Build an Always-On Raspberry Pi Zero W Project: 24/7 FM Radio and More

The Raspberry Pi Zero W Starter Kit remains the cheapest always-on hobbyist computer in 2026 — about $20 for the board alone, $30-40 with a kit. It is not powerful. It does not run anything resembling modern Linux performance. But for a 24/7 always-on project that just needs to sit on the shelf and do one thing well, it is still the right answer. This is the practical guide.

Why the Pi Zero W still wins for always-on projects

Three reasons:

1. Power draw: ~120 mA at idle, ~250 mA under typical hobbyist load. Sub-1W. Runs on a USB phone charger or a small solar setup.
2. Form factor: Smaller than a credit card, fits inside almost anything you can 3D-print.
3. The original Raspberry Pi Zero W product page still lists it — Pi has kept it in production despite the Zero 2 W's existence, because the use case is real.

The Pi Zero 2 W is faster but pulls more power. For always-on projects, the slower-but-cheaper-and-cooler original is the better fit.

Key takeaways

• A Pi Zero W kit + a microSD card from a CompactFlash sibling line-class budget (~$15) + a SATA SSD for backups on your dev workstation is the full hardware story for most projects.
• FM radio (PiFmRds), environmental monitor (DHT22/BME280), bird-feeder camera, household weather station, network ad-blocker — all run fine.
• Use Adafruit's tutorials and Hackster.io's project gallery as the canonical recipe sources.

Project #1: 24/7 FM radio transmitter (low power, your own house)

The PiFmRds project turns a Pi Zero W into an FM transmitter on a chosen frequency. It is not legal at any meaningful power level in most countries — but at the few microwatts the GPIO pin actually produces, it covers maybe 10-20 meters indoors, which is enough to send audio from a server room or shed to your living room. Check your local rules.

Setup:

sudo apt install git build-essential
git clone https://github.com/ChristopheJacquet/PiFmRds.git
cd PiFmRds/src
make
sudo ./pi_fm_rds -freq 107.9 -audio your-audio.wav

A short wire on GPIO 4 acts as the antenna; ~30 cm is plenty. Loop a podcast playlist, an audio book, or whatever you want broadcasting in your house. Set up systemd to autostart on boot and it is genuinely always-on.

Project #2: Household environmental monitor

Pi Zero W + a DHT22 (temperature/humidity) or BME280 (temperature/humidity/pressure) sensor + a small OLED for local display.

• BME280 is I2C — 4 wires to the Pi (VCC, GND, SDA, SCL).
• Log readings every 5 minutes to a local SQLite file.
• Expose a tiny Flask endpoint over the LAN; pull readings into Home Assistant.

Power: 24/7 from a USB wall wart. No fan, no moving parts. Will run for years if the SD card holds up — which leads to:

The SD-card-failure problem (and how to dodge it)

Pi Zero W's storage is microSD. SD cards in always-on roles fail. Mitigations:

1. Mount the root filesystem read-only. Use overlayfs for writes. Most "appliance" Pi setups do this.
2. Log to RAM (tmpfs) and rsync to a real disk hourly.
3. Keep a backup image on a SATA SSD like the Crucial BX500 1TB on your workstation. Re-flash from backup when an SD inevitably dies.
4. Archive critical state to a CompactFlash card as belt-and-suspenders (Transcend CF 4GB is fine for low-frequency state archive — yes it is an old format, but a CF card on a USB reader is the most-shelf-life storage you can hand-mount).

Project #3: Network ad-blocker (Pi-hole)

Pi-hole on a Pi Zero W is the canonical always-on Pi project. Block DNS-level ads for the whole home network. The Zero W is enough for a 5-10 device household; for bigger networks, step up to a Pi Zero 2 W or a Pi 4.

Setup is curl -sSL https://install.pi-hole.net | bash. Point your router's DNS at the Pi. Done. Roughly 80% reduction in ad traffic, household-wide.

Project #4: Bird-feeder camera

Pi Zero W + Pi Camera Module 2 + a 3D-printed bird-feeder mount. Snap pictures on motion (via a PIR sensor or via OpenCV motion detection), upload to a folder, browse later. Pi Zero W struggles with realtime video encoding above 720p; for stills, it is fine.

Power needs are higher here — budget for a 2.5A wall plug or a small solar+battery setup if outdoors.

Project #5: Sensor relay over LoRa or BLE

Pi Zero W + a HopeRF LoRa hat + a battery. Acts as a relay between remote sensors (rain gauge, mailbox sensor, garage door state) and a home Wi-Fi network. Pi Zero W's BLE radio is the cheap path; a LoRa hat ($25-30) is the long-range path.

What the Pi Zero W cannot do

• Anything CPU-heavy. The single-core ARM11 at 1 GHz is slow. Don't try to run anything you would call "modern".
• Realtime video at >720p. Don't try.
• More than one or two heavy projects on the same Pi. One job per Pi is the right pattern. Buy three Pi Zero Ws for $60 and avoid the temptation to put everything on one.
• Local LLM inference. Even Q2 tiny models choke. Use a Pi 5 16GB or step up to a desktop rig.

Common pitfalls

1. Cheap power supplies. Pi Zero W is famously sensitive to undervoltage. Use a 2A+ supply, not the random one from your drawer.
2. Skimping on the microSD. A1-rated cards last; cheap unlabeled cards die in weeks under writes.
3. Mounting it outside without protection. A IP65 enclosure is a $10 investment that saves $30 worth of Pi.
4. Forgetting to disable HDMI and the LEDs to save power. tvservice -o and the boot-config tweaks save 30-50 mA — meaningful on solar.
5. Trying to compile heavy software on-board. Cross-compile or use a faster Pi for builds, then deploy the binary.

A worked example: weekend FM-radio build

Saturday morning:

• Flash Raspberry Pi OS Lite onto a 16GB microSD.
• Boot, set up Wi-Fi via the headless config.
• Install PiFmRds (above).
• Set up a systemd service that loops a podcast directory.
• Solder a 30cm wire to GPIO 4.
• Mount in a small box, plug into a USB charger in the basement.

Sunday: walk through the house with a portable FM radio and confirm the signal carries from basement to living room. Total build cost: ~$35 in parts. Always-on hobbyist project, running by Sunday evening.

Pi Zero W vs Pi Zero 2 W vs Pi 5 — pick the right tier

The Zero W's price advantage is meaningful: a $20 board lets you spread workloads across multiple physically-separated devices, which is a better reliability story than one Pi 5 doing everything.

Networking and remote access

Pi Zero W's Wi-Fi is single-band 2.4 GHz only. For most always-on projects this is fine — Wi-Fi 2.4 reaches further and through more walls than 5 GHz. If your house is dense with 2.4 GHz traffic, expect throughput around 5-10 Mbps real-world. Plan accordingly: if your project streams more than that (a camera, an audio relay), put it on a Pi 4 or Pi 5 with 5 GHz.

For remote SSH access, use Tailscale on the Pi side. Avoids port-forwards, works through CGNAT, and the Zero W has enough headroom to run the Tailscale agent without breaking a sweat (~30 MB RAM).

A second worked example: garage-door sensor

• Reed switch on the garage door, wired to a Pi Zero W GPIO pin.
• Tiny Python script polls the pin every 500 ms.
• Open state lasting >5 minutes pushes a notification via ntfy.sh to your phone.
• Tailscale tunnel for remote monitoring.

Total parts: $25 in Pi + microSD + reed switch + jumper wire. Setup: one Saturday afternoon. Has saved one (1) cold-night-garage-left-open in the year it has been running.

Bottom line

In 2026, the Raspberry Pi Zero W Starter Kit is still the right pick for always-on, sub-1W, one-job hobbyist projects. Pair with a reasonable A1-rated microSD, mount it sensibly, and keep a backup image on a SATA SSD on your dev workstation. For long-shelf-life state archive, keep a CompactFlash card in a USB reader as a paranoid second backup. Then build the small thing that does the one job well.

Related guides

• PebbleOS Comes to the Raspberry Pi RP2350
• Raspberry Pi 5 16GB for Local LLMs

Citations and sources

• Raspberry Pi — Pi Zero W product page
• Adafruit — tutorials
• Hackster.io — project gallery

This piece is editorial synthesis based on publicly available information. No independent first-party benchmarking is reported.