Bill of materials
One wand, one sitting
Prototype cost at onesy-twosy pricing. The timber is the soul; the XIAO is the only board that earns its keep. Everything else is there because the envelope demanded it.
Parts (ones)
$50
unassembled kit
Play draw
26 mA
mixed laser + SFX
Session
3.2 h
150 mAh pouch
| Ref | Part | Source | Each | Note |
|---|---|---|---|---|
| U1 | Seeed XIAO nRF52840 Sense Cortex | Seeed / Digi-Key | $15.40 | MCU, BLE, IMU, mic, charger |
| DS1 | 650 nm 5 mW laser barrel + driver Laser | Quarton / generic | $4.20 | Cap in firmware to Class 2 |
| LS1 | 13 mm 8 Ω 0.5 W mylar speaker Voice | CUI CSS-13108 | $2.10 | Port under the wrap |
| U2 | MAX98357A I2S Class-D amp Voice | Adafruit / Analog | $2.80 | 10 × 10 mm daughter |
| U3 | Si7210 I2C Hall sensor Magnetic | Skyworks | $1.40 | Dock + token detect |
| MAG1 | N52 NdFeB ring 8 × 3 × 2 mm Magnetic | K&J / local | $0.60 | Around laser barrel |
| BT1 | LiPo 3.7 V 150 mAh w/ PCM Cell | Adafruit 1317-class | $4.50 | Kapton wrap, pommel service |
| J1 | Magnetic pogo pair + dock magnet Cell | SparkFun / generic | $3.20 | 5 V charge, polarity keyed |
| L1 | NFC coil, 2 turns 30 AWG Access | Hand-wound | $0.40 | Under split mid ferrule |
| U4 | LRA haptic 8 mm (optional) Magnetic | Vybronics | $2.60 | Fake 'pull' in pommel |
| Q1 | N-MOSFET laser switch + cap Laser | 2N7002 / AO3400 | $0.35 | Never GPIO-drive the diode |
| MECH | Oak blank, ferrules, crystal, wrap Cortex | Turning / craft | $12.00 | The object, not the circuit |
| Kit total | $49.55 | |||
Power budget
Idle is docked or pocketed. Play is IMU + BLE at 60 Hz with laser at 10% duty and short SFX. Peak is not a number you average — it is the MOSFET and the cell C-rate you size for.