heat and whether a factory can assemble the board cheaply. Most products go through two to four board revisions before production. We do it in KiCad and Altium; see our services.

PIR motion sensor

A passive infrared (PIR) sensor detects motion by sensing changes in the heat radiated by people and animals as they cross its field of view. It draws a few microamps, so a battery camera can sleep until the PIR wakes it. It does not see through glass and can be triggered by sun-warmed surfaces. Tokay Lite uses one to wake on motion.

PSRAM

PSRAM is external memory that a microcontroller adds over a fast serial bus when its internal RAM is too small. A camera frame or an image model rarely fits in a few hundred kilobytes, so camera boards add several megabytes. PSRAM is slower than internal RAM and draws current while powered. Tokay Lite has 8 MB of PSRAM next to the ESP32-S3's 512 kB of internal RAM.

Real-time clock (RTC)

A real-time clock is a small timekeeping circuit that runs from a few hundred nanoamps while the rest of the device is off. It keeps the date and time and can raise an alarm that wakes the main processor at a set moment, for example to take a photo every hour. An external RTC usually draws less current than a microcontroller's own timer. Tokay Lite has one.

TensorFlow Lite Micro

TensorFlow Lite Micro is Google's runtime for running small neural networks on microcontrollers with no operating system and a few hundred kilobytes of RAM. You train a model in TensorFlow, quantize it to 8-bit integers and compile it into the firmware. It suits keyword spotting, simple image classification and sensor anomaly detection. Tokay Lite supports it alongside Espressif's esp-dl.

Tuya

Tuya is a Chinese IoT platform company whose Wi-Fi and Zigbee modules sit inside thousands of smart-home products sold under other brands. The devices pair through the Tuya Smart or Smart Life app and are controlled through Tuya's cloud by default. A Tuya device on your network is usually one of these white-label products. Our overview of Tuya gateways covers the hardware.

Zigbee

Zigbee is a low-power mesh radio protocol for smart-home sensors, bulbs and switches. Mains-powered devices relay messages for the others, so the network covers a house without Wi-Fi in every room, and battery sensors last a year or more on a coin cell. Zigbee devices need a gateway to reach your network or a phone. A Tuya gateway is one such hub.