Fazley RabbiArduino and ESP32 are microcontroller boards: small, low-power chips that run one program to read sensors and switch things on and off. Raspberry Pi is a small computer that runs a full operating system, so it can handle cameras, databases and local dashboards. For a typical connected sensor, the ESP32 is often the practical choice because it has Wi-Fi and Bluetooth built in. Arduino is excellent for learning and simple control. Raspberry Pi suits jobs that need real computing power on site. Many projects use more than one.
Two kinds of board
The most useful distinction is not the brand but the type.
- A microcontroller is like the controller inside a washing machine. It runs a single program, starts the moment it gets power, uses very little energy and keeps doing its job for years. It has little memory, and no screen or operating system.
- A single-board computer is like a small PC. It runs an operating system such as Linux, can run several programs at once, store a lot of data and connect to cameras and screens. It also uses more power, takes time to start and needs a proper shutdown.
Arduino and ESP32 are in the first group. Raspberry Pi is in the second. (The Raspberry Pi Pico is an exception: despite the name, it is a microcontroller board.)
Arduino: the board many people learn on
Arduino is a family of open-source boards together with simple programming tools. It became popular because a beginner can make an LED blink or read a sensor within an hour, and there are countless tutorials and add-on modules.
Classic Arduino boards such as the Uno have no wireless on board, so they need extra modules to connect to the internet. Some newer Arduino models add Wi-Fi. Arduino suits teaching, quick experiments and simple stand-alone control, such as switching a relay when a float switch trips.
The Arduino programming tools also work with many other chips, including the ESP32. So "written in Arduino" often describes the software style, not the board.
ESP32: the workhorse for connected sensors
The ESP32 is a low-cost microcontroller with Wi-Fi and Bluetooth built in on most versions. That one fact explains its popularity in IoT: a single small board can read sensors, apply simple rules and send readings to a server or an MQTT broker without extra parts.
It also has low-power sleep modes, so a battery-powered sensor can sleep most of the time and wake briefly to measure and report. It is a common choice for jobs like a water tank level and pump controller, temperature alerts or energy sub-metering.
Its limits: modest memory, no operating system, and not the right tool for video or heavy analysis.
Raspberry Pi: a small Linux computer
A Raspberry Pi is a credit-card-sized computer. Most current models include Wi-Fi, Bluetooth, USB ports and a display output. Because it runs Linux, it can do things a microcontroller cannot:
- process images from a camera, for example counting items or reading a gauge;
- act as an on-site gateway that collects data from many sensors;
- run a small database or a local dashboard that works without internet;
- run heavier logic at the edge, as explained in edge versus cloud processing.
The trade-offs: higher power use, a longer start-up, and a memory card that can be damaged if the power vanishes suddenly. In places with frequent power cuts, plan a small backup and a clean shutdown.
Side by side
| Arduino (classic) | ESP32 | Raspberry Pi | |
|---|---|---|---|
| Type | Microcontroller | Microcontroller | Small computer |
| Wireless on board | No (some newer models yes) | Wi-Fi and Bluetooth on most versions | Wi-Fi and Bluetooth on most models |
| Power use | Low | Low, very low when sleeping | Higher |
| Start-up | Instant | Instant | Takes a while |
| Cameras, databases, local dashboards | No | Very limited | Yes |
| Best at | Learning, simple control | Connected sensors and controllers | On-site computing and gateways |
Which board for which job
- A temperature or water-level alert over Wi-Fi: ESP32.
- A battery-powered sensor in a pond or field: a low-power microcontroller, often with a LoRa radio, reporting to a gateway.
- A gateway collecting readings from many sensors: Raspberry Pi or similar.
- Camera-based counting or inspection: Raspberry Pi or a more capable computer.
- A classroom demo or a quick proof of idea: Arduino or ESP32, whichever the team knows.
The right choice depends on power, connectivity, the environment and how many units you will build, so treat this list as a starting point rather than a rule.
From prototype board to finished product
Ready-made development boards are ideal for a small pilot. For a product you will install in many places, it often makes sense to design a custom circuit board around the same chip, with a proper enclosure, protected power input and connectors that survive heat, dust and humidity. The article on moving from prototype to product covers that step.
Before choosing, write down what the device must measure, how it gets power, how it connects and what should happen when either fails. The board choice usually becomes obvious. If you want a second opinion, my IoT device development service can help.