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# Introduction
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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:
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We started with a U.S. Solid Smart Motorized Ball Valve (Model USS-MSV00087). The work with this platform was later suspended due to slow response time, limited distances of operation and overall challenges with the hardware. Initial issues with reliance on an online application, we approached this as a hardware base. After abandoning this hardware, we turned our attention to Edwards' solenoid-style control valves. IPVA10EX 24VDC PN C41770200.
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## Valves
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The valves from Edwards utilize a simple 24vdc control signal to actuate the solenoid valve. Application of power opens the valve quickly (nearly instantaneous). Removal of voltage closes the valve just as quickly. When the system is powered down, the valves cannot open. In addition, the actuation of the valves is much more responsive.
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## Control Signals
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To control the valve operation, a set of relays is employed. The initial hardware is an 8-position relay, though only 4 are implemented in software. The relays are opto-isolated from the control side of the board for safety, though the 24vdc passed to the valves is still considered low voltage (under the 50vdc limit). A micro-controller (described in the next section) controls the relays with a 5vdc signal. The relay board uses an active-low configuration, so an NPN transistor is utilized to further isolate the microcontroller from the relay board. The microcontroller interacts with the base of the transistor, enabling the control pin to go low, enabling the relay.
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# Micro-controller
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Leveraging a [Adafruit QT-PY ESP32-S3 board](https://www.adafruit.com/product/5426) as the new control unit. Pin usage as follows, see image below:
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- A0 - NPN 1 controlling valve 1
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- A1 - NPN 2 controlling valve 2
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- A2 - NPN 3 controlling valve 3
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- A3 - NPN 4 controlling valve 4
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- USB - power from USB fed to the VCC and VDD pins of the relay board
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- GND - common ground for all components
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# Deprecated details related to U.S. Solid hardware
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Reverse engineering was successful with the identification of key components as follows:
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## Motor control
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- [RZ7888](https://www.micros.com.pl/mediaserver/UIRZ7888_0001.pdf) (2A motor control driver IC, SOP-8 package)
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- 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
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