Parts List for DIY Smart Home Builds: Arduino + Pi Starter Kit

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Every Arduino and Raspberry Pi smart home build starts with the same shopping list. Buy these components in one order, store them in a parts box, and the next 20 projects don't require a 48-hour Amazon delivery to start. The complete starter kit costs about 75 GBP plus the Pi 5 itself.

I built up my parts box gradually over three years and ended up paying twice as much as a planned upfront order would have cost. The list below is what I'd buy on day one if starting over. It covers the components needed for the first 20 projects without per-project sourcing trips.

The Three Boards Every Smart Home Builder Wants

Three Arduino-class boards cover most projects in 2026:

• ESP8266 D1 Mini at about 4 GBP each. The cheap workhorse for WiFi-only sensors. Buy 3-4 for a starter stash.
• ESP32 DevKit at about 6 GBP each. WiFi plus Bluetooth, dual-core, more pins. Buy 1-2 for projects needing Bluetooth or more processing.
• Arduino UNO R4 WiFi at about 20 GBP. Beginner-friendly with native USB and 5V tolerance. Optional but worth having for tutorials that assume Arduino IDE.

Plus the central brain:

• Raspberry Pi 5 with 8 GB RAM at about 85 GBP. The hub running Home Assistant.

Total board investment: roughly 110-130 GBP. This single purchase opens up the entire DIY smart home category.

Breadboards and Jumper Wires

Every project except the smallest uses a breadboard. The standard sizes:

The 830-point full-size breadboard handles complex multi-sensor projects with two ESP boards or one ESP plus several sensors. Costs about 4 GBP. Buy 2-3.

The 170-point mini breadboard is for single-sensor builds where the full board would be overkill. Costs about 2 GBP. Buy 4-5 because they're small enough to leave inside finished projects.

Jumper wires come in three pin combinations: male-to-male, male-to-female, female-to-female. A bundle of 120 wires (40 of each type) costs about 3 GBP and handles dozens of projects. Buy two bundles.

Add a small pack of solid-core 22 AWG hookup wire (about 5 GBP) for cleaner permanent installations once you outgrow jumpers.

Sensor Starter Pack

The sensors that cover 80% of beginner smart home projects:

DHT22 temperature and humidity sensors at about 4 GBP each. Buy 3 for parallel projects.

BMP280 pressure and temperature sensors at about 3 GBP each. Buy 2.

HC-SR501 PIR motion sensors at about 3 GBP each. Buy 2.

Reed switches with magnets at about 50p each. Buy 4-5 for door/window projects.

Light-dependent resistors (LDRs) for ambient light at about 30p each. Buy 5.

Capacitive soil moisture sensors at about 4 GBP each. Buy 2.

DS18B20 waterproof temperature probes at about 3 GBP each. Buy 2 for outdoor or wet-environment projects.

Total sensor kit: about 30 GBP. Covers nearly every starter project from the Arduino hardware reference examples without per-project sensor sourcing.

Power Supplies (The Bit Beginners Skimp On)

Quality power is the single most underrated component in DIY smart home builds. Cheap phone chargers cause sensor instability, random reboots, and SD card corruption on the Pi. The right kit:

For ESP boards: USB-C 5V 2A supplies at about 8 GBP each. The Mean Well GS09U-USB-C is the reliable choice. Buy 2-3.

For barrel-jack devices: 12V 1A regulated supplies at about 8 GBP each. Standard 5.5mm centre-positive barrel. Buy 2.

For the Raspberry Pi 5: the official Pi 5 power supply at 15 GBP. Don't use generic chargers -- the Pi 5 has specific 5V 5A current requirements that cheap adapters fail to meet, causing throttling and corruption.

For battery-powered projects: 18650 lithium cells (about 3 GBP each from reputable brands like Samsung or Sanyo, avoid no-brand) plus a TP4056 charging module (about 1 GBP each).

Skip USB-A power because newer boards use USB-C and the adapter mess is not worth saving the 50p per cable.

Resistors and Capacitors

The boring components beginners always forget:

Resistor starter pack with 100x each of 220Ω, 470Ω, 1kΩ, 4.7kΩ, 10kΩ, 100kΩ. Cost about 3 GBP. The 220Ω resistors are LED current limiters; 4.7kΩ are I2C pullups; 10kΩ are general-purpose pullups.

Ceramic capacitors: 100nF (0.1uF) decoupling caps in packs of 20 at about 1 GBP. Place across the power and ground pins of every sensor to reduce noise.

Electrolytic capacitors: 100uF and 470uF for power filtering at about 2 GBP for a small pack.

These components cost almost nothing individually but solve recurring noise and stability problems that look mysterious without them.

Storage and Connectivity

The Pi's storage and network components:

microSD card: SanDisk High Endurance or Samsung Pro Endurance 64 GB at about 15 GBP. The "high endurance" rating matters because Home Assistant writes constantly. Generic cards die within 6-12 months.

NVMe SSD via PCIe HAT for the Pi 5: about 55 GBP for a 256 GB SSD plus 25 GBP for the HAT. Massive reliability and performance improvement over SD card. Worth the upgrade after the first six months.

USB-C data cables: 1m length, properly rated. About 3 GBP each. Buy 3-4 to avoid the dance of moving the same cable around.

Ethernet patch cable: 1m Cat 6 at about 3 GBP. The Pi is more reliable on wired ethernet than WiFi. Run cable if at all feasible.

Enclosures

Three categories of enclosure for finished projects:

3D-printed PLA cases at about 50p of filament each, if you own a printer. The Bambu Lab A1 at 250 GBP pays back in cases alone if you build more than 10 projects per year. Thingiverse has thousands of ready-made designs for ESP32 and ESP8266 enclosures.

Generic project boxes from electronics suppliers at about 3-8 GBP each. Less elegant than custom 3D prints but available immediately without a printer.

Recycled containers (Tic Tac boxes, old phone cases, broken USB chargers gutted of electronics) for prototype enclosures. Free and surprisingly effective.

For outdoor or damp environments: IP65-rated plastic project boxes at about 10-15 GBP each. Worth the premium for any sensor exposed to weather.

Essential Tools

Five tools that survive long-term in my workshop:

Pinecil V2 USB-C soldering iron at about 30 GBP. The portable temperature-controlled iron that beats every cheap fixed-temp iron and competes with bench irons twice the price.

Multimeter: Aneng AN8009 at about 25 GBP. Good enough accuracy for hobby use without spending Fluke-level money.

Wire strippers and side cutters: a quality pair from Knipex or Hozan at about 20 GBP for the pair. Cheap tools chew up the wire and damage components.

Helping hands magnifier with two crocodile clips: about 15 GBP. Holds work while you solder. Essential.

Anti-static mat: about 10 GBP. ESP32 boards are sensitive to static; one accidental zap kills them silently. The mat plus a wrist strap prevents most static damage.

Total tool kit: about 100 GBP for a setup that lasts a decade. The Raspberry Pi accessories ecosystem and electronics suppliers like Pimoroni stock similar items at competitive prices.

What I Wish I'd Skipped Buying

For honesty, three categories of purchase that were waste of money:

The first is exotic sensors I bought "just in case". An ultrasonic distance sensor I've never used. A 9-axis IMU board that sat in a drawer. A heart-rate sensor that worked badly. Buy sensors when you have a project that needs them, not because they look interesting.

The second is cheap unbranded boards under 3 GBP. The pin headers were misaligned, the silkscreen was wrong, the regulators got too hot. Stick to branded boards (Wemos, Espressif) even when the AliExpress clones look identical.

The third is starter kits with 200+ components from no-name brands. Half the components were in unlabelled bags and I never figured out what they were. Branded kits from Elegoo or Freenove cost slightly more but the components are labelled and the documentation is real.

A 75 GBP Day-One Order

For someone starting today, this is the exact order I'd place. Excludes the Pi 5 which is a separate purchase.

Two ESP8266 D1 Mini boards (8 GBP). One ESP32 DevKit (6 GBP). One 830-point breadboard (4 GBP). 120-wire jumper bundle (3 GBP). Three DHT22 sensors (12 GBP). Two HC-SR501 PIR sensors (6 GBP). Two reed switches with magnets (1 GBP). Two capacitive soil moisture sensors (4 GBP). Three USB-C 5V 2A power supplies (24 GBP). Resistor starter kit (3 GBP). Four project enclosures (10 GBP).

Total: 81 GBP. Slightly above the 75 GBP headline but covers the first dozen projects without any further sourcing trip.

Add the Pi 5 8 GB at 85 GBP plus official PSU at 15 GBP plus 64 GB SanDisk High Endurance microSD at 15 GBP for the central brain. Combined Arduino-plus-Pi starter cost: about 196 GBP all in.

That's the floor for a serious DIY smart home build. It looks like a lot of money on the order summary, but spread across 50+ sensors and years of use the per-project cost is trivial. The bigger investment is the time to learn, not the components themselves.

The parts box approach beats per-project sourcing because the lead time on Amazon Prime delivery destroys momentum. The moment you have an idea for a sensor project at 9 PM on a Friday, having the parts in a drawer turns "I'll order it tomorrow" into "I'll build it now". That difference -- start now versus wait until parts arrive -- is what separates active builders from people who keep planning to start.