Modern electronics allows products –
consumer, industrial and scientific – to be produced with more
features in smaller packages at less cost than ever before.
Not too long ago, the controller for an appliance such as a
washing machine or microwave oven would have been a mechanical timer, or perhaps
discrete components (switches, transistors and 4000 series logic, etc).
TECHNICAL SPECIFICATIONS - Up/Down Counter
||9-15V DC (<40mA @ 12V)
||Count Up (default), Count Down, Count Disable, Overflow, Reset
||0000 to 9999 or 0000 to 0001 (0000,9999,9998, ... 0001)
||Maximum count rate of 30 to 35 counts per second
||Reset, Count (negative edge triggered), Count down
||NPN Transistor, 100mA @ 30V
||14mm red LED, 7-segment common anode
||51mm x 63mm
||10-pin SIL header pins, 0.1"
However, all these things take precious space and are costly to
produce. Often they're difficult to update or reuse for different product models
Today, these problems are neatly and cheaply solved with
microcontrollers – single chip computers complete with IO pins, RAM, Program
storage (ROM) and sometimes other useful features like ADCs, UARTS and PWM
One simply arranges for relevant inputs (switches and sensors)
and outputs (motor and solenoid drivers, LEDs and displays) to be connected to
the microcontroller and then write some software to manage the lot.
The space saving and cost effectiveness of these small wonders
are reason enough to use them. But when you consider the flexibility they
provide to adapt the control system to changes in the device or consumer
demanded functionality they are indispensable.