Usually you add the transistor to flip the polarity of the signal, ie, you want active to be high instead (or whatever it is).? That usually means you bought the wrong sensor.

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The 200mA would be referring to how much load the sensor can handle when active, that’s for when you want to switch a relay or something directly from it.? Adding a transistor in that case makes sense if the relay draws more that 200mA, for the logic high/low a Gecko needs it doesn’t matter.

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The Geckos have opto-isolated inputs (IIRC) and they need a bit more current that a straight I/O pin, but probably under 10mA.

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Without knowing what sensor you have, 7.5v sounds a bit low.? Yeah the spec sheet says it’ll run at that, but I’ve found the higher the voltage the better.? Most go up to 36v.? The Gecko should have a 12v output for sensors, run it off that.? Running it from the same power supply tends to make things happier.

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Tony

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