Wiring up the Circuit

Referencing the pinout of the Arduino nano in {numref}`

` below, the programmer must first identify where each of the three hardware elements will be connected, ensuring that the pins/ports meet the requirements.

• For the push button switch, this will be a digital signal (on/off) so can be connected to any GPIO pin.

  • Looking at the other hardware requirements, this should avoid the pins connected to the ADC and leave a full port of input pins for the LEDs. For this example, connection D8 of the nano board is a convenient pin to use, this is connected to PB0, i.e. Port B bit 0[^note].

• For the analogue input, this can be connected to any of the GPIO pins which is also connected to the ADC.

  • Looking at Fig. 113, these connections are labelled A0 – A7 on the nano board. Connection A0 is connected to PC0, i.e. Port C bit 0 which is also connected to ADC[0] – ADC channel 0.

• The LEDs can be connected to any digital GPIO pin, but ideally will be 8 pins on the same port.

  • Looking at Fig. 113 and the two pins we have used above, connections D0 – D7 can be used which corresponds to Port D bits 0-7[1].

A possible assembly is illustrated in Fig. 114[2]

Fig. 113 Arduino Nano Pinout - Arduino Nano links.

Fig. 114 The circuit assembled on breadboard

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[1]

pins across multiple ports can be used but this will make the programming more complicated.

[2]

When building this circuit, it is advised that the red wire from the 5V output of the Arduino nano board to the bottom rail of the breadboard is replaced with a 220 Ohm resistor, this will protect the USB circuitry within the PC in the event of any wiring faults/short circuits between the rails.