The Detector node shall operate on an internal single cell 4.1V LiPo battery. After fully charged, the battery must keep energy so the Detector node keeps running for at least 20 weeks,
Discharge
If the voltage drops below the acceptable level (4.1V LiPo battery must not be undercharged below 3.2V), the device has to switch off itself.
Before the Battery will be discharged to the minimum level, the following actions shall take place:
below 3.6V: warn the user about the low battery level (must happen by sending a dedicated message over TTN)
below 3.4V: switch off power consuming operations (and report this state by sending a dedicated message over TTN):
do not measure PM values anymore, switch off the PM sensor
do not measure Temperature and Relative Humidity anymore, switch off the DHT sensor
Charge
The battery shall be chargeable by using a 5V USB micro connector. An overcharge protection shall avoid battery damage.
Rationale
The Detector node shall be able to operate autonomously at least for 20 weeks without any external power supply.
Safety is important, especially with LiPo batteries.
TechREQ
Description
The Detector node shall operate on an internal single cell 4.1V LiPo battery. After fully charged, the battery must keep energy so the Detector node keeps running for at least 20 weeks,
Discharge If the voltage drops below the acceptable level (4.1V LiPo battery must not be undercharged below 3.2V), the device has to switch off itself.
Before the Battery will be discharged to the minimum level, the following actions shall take place:
Charge The battery shall be chargeable by using a 5V USB micro connector. An overcharge protection shall avoid battery damage.
Rationale
The Detector node shall be able to operate autonomously at least for 20 weeks without any external power supply. Safety is important, especially with LiPo batteries.
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