home.md

+# Introduction
+We started with a U.S. Solid Smart Motorized Ball Valve (Model USS-MSV00087). Due to the reliance on an online application, we approached this as a hardware base. Reverse engineering was successful with the identification of key components as follows:
+## Motor control
+- RZ7888 (2A motor control driver IC, SOP-8 package) 
+- Activation of the close function of the valve via Y1 NPN transistor (noted in purple below) - tied to pin 1 of the motor control and controlled by pin 6 of the control board
+- Activation of the close function of the valve via Y1 NPN transistor (noted in orange below) - tied to pin 2 of the motor control and controlled by pin 5 of the control board
+- Activation of direction is driven by pulling the appropriate pin to low
+- When both pins are high, the motor is frozen in a fixed position (regardless of the torque on the valve
+## Valve position
+- Driven by a multi-turn 10K potentiometer that provide voltage division of the control boards reference voltage (between 3.22-3.31vdc)
+- Higher voltage indicates the valve is more open with full open at the reference voltage
+- Lower voltage indicates the valve is more closed with full closure at 0vdc
+- Originally attached to pin 14 on the control board
+## Valve Position Interrupt
+- Driven by an onboard momentary pushbutton in position K1 on the valve board
+- When pressed, the pin is drawn low
+- Originally attached to pin 13 on the control board
+## Original control chip
+- STC 8H1K08 series in a SOP-20 package
+- In position U4 on the valve board
+- Removed using hotplate and reflow method as to not disturb any other components
+## Original communications chip
+- Model number obscured, but appears to be an ESP8266 or ESP32 compatible chip
+- In position U3 on the valve board
+- Removed using hotplate and reflow method as to not disturb any other components
+
+![IMG_1065](uploads/a8ee2076590dba3169e23a6ae7dc57f1/IMG_1065.jpg)
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