Fingerprint Sensor AS608 - A Beginner's Guide
One touch can replace keys. This project uses an optical fingerprint sensor to enroll users and then grant access with a quick scan.
read tutorial →
3.7V Polymer Lithium Ion Battery — 40mAh
The Polymer Lithium Ion Battery 3.7V 40mAh is a rechargeable lithium cell with a JST connector, designed for portable electronics, wearables, IoT devices, and maker projects. Pair it with a LiPo charger like the TP4056 or Adafruit Micro Lipo.
Safety: Lithium batteries can be dangerous if punctured, short-circuited, or overcharged. Always use a proper LiPo charger with protection circuitry.
3.7V battery size guide
| Capacity | Best for |
|---|---|
| 105–150 mAh | Tiny wearables, coin-cell replacements |
| 350–500 mAh | GPS trackers, small IoT sensors |
| 850–1200 mAh | Handheld devices, Feather boards |
| 2000–2500 mAh | Phones, tablets, Raspberry Pi portable |
| 4400–6600 mAh | Extended runtime, power banks |
Technical specifications
| Chemistry | Polymer Lithium Ion |
|---|---|
| Voltage | 3.7V nominal |
| Capacity | 40mAh |
| Connector | JST-PH 2-pin |
| Rechargeable | Yes |
Manila stock. Order before 16:00 PHT, ships today via J&T or LBC. Provincial: 1–3 working days.
Schools / class POs: we accept Purchase Orders for accredited schools and universities. contact us with your PO details.
Returns: 7-day inspection window for DOA units. Email proof of issue and we ship a replacement.
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