This is very common problem to Arduino users. As the new versions of IDE has been released, many libraries has been updated. All of these previous Wprogram.h, Wiring.h, String.h has been included under single header file named Arduino.h
I came across this error/warning several times. Just needed to rename the header file to <Arduino.h> and problem get solved.
My brother’s Offset printing machine was giving him trouble counting pages. There is voltage stabilizer connected to protect the machine from voltage beyond 110V. Whenever printer shut-off due to voltage fluctuation the counter of machine goes to zero again. This situation irritates him, as remembering pages is not easy while printing 1000-2000 pages at a time.
This picture shows four 7-segment displays connected that can show maximum number of 99999 pages. Continue reading