Essential Components

Before you can build anything, you need parts. This article lists the essential components for getting started with ESP32 projects, explains what each one does, and helps you understand what to look for when buying.

🔗Starter kit checklist

Here is everything you need for the projects in this tutorial series:

Links marked Amazon/AliExpress are affiliate links. We may earn a small commission at no extra cost to you.

Total estimated cost: $30-55 (depending on where you buy and whether you choose individual parts or a kit).

You can often find "ESP32 starter kits" that bundle the board with a breadboard, wires, LEDs, and resistors. These can be good value, but check that the kit includes an ESP32-WROOM-32 DevKit and not a different variant.

🔗Component details

🔗ESP32 development board

As discussed in the What Is an ESP32? article, we recommend the ESP32-WROOM-32 DevKit (also sold as ESP32 DevKitC V4, DOIT DevKit V1, or NodeMCU-32S). These boards cost $4-8 and come with everything you need: the ESP32 module, USB port, voltage regulator, boot and reset buttons, and pin headers.

Tip: Buy two boards if your budget allows. They are cheap, and having a spare means you are never stuck if one develops a problem. It also lets you build projects that communicate with each other.

🔗USB cable

Your ESP32 dev board connects to your computer with a USB cable for both programming and power. Check which connector your board has:

• Micro-USB -- Most common on older and budget boards
• USB-C -- Increasingly common on newer boards

Make sure the cable supports data transfer, not just charging. Some cheap cables only carry power and will not let you upload code. If your board does not show up as a COM port on your computer, the cable is often the first thing to check.

🔗Breadboard

A breadboard lets you build circuits without soldering. Components and wires push into holes that are connected in rows underneath.

How a breadboard works:

• The top and bottom rails (usually marked with red + and blue -) run horizontally along the length of the board. These are for power and ground.
• The inner holes are connected in short vertical columns of 5. The center gap separates the two halves.

A half-size breadboard (400 tie points) is enough for most beginner projects. A full-size board (830 tie points) gives you more room for larger circuits.

Tip: The ESP32 DevKit is wide -- on some smaller breadboards, it covers all the pins on one side, leaving no room to connect wires. A full-size breadboard avoids this problem. Alternatively, use two half-size breadboards side by side, or use male-to-female jumper wires connected directly to the board's pins.

🔗Jumper wires

Jumper wires connect components on a breadboard. You need two types:

• Male-to-male (M-M): Both ends have pins. Used for connections on the breadboard.
• Male-to-female (M-F): One pin end, one socket end. Used to connect modules (like sensors with pin headers) to the breadboard or directly to the ESP32.

A set of 20-40 of each type in assorted colors will last a long time. Different colors help you keep track of connections -- a common convention is red for power, black for ground, and other colors for signals.

🔗LEDs

LEDs (Light Emitting Diodes) are the simplest output component. They light up when current flows through them in the correct direction.

Important LED facts:

• LEDs have polarity: the longer leg is positive (anode), the shorter leg is negative (cathode). A flat edge on the housing also marks the cathode.
• LEDs need a current-limiting resistor (typically 220 $\Omega$ from 3.3 V). Without one, the LED will draw too much current and may burn out -- and it could damage your ESP32 GPIO pin.
• Standard 5 mm LEDs in red, green, yellow, and blue are useful for indicators and testing.

🔗Resistors

Resistors limit current and divide voltage. You will use them constantly. The four values in the checklist cover most beginner needs:

Resistors have no polarity -- they work in either direction.

🔗Push buttons

Tactile push buttons (6 mm) are small momentary switches. Press them and they connect; release and they disconnect. They are used for user input -- triggering actions, changing modes, or resetting.

A push button has four pins arranged in a square. The two pins on each side are always connected to each other. Pressing the button connects the two sides together. When placing a button on a breadboard, orient it so it straddles the center gap -- this ensures the two sides are on separate rows.

You will usually connect a button between a GPIO pin and ground, then use an internal or external pull-up resistor so the pin reads HIGH when the button is not pressed and LOW when pressed.

🔗Capacitors

Capacitors store small amounts of electrical energy and release it quickly. In beginner projects, they serve two main roles:

• Decoupling (100 nF / 0.1 $\mu$F ceramic): Placed near a chip's power pins to filter out electrical noise. These smooth out brief voltage dips caused by the chip switching on and off rapidly.
• Smoothing (10 $\mu$F electrolytic or ceramic): Used on power rails to stabilize voltage, especially when motors or relays cause sudden current draws.

Note: Electrolytic capacitors have polarity -- the longer leg is positive, and the negative side is marked with a stripe. Ceramic capacitors have no polarity.

You may not need capacitors for your very first projects, but you will want them on hand as your circuits get more complex.

🔗Multimeter

A multimeter is one of the most important tools you can own. It measures:

• Voltage (V) -- Check that your power rails are 3.3 V or 5 V as expected
• Resistance ($\Omega$) -- Identify unknown resistors, check connections
• Continuity -- Beep when two points are connected (great for finding broken wires or bad solder joints)
• Current (A) -- Measure how much current a circuit draws

A basic digital multimeter for $10-25 is more than sufficient. You do not need an expensive bench meter for hobbyist work.

Tip: When your circuit does not work, the multimeter is the first tool to reach for. Check that power is reaching your components, that ground connections are solid, and that signal voltages are what you expect. Systematic measurement solves problems faster than guessing.

🔗What you do NOT need yet

You might see tutorials recommending additional components. These are useful but not essential to start:

• Soldering iron -- Not needed while you are using a breadboard
• Oscilloscope -- Helpful for debugging signals, but overkill for beginners
• Logic level converter -- Only needed when interfacing with 5 V devices
• External power supply -- USB power is sufficient for most beginner circuits
• Perfboard / PCB -- For permanent projects later, not prototyping

Start with the basics and add tools as your projects demand them.

🔗Next steps

Once you have your components, the next step is setting up the software. The next article walks you through installing and configuring the Arduino IDE so you can start writing code for your ESP32.