Hi everyone,
I’m a beginner with Arduino and currently working on a small project. The idea is as follows:
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Use a color sensor to detect the green color of leaves.
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Once the green color is detected, the distance sensor becomes active.
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If the measured distance is less than 0.3m, the Arduino will send an output signal to open the solenoid valve and activate the pump, which will draw water from the tank and spray it through a nozzle.
The main items I currently have are:
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Color sensor
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Distance sensor
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Arduino
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Solenoid valve
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Pump
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Relay
My problem is:
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I don’t know how to properly connect these items together so that they work reliably.
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I’m not sure if I already have all the necessary components, or if I’m missing something important.
I would really appreciate it if someone could guide me on how to connect these items and let me know if I need any additional components to make the system work safely and effectively.
Thanks a lot for your help! 
You will need to add these components to your setup.
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External 12V power supply (for pump + solenoid)
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Flyback diode (1N4007 or similar) across solenoid and pump (to protect electronics from voltage spikes when turning off coils)
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Relay module with optocoupler (if you don’t already have one, this ensures isolation between Arduino and high-power devices)
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MOSFET module (optional) – instead of a relay, MOSFETs are better for pumps/valves because they’re faster and last longer.
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In any project you should create a diagram of what you want to do. Can be simple sketch or complex schematic. Then decide, figure out, how you are going to do it and what devices you will/may need.
Divide the project into separate parts and test each. ie the Arduino, how to program it, how the interfaces work, the limitations it has, the power it needs. The colour sensor, determine what it needs to work, what interface does it use, what power does it need, will it need something between it and the Arduino and how the Arduino will produce results once it is connected.
But it all starts with documentation. Write down what you want to do and how you plan to do it, then test each part of it separately, get each working then combine them together one at a time. And solve any problems that arise.
Simply write down the power needs of the devices you have purchased and what interface they have and how they can be connected to the Arduino and how the software on the Arduino will access them.
Regards
Jim
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From the parcel list; I see you have purchased a 12V plug pack. All the other electronic devices work with 5V.
The Arduino can be powered from a PC USB port. The 5V out of the Arduino can be used to power the colour sensor and the ultrasonic sensor because they consume little power. BUT the relay module needs about 70mA to hold the relay active and there are two of them. You should NOT use the Arduino 5V out to power this. You will need a 5V power supply.
You could use a DC to DC converter like that listed below. Connect 12V from your plug pack as input to the DC to DC convertor. WARNING: The power out of this device is adjustable. DO NOT connect it anything before checking it is set to 5V. The display on the device allows you to check this.
What is the final design for this, will it always be connected to a PC ??
Protection of these delicate electronic devices is important, some sort of case you should also look at.
Cheers
Jim
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Add on to
James46717 reply above
Make sure the “parent” 12V supply will provide the TOTAL current plus a bit for headroom. That is a 12V 500mA supply would probably not be anywhere near enough.
Cheers Bob
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