User manual

056 Hour++;

057 if(Hour == 24)

058 {

059 Hour = 0;

060 }

061 }

062 }

063 cnt = 0;

064 }

065

066 delay(10);

067 }

If we were to output the counter readings one to one on the

display, the counter readings below 10 would look strange because

the leading zero would not be displayed. For the clock to have

the familiar »00:00:00«- format, we need to check if the value

is less than 10 before the output.

001 if(Second < 10) lcd.print("0")

If the value is less than 10, a simple output would only display,

e.g. »12:1:8«. However, we check if the value is less and add

a »0« manually if necessary to fill the tens.

CAPACITY METER

Building your own meters with the simplest of media is always

interesting and exciting. Arduino™ permits programming a ca-

pacity meter for small capacitors in the range of 1 nF to approx.

100 µF for our hobby lab at very low costs and effort. This is

how our capacity meter with auto range function works:

At commencement of the measurement, the variable

C_time

initialised with zero. Port D12 is configured as an output and

then immediately switched to LOW (GND), to discharge the

connected capacitor (test piece) before the actual measurement.

After a brief end charging pause of 1 second, port D12 will be

configured as input and the internal pull-up-resistance will be

activated. The pull-up-resistance will now charge the capacitor

to be tested until the port D12 recognises HIGH. The threshold

from when onwards the digital port recognises HIGH is at approx.

3.5 V at an operating voltage of 5 V. This level therefore