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I am making a device that has two external interactions i.e. a button and a infrared sensor. My only problem is that I am using a logic chip for this because it would save me time coding on the Arduino, but now I don't know if the Arduino can cooperate or power the OR CMOS. I am a beginner in the logic and 555 timers field so every time I see them I try to ignore it. I have it now. Tried to draw a schematic and it just clicked. Thank you for trying to help.

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  • \$\begingroup\$ I can't draw a schematic so no luck there. I will keep trying to figure the schematic out but that is hard to do when you don't know if the parts you are using are compatible. \$\endgroup\$ – Jdude2345 Mar 5 '14 at 4:41
  • \$\begingroup\$ Why don't you try to create a schematic showing how you think they should be wired, then we comment on it? \$\endgroup\$ – Ricardo Mar 5 '14 at 5:16
  • \$\begingroup\$ Check the datasheet on both the Arduino (i dont know off hand) for the maximum current draw on each pin. Also check your datasheets and calculate the amount of power you will be drawing. The arduino should be more then enough to power your external circuit. \$\endgroup\$ – Matt Clark Mar 5 '14 at 6:14
  • \$\begingroup\$ What logic chip are you trying to use? \$\endgroup\$ – JimmyB Mar 5 '14 at 16:06
  • \$\begingroup\$ I am using a 74HC32 and I understand it now. Took me a while but I answered my question \$\endgroup\$ – Jdude2345 Apr 4 '14 at 0:50
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I don't know if the arduino can cooperate or power the OR CMOS.

There are many models of Arduino and many clone or compatible Arduino-like devices. An exact answer depends on exactly which you have.

An Arduino typically has a 5V regulator and a 3.3V regulator and can be USB-powered (which may make a difference to the current it can supply). You can check the data sheets for the regulator used on your particular Arduino and make an allowance for the current used by the AVR microcontroller on the PCB. That gives you an idea how much remaining power can safely be drawn from the board for other devices.

In general, yes, you can power a small number of CMOS logic ICs from the power pins on an Arduino. I'd keep an eye on the actual voltage and on regulator temperature.

As Ignacio points out, you need to be aware of the difference betwen 3.3V and 5V signal levels and, if necessary provide for level conversion.

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The "5V" pin provides 5V from the board. The "3.3V" pin provides 3.3V from the board. See the datasheet(s) as to which you can/should connect to Vdd. One of the "GND" pins (doesn't matter which) connects to Vss. Don't forget to tie unused inputs on the logic chip either high or low.

And don't connect a 5V output to a 3.3V input.

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