SmartBook

My son LOVES to read, he picked out four books from his bookfair yesterday. He is only 10 mos old though and I want his interests in reading to continue so I decided that I want to make him a smart book that he can read and learn with!

I want to construct his book with wood and acrylic pages, binded somehow using 3D modeling. each page will be interactive and a way to teach my son another skill.

📖 The Book Structure

Binding: 3D print a spine with barrel hinges or Chicago screws through holes in each page — this lets pages rotate open like a real book and is completely replaceable if a page needs swapping out. Print the cover with a slight lip to protect the pages.

Pages: Baltic birch plywood (laser cut) as the base, with acrylic overlays (also laser cut) laminated on top for color and shine. Edges should be rounded and sanded smooth.

Page Size: ~6" × 6" is perfect for small hands — chunky and grippable.

Page 1 (texture garden) uses 3 independent MPR121 channels — one per texture zone — so every patch of the page has its own voice and LED color. Touching all 3 at once unlocks a hidden "garden" sound.

Page 2 (shape window) puts an LED directly behind each acrylic backer so the shape glows its own color when touched. The audio says both the shape name and color name, doubling the lesson per interaction.

Page 3 (rainbow spinner) is the most satisfying — a Hall effect sensor on the fixed page body reads a magnet on the spinning wheel rim. Spin fast and the LEDs chase fast. Let it slow to a stop and it names whichever color segment is at the top.

Page 4 (soft and hard) uses two touch zones with intentionally different LED temperatures — warm white for hard, cool blue for soft — so the light reinforces the concept. Touching both sides simultaneously triggers an "opposites!" bonus clip.

Page 5 (counting shapes) sequences the LEDs to count — 1 flash, then 2 flashes, then 3 — so the lights physically count along with the audio. Touch all 3 rows in order and it runs a full "1, 2, 3!" counting sequence.

Page 6 (shape sort) is the cleverest — IR break-beam sensors sit inside each well so the book knows when a piece has been placed. Fill all 3 wells and the whole book erupts in a rainbow LED sweep and a fanfare. The grand finale every time.

Touch sensing — One MPR121 capacitive touch IC handles all 6 pages over a single I2C bus. The MPR121 has 12 channels, so you have room to add sub-zones per page later (e.g. different spots on the texture garden triggering different sounds). Route a copper tape electrode through the spine's wiring channel to each page.

LEDs — WS2812B addressable LEDs are perfect here. Two short strips (3 pages each) run off separate data pins so you can light up any page independently. Embed them in a routed channel around the page edge or behind the acrylic — the translucent pages will glow beautifully.

Audio — The MAX98357A is a tiny I2S amp (~$1.50) that takes digital audio straight from the Photon 2 and drives a small 3W speaker housed in the spine. Store .wav files on an 8MB SPI flash chip soldered next to the Photon — plenty of room for 50+ sound clips at good quality.

Power — A 2000mAh LiPo with a USB-C charging board keeps it rechargeable. At typical baby-play duty cycles you'd get 6–8 hours per charge. The battery, Photon, amp, and flash all live inside the 3D-printed spine housing.

spine with the barrel hinge system:

firmware logic :

phase 1:

• Sketch final page layouts and dimensions (6" × 6" target)design
• Design 3D spine model in CAD (Fusion 360 / OpenSCAD) — two-half clamp styledesign
• Design page hole positions to match spine barrel hinge slotsdesign
• Plan copper tape electrode routing paths for each pagedesign
• Order all materials: Baltic birch ply, cast acrylic, TPU filament, PETG filamentdesign
• Order electronics: Photon 2, MPR121, WS2812B, MAX98357A, Hall sensor, IR break-beams, LiPo + charger, SPI flash

phase 2:

• Test-cut one page in cardboard to verify hole positions and dimensionsfabricate
• Laser-cut all 6 pages from 6mm Baltic birch — include wire routing channelsfabricate
• Laser-cut acrylic shape backers for page 2 (red, blue, yellow)fabricate
• Laser-cut amber acrylic overlay for page 6fabricate
• Sand all pages to 220 grit, round all edgesfabricate
• Apply food-safe beeswax finish to all wood surfacesfabricate
• 3D print spine (PETG, two halves) — test hinge fit before full printfabricate
• 3D print textured elements: silk flower (silk PLA), TPU leaf pad, bark patch (wood-fill PLA)fabricate
• 3D print raised shape borders for page 2 and shape domes for page 5fabricate
• 3D print shape sort pieces for page 6 (2"+ in size)fabricate
• 3D print color spinner wheel for page 3

phase 3

• Breadboard test: Photon 2 + single MPR121 channel reading a copper tape touch padelectronics
• Breadboard test: Photon 2 + WS2812B strip lighting a single LED on touchelectronics
• Breadboard test: Photon 2 + MAX98357A playing a WAV from SPI flashelectronics
• Test Hall effect sensor detecting spinner magnet rotation on page 3electronics
• Test IR break-beam sensors triggering on shape piece placement (page 6)electronics
• Solder Photon 2 onto carrier board with all peripheral headerselectronics
• Solder LiPo + USB-C charge circuitelectronics
• Apply copper tape electrodes to all pages — test capacitance with multimeterelectronics
• Route thin wire from each page electrode through spine wiring channelelectronics
• Mount WS2812B LED strips in routed edge channels on each pageelectronics
• Mount Hall sensor on page 3 body, glue magnet to spinner rimelectronics
• Mount IR emitter + receiver inside each shape well on page 6

phase 4:

• Set up Particle Workbench in VS Code, create new Photon 2 projectfirmware
• Record or download all audio clips (WAV, 22kHz mono) and load onto SPI flashfirmware
• Write MPR121 I2C init and touch interrupt handlerfirmware
• Write WS2812B LED animation functions (pulse, chase, burst, rainbow)firmware
• Write MAX98357A I2S audio playback from SPI flashfirmware
• Write per-page response logic (touch → LED + audio for each channel)firmware
• Write Hall effect spin detection + LED chase rate mapping (page 3)firmware
• Write IR sensor placement detection + completion logic (page 6)firmware
• Write bonus interaction logic (multi-zone touches, all-wells-filled fanfare)firmware
• Flash firmware and test each page in isolation on breadboardfirmware
• OTA update test via Particle Cloud — confirm remote flash works

phase 5

• Glue 3D-printed textured elements onto page 1 — cure fully before handlingassembly
• Epoxy acrylic backers into page 2 cutouts from behind — check light sealassembly
• Mount spinner axle and test free rotation — ensure no sharp protrusionsassembly
• Inset TPU soft pad flush into page 4 routed pocketassembly
• Glue shape sort wells and tether pieces with short paracord (choke safety)assembly
• Run all wires through spine channel — secure with cable tiesassembly
• Assemble spine halves around wires — test all page hinges rotate freelyassembly
• Mount electronics board + LiPo inside spine cavityassembly
• Full system test: every page, every touch zone, every LED and audio responseassembly
• Safety check: no sharp edges, no loose pieces over 1.25", no exposed wireassembly
• Apply final beeswax coat to any bare wood exposed during assemblyassembly
• Charge fully and do a 30-min play test