Look here. Pick the one that matches your requirements (filter, or not?). I bet the HIH-5030 series would drop right in to your circuit; check the datasheets. Quantity one price is a bit over half of the price of a HIH-4030 part, and it will work over a wider supply voltage range.
Thanks for the tip. the HIH-5030 is a lot cheaper (can get 2 for the same price as the 4030). Let me check with the customer, and get their go-ahead.
BTW. this Aquarius Smart Control System is made in Cape Town, South Africa.
It consists of a Daylight Sensor module, that interprets the daylight shining on a white dome. (That goes Just outside the greenhouse tunnel)
It has another module that has the Humidity and Temperature Sensors, and that is inside the tunnel.
They communicate to the control module using an RS485 Signal. Both the Sensor Modules, and the Control Modules use Atmel uC.'s
It calculates the energy used by the plants based on the Light Exposure, Temperature, and Humidity. And then when it thinks it is time for a watering, it pulses a relay.
There is a Multizone Irrigation Controller that then picks up this pulse, starts the waterpump and Main Valve. It then Opens each tunnels solenoid valve for a preset period, to water each tunnel.
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