OpenSprinkler Forums Hardware Questions DIY Kit Assembly Questions Connecting Expansion board to Arduino?

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    I was wondering if it would be possible (in an easy manner, aka so a newbie could do it) to use the expansion board and connect it to an Arduino type to test things out (I was thinking using this:

    I thought I could get one of the boards and have an Arduino type plug into the EXTIN jumper but there is something I’m not sure I understand

    When looking at the main board ( I see the power part, but that seems to just convert the 24AC to 5V DC for the PI and circuit if I got this correctly. I”m not sure I understand from the schematic how the 24AC is brought to the valves.

    so to my question:
    – if I get a 24VAC Power supply and a boost converter something like a 24VA to 5V boost converter step down
    => can I just connect VCC 5V from the converter to moteino and the VCC of the extension board? and GND from the power supply to the GND of the ext board?

    would that work?

    thanks in advance for any insight/suggestions you may have



    First, a correction: 24VAC to 5VDC would be called a step down converter, not a boost converter. A boost converter generally means bumping voltage up and not down.

    The short answer to your question is that yes you can connect the expansion board to an arduino. The expansion board consists of the following pins:
    – one VCC (3.3V)
    – two ground pins
    – shift register OE (output enable), DATA, CLK, LATCH
    – expansion board sensing pin

    The expansion board sensing pin is optional, you don’t need to connect it. The other pins need to be connected: one GPIO for each of the shift register pins.

    To connect 24VAC adapter, here is what you should do: connect one wire of 24VAC to ground (share ground), the other to the solenoids’ COMMON (COM) wire. You don’t need a 24VAC to 5VDC converter, if you don’t mind using a separate USB adapter to power your Arduino. The reason OpenSprinkler uses 24VAC to 5VDC converter is to allow a single power supply design. An alternative is to use two separate power supplies: one USB to power Arduino, one 24VAC to power solenoids.



    thank you so much for your reply – I will order an extension board today to try it out! thanks again.

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OpenSprinkler Forums Hardware Questions DIY Kit Assembly Questions Connecting Expansion board to Arduino?