Scales
Snaptare reads from any USB HID, Bluetooth, or DYMO postal scale via the browser — no native app, no driver, no separate computer. Pair once and the scale auto-reconnects on every shift.
On this page
1. Which scale should I buy?
Three honest answers depending on shop type:
- Bulk grocery / spices / coffee: a DYMO M25 (25 lb / 11 kg) or M10 (10 lb / 4.5 kg) is fine — postal scales were designed for this. ~$60–$100.
- Heavier items (legumes, oats sold by the kilo): a USB POS scale like the Adam Equipment CBC 35a or NCR 9170 — purpose-built retail, more rugged. $200–$400.
- Mobile / pop-up shops: a Bluetooth scale like the Etekcity (consumer-grade) or any retail Bluetooth scale. Pairs over Web Bluetooth, no cables.
2. DYMO USB postal scales (M5, M10, M25)
Filljoy explicitly says DYMO doesn't work. We took it as a marketing brief. Snaptare supports DYMO postal scales over WebHID, the modern browser API for USB HID devices.
Setup:
- Plug the DYMO into the tablet via a USB-C adapter (iPad: Lightning-to-USB-A or USB-C-to-USB-A).
- Open Snaptare → Settings → Scale → Pair.
- Pick "DYMO" from the device picker. Confirm the permission prompt.
- Place a known weight (e.g. a 100 g calibration mass or a litre of water = 1 kg) and verify the reading.
The scale auto-reconnects when you reopen the tablet — you only do this once. Models tested: M5 (5 lb / 2.2 kg), M10 (10 lb / 4.5 kg), M25 (25 lb / 11 kg).
3. Generic USB HID retail scales
Most retail-grade USB scales speak the HID Point-of-Sale Scale protocol (HID Usage Page 0x8D). Snaptare auto-detects and decodes that. Tested:
- Adam Equipment CBC 35a — 35 kg max, 5 g resolution. Pro choice for bulk grain.
- NCR 9170 — common at supermarket checkouts. Heavy, accurate.
- Stamps.com 1AA-PSC10 — postal, lightweight, decent for low-volume tills.
Pairing flow is the same as DYMO: plug in → Settings → Scale → Pair → permission prompt.
4. Bluetooth scales
Web Bluetooth supports any GATT-compliant weight-sensor profile. Snaptare connects via Settings → Scale → Pair (Bluetooth); the OS pairing dialog appears. Once paired, the scale auto-reconnects on app open.
- Bluetooth scales are convenient (no cable) but have higher latency (~200–400 ms vs. USB ~50 ms). Acceptable for most workflows; noticeable on rapid-fire weighing.
- Battery life depends on the scale; LCD-only retail scales last weeks, smart scales with backlit screens last days.
5. iPad vs. Android — what works where
| Capability | iPad (Safari) | Android (Chrome) | Windows tablet (Edge) |
|---|---|---|---|
| USB HID scale (DYMO & co.) | ✓ via USB-C | ✓ | ✓ |
| Bluetooth scale | — (Safari doesn't expose Web Bluetooth) | ✓ | ✓ |
| Voice command | ✓ iPadOS 17+ | ✓ | ✓ |
| Camera (AI tare) | ✓ | ✓ | ✓ |
Bottom line: Android tablets are slightly more capable for full hardware support (Bluetooth scales). iPad is fine for USB HID and is what most shops already have.
6. Calibration & legal-for-trade
Snaptare reads whatever the scale reports. Calibration is the scale's job. Two practical rules:
- Verify with a known weight after pairing (a 100 g or 1 kg calibration mass; or a 1 L bottle of water = 1 kg). The reading should match within the scale's stated resolution.
- Re-verify weekly. Cheap scales drift. The till's anomaly flag will usually catch this for you (see tare §8) — but don't rely on it.
For legal-for-trade compliance (EU "metrology" certification, US NIST Handbook 44), use a certified scale. Snaptare doesn't change the scale's certification — it just reads from it.
7. No scale? Manual entry works
If you're starting out, testing the app, or your scale isn't compatible: type weights on the on-screen number pad. Snaptare assumes grams by default. The till is fully functional without a paired scale.