Arduino Pull-up Resistor

Hey guys,

So this coin acceptor I am trying to program has been giving me problems. I emailed the manufacturer and they told me I needed a 10k ohm pull-up resistor between the signal wire of the coin acceptor and the arduino. I am in a big rush as this is for a project and I cant seem to find any online that will come in a few days. Will a regular 10k ohm resistor work the same? Any other alternatives to the pullup resistor I could use? Or does anyone know any fast shipping sites that carry them?

pinMode (pin, INPUT_PULLUP) is worth trying,

A pullup resistor isn't a special kind of resistor, its what its used for.

As MarkT said the description "pull up" is a usage description. Similar to "rear tire" its still a tire but used in the rear.

FYI the input to you coin acceptor (CA) is likely the solid state equivalent to a switch to ground. If you put a volt meter on the CA lead you will read 0 volt regardless of the switch state (i.e. open or closed).

However if you put a 10k resistor from the CA lead to the V+ of your Arduino you will read 0 when the switch is closed and V+ when the switch is open.

Hope this helps.

As MarkT said the description "pull up" is a usage description. Similar to "rear tire" its still a tire but used in

I LOVE a good analogy!

And, enabling the Arduino's built-in pull-up as Mark suggests should work fine and It's a LOT easier than wiring-up an external one. I've never even considered using an external pull-up on an Arduino input.

@DVDdoug,

I agree, functionally the internal pull up will work. However, in my opinion (and especially for someone still learning electronics) I recommend:

  1. A pullup resistor (10K is OK)
  2. An additional resistor say 5K directly in series with the input pin on the arduino.

My reasoning is:

A) The CA lead can be read with a meter regardless of the state of the arduino.
B) For someone learning, an accidental application of 12V won't fry the arduino. (Assuming the 5k is in series with the input pin.)

However these are all personal design trade off choices.

I've got some 10k pull-ups right here! Step right up! Only $10 each for 1/4 watt versions with super cool racing stripes thrown in for free!

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mixographer:
I've got some 10k pull-ups right here! Step right up! Only $10 each for 1/4 watt versions with super cool racing stripes thrown in for free!

Are these racing stripes brown, black and orange by any chance?

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Nailed it! Those also happen to be the fastest AND best looking-est stripes anywhere!

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