# SMASHR bill of materials (batch one, per unit)

Prices are single-unit retail in USD, checked October 2026, to show what a DIY build costs.
Batch one is sourced at volume; the numbers there are lower.

| # | Part | Spec | Qty | Source | Unit USD |
| --- | --- | --- | --- | --- | --- |
| 1 | Controller | Seeed Studio XIAO ESP32S3 (113991114), Wi-Fi 2.4 GHz, USB-C | 1 | Seeed, DigiKey | 7.49 |
| 2 | Button | 100 mm arcade dome with microswitch (Adafruit 1185 red; black cap for the sell unit) | 1 | Adafruit | 9.95 |
| 3 | LED strip | WS2812B, 60 LED/m, 5 V, cut to 24 px (400 mm), coiled in a 127 mm channel | 1 | Generic | 3.00 |
| 4 | Level shifter | 74AHCT125 quad buffer, 3.3 V to 5 V data (Adafruit 1787) | 1 | Adafruit | 1.50 |
| 5 | Resistor | 330 ohm, 1/4 W, in series with LED data | 1 | Generic | 0.05 |
| 6 | Capacitor | 1000 uF, 6.3 V electrolytic across LED 5 V and GND | 1 | Generic | 0.30 |
| 7 | Diffuser | 3 mm frosted polycarbonate ring, laser cut, 120 mm ID / 134 mm OD | 1 | Laser cut | 2.50 |
| 8 | Weight plate | 3 mm mild steel disc, 122 mm, laser cut, zinc plated | 1 | Laser cut | 4.00 |
| 9 | Enclosure | Top shell + base tray, 6061 aluminium, CNC, bead blasted. DIY: PETG print | 1 set | CNC shop | 38.00 |
| 10 | Feet | Silicone bumpers, 12 mm | 4 | Generic | 0.40 |
| 11 | Fasteners | M3 x 8 button head + M3 heat-set inserts | 4 + 4 | Generic | 0.60 |
| 12 | Wire | 22 AWG silicone, red / black / white, 1 m each | 1 set | Generic | 1.20 |
| 13 | Cable | USB-C to USB-C, 1 m, braided | 1 | Generic | 3.00 |

Approximate DIY total with a printed enclosure (about 4 USD of PETG): 39 USD. With CNC aluminium: 73 USD.

## Notes

- The XIAO's onboard 5 V pin passes USB VBUS straight through, so the LED strip draws from USB, not the regulator.
- `LED_MAX_BRIGHT` in `firmware/sendit/config.h` caps brightness at 160 of 255. Full white on all 24 pixels then stays under 1 A.
- The arcade button's built-in lamp is 12 V and stays unwired. The ring does the talking.
- No battery, no screen, no keys. The only secret on the board is the device secret from pairing.