Instructions

Game and Knowledge in Electronics-Lab

You are now familiar with the function of the connectors MO7 and

MO8, where the LEDs are connected. The abbreviation MO stands

for Micro-controller Output. This is the visible part of electronic

switches inside the micro-controller, which are controlled by a

programme. To be precise, they are selector switches, which connect

the connector to the negative pole or to the positive pole. On - off -

on - off, as the programme commands.

There are also inputs, which are named MI1 to MI6 (MI = Micro-

controller Input). A programme can contain a query: Is there a current

at the input or not? This will tell us whether a connected switch

is pressed or not. The programme could specify: If the switch is

pressed, something will happen.

The input MI5 can do even more. It can’t only determine whether

there is a current or not, it can also measure the voltage. In this case,

the voltage is higher when the potentiometer is turned to the left. The

programme measures a high voltage and then creates a long delay.

When turning the knob all the way to the right, the impedance is

the greatest and the voltage at input MI5 the smallest. That’s why

the ﬂashes and beeps are not very fast. Could they be even faster?

Fast sounds

Think about it. If you pulled a cable from the variable resistor, the

impedance should be even greater, indeﬁnitely great in fact. Could

the ﬂashing then be even faster? Try it!