This is Version TWO of the USB PowerControl. Version ONE is here.
Note: If you leave the Grove Connector unconnected, Version Two behaves exactly like Version One.
The USB PowerControl board is a USB to USB solid state relay. It is is a digitally controlled power switch for your Arduino or Raspberry Pi. It is a Pi On and Off switch.
We have now added a Grove Digital Input that allows you to control the USB PowerControlV2 using two GPIO Lines (one enable and one control line) to switch on and off from a Grove Digital Port. The Grove Enable Line, when high, disables the LIPOBATIN line and makes control of the device under the Grove Control Line. When the Grove Enable Line is low, the LIPOBATIN line controls the relay as in the original USB PowerControl. The Grove Enable Line is pulled down by a 43K resistor so if it is disconnected, the USB PowerControlV2 is compatible with the original USB PowerControl.
This circuitry is provided to allow the USB PowerControlV2 to be controlled by either LIPOBATIN or the state of the CONTROL Line (J3 Pin 1). ENABLE (J3 Pin 2) controls whether the USB POWERCONTROLV2 is switched by LIPOBATIN or the CONTROL line. Remember that LIPOBATIN is not a digital input. It is designed to look at the voltage level of the battery.
The truth table for the USB PowerControlNE V2 is given below:
USB PowerControl Application Diagram
Posted by Lutz on Jan 30th 2017
I have tried a number of products that boost power and allow for power shutoff of the consumer device. But they only used their own input voltage as the hysteresis trigger, resulting in lots of flickering and cave-ins. The input for the power control can be taken directly from the battery. And while this may limit the possible runtime of the consumer device (because the power booster could still squeeze a bit more juice out of the battery before the USB current becomes unsustainable) it is giving the consumer device (in this case the SD card of a raspberry pi) a much better chance at avoiding brownouts.
What's not to like? The blue LED is overly bright, and probably consumes a lot of power too.
All prices are in USD.