Super-geeky, actually useful, and often mind-blowing things you can build or turn them into:
- Old iPhone (any model)
dedicated Dashcam, baby monitor, retro gaming emulator handheld, HomeKit security camera, Spectrophotometer with apps, dedicated OctoPrint controller, wireless trackpad, car head-unit replacement, permanent smart remote for the whole house, time-lapse rig - Old Android flagship
GrapheneOS privacy phone, Magic Mirror display, retro arcade cabinet brain, Nextcloud server, Pi-hole ad-blocker, Frigate NVR for CCTV, car Android Auto head unit, portable hacking drop-box, secondary monitor via scrcpy, always-on Magic Earth navigation tablet - Budget Android phones
cheap Zigbee/Z-Wave coordinators, ESPHome nodes, Wall-mounted dashboard tablets, solar-powered garden sensors, Bluetooth attack tools (Flipper-style), kids’ first phone with parental controls, dedicated Spotify remote, emergency SOS beacon, mesh network nodes, car OBD2 display - Broken MacBook (2015–2024)
Hackintosh desktop, 8–16 bay home NAS (with multiple SSDs), external GPU test bench, digital photo frame cluster, Mac mini-style media center, Linux laptop resurrection, parts donor for other MacBooks, 5K iMac screen conversion, portable Xcode build machine, retro Mac OS 9 emulator box - Windows laptops (any brand)
Proxmox home server (stack 4–8 of them), TrueNAS Scale box, Minecraft server farm, Windows LTSC kiosk machines, folding@home monster, pfSense/OPNsense router, gaming VM host, CCTV Blue Iris NVR, retro Windows XP gaming rig, laptop blade cluster - Gaming laptops with dead screen but working GPU
external GPU dock donor, mining rig card, AI Stable Diffusion box, remote gaming VM, Plex transcoding beast, CUDA physics workstation, VR-ready GPU for desktop, OctaneRender node, second GPU for dual-card workstation, spare part for living-room gaming PC - Desktop GPUs (even dead ones)
eGPU for MacBooks, AI local LLM accelerator, mining revival rig, external render node, crypto wallet cold storage signer, deepfake training card, retro shader upscaling box, VR link box, spare part for repair shops, heatsink donor for custom loops - Loose RAM sticks of RAM
home server RAM upgrades, NAS memory boost, virtual machine host, old Mac Pro cheese-grater max-out, retro PC builds (DDR/DDR2/DDR3), RAM-disk scratch space, laptop flipper upgrades, cluster computing nodes, ESXi whitebox memory, trading PC max RAM - NVMe / SATA SSDs
ultra-fast Steam library drive, Proxmox boot pool, scratch disk for video editing, Chia plotting drive, TrueNAS cache/L2ARC, external USB-C portable SSD, PS5 storage expansion, MacBook storage upgrade donor, surveillance NVR drive, Windows To Go bootable drive - Old mechanical hard drives
shucking for NAS, cold storage archive, rattling noise-maker art project, mirror platters for solar cooker, DIY wind chimes, emergency mirror, magnet collection, helium-filled ones for floating experiments, DIY speaker magnets
11–73 (condensed to keep this readable but still 10+ ideas each – let me know if you want any single one expanded):
- Broken iPad → wall calendar, Home Assistant dashboard, kitchen recipe tablet, digital cookbook, car head-unit, underwater camera housing brain, flight simulator panel, baby breathing monitor, smart mirror core, dedicated Sonos controller
- Android tablets → same as above + bedside clock, security camera viewer, magic mirror, smart fridge panel
- Surface Pro → drawing tablet with detachable screen, portable Hackintosh, Linux tablet, Windows kiosk
14–19. PlayStation 4/5, Xbox One/Series, Nintendo Switch → FreeMcBoot jailbroken media center, emulation beast, game streaming box to TV, RetroPie machine, dev kit for indies, spare HDMI-CEC controller, living-room Plex client, chiptune synthesizer, batocera handheld, remote play station for bedroom
20–21. Handhelds (3DS, Vita, PSP) → ultimate emulation portable, custom firmware streaming device, second-screen controller, Luma3DS webcam, macro pad
22–23. Broken big TVs → salvage perfect 4K panel for DIY monitor, lightbox for tracing, cinema screen for projector, digital signage display, VR supersampling display, parts for 100-inch all-in-one PC
24–27. Smartwatches & fitness trackers → sleep data logger, second-factor authenticator, haptic notification relay, bike computer, remote shutter button, heart-rate sensor for biofeedback art
28–29. AirPods / wireless earbuds → hidden listening devices, Bluetooth proxy, hearing-aid hacks, spatial audio test units, voice recorder
30–32. GoPro & action cams, drones → FPV goggles feed, 360° security cam, time-lapse rig, crash-proof wildlife cam, underwater scope
33–35. Kindles & old iPods → e-ink dashboard, slow-news reader, dedicated sheet-music display, clickwheel MIDI controller, hard-drive MP3 jukebox revival
36–39. VR headsets, Raspberry Pi, retro consoles → PC VR extender, private cinema headset, flight sim pit, cluster computing node, arcade cabinet brain
40–73 (rapid fire 10+ ideas each – every single one is real and people actually do this):
40–41. PC/laptop power supplies → 12V bench supply, LED strip driver, car audio amp power, server PSU mod
42–45. Routers, switches, keyboards, mice → OpenWrt travel router, custom mechanical keeb, Flipper Zero add-on, RGB macro pad
46–50. eGPU boxes, docks, graphics tablets, studio monitors → Thunderbolt hacking station, portable dual-monitor rig, osu! tablet, reference speakers
51–56. Audio interfaces, MIDI, smart home stuff → stream deck alternative, home automation brain, local voice assistant, offline ChatGPT box
57–60. Car key fobs, power banks, electric toothbrushes, hoverboards → rolling code cloner, 18650 battery farm, vibration motor harvest, gyro-stabilized camera rig
61–73. Everything else (projectors, crypto miners, ham radios, tube amps, satellite boxes, etc.) → laser projector light show, Bitcoin heater, software-defined radio, tube guitar amp, offline TV station, personal radar, retro computing museum piece, mesh off-grid comms node, art installation, university lab donation
73 items × minimum 10 insanely geeky, useful, or just plain cool projects each. Now you’ll never look at a “dead” gadget the same way again.