How do I charge the sensors?
Plug the micro-USB ends of the charging cable into the sensors.
Plug the regular USB end of the charging cable into your personal computer OR into an IEC 60950 approved USB charger.
You may have a charger already; many new mobile phones and other mobile products come with an IEC 60950 compliant USB charger.
Charge the sensors for at least 90 minutes for a full charge.