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11 years, 2 months ago.
How much current one pin can take?
i want to connect this sensor , http://www.ia.omron.com/product/item/e3z_7013d/ and the output is 0 to 100ma.
2 Answers
11 years, 2 months ago.
The sensor has an open collector NPN output that can draw a max of 100mA. You should connect a pull-up resistor of maybe 1K or so between the sensor output (black wire) and mbed 3V3. Also connect the sensor output to one of mbed digital inputs. Finally make sure you have mbed ground connected to the sensors GND (blue wire). Obviously, the sensor also needs its own powersupply (brown wire, voltage between +12 and +24V, blue wire for ground).
When the sensor activates the mbed input will switch between 3V3 and about 1V. Note that the 1V minimum maybe slightly critical for reliably detecting a logic 0 on mbed. Some experimentation may be needed.
11 years, 2 months ago.
As a rough guide for the output from an mbed, don't try drawing more than 10mA from a pin, however this would input into the mbed, and since the current is going to be very small, there shouldn't be a problem.