User manual

any desired colour mix can be set.
Info: the basic circuit is an integrator again so this time the input current depending
on the switch setting can be positive, zero or negative. In the neutral middle position
of the switch, the output voltage should not change. As a matter of fact, the una-
voidable insulation error of the electrolytic capacitor and the output current of the
op-amp leads to slow change.
Mission: modify the switch into a double motion detector using four bare wires. The
share of the two colours is changing depending on which contact you touch with
your finger: 5 points.
12 Earthquake sensor
You will find a 330 k

resistor (orange, orange, yellow) behind the door number 12. It will be used to convert the piezo sound converter into a vibration sensor.
Loud noises and strong vibrations make both LEDs flicker. Raise and lower the entire structure. It will make red and green LEDs flicker alternately. The piezo panel
behaves as an acceleration sensor. When you carry it through the room, your every step is clearly indicated.
Info: the operational amplifier is operated here without negative feedback as a
comparator. Both input voltages are equal in the idle state, so the behaviour at
the output cannot be predicted. The op-amp really has a small offset error, in the
order of 1 mV (millivolt), which is a decisive factor in the idle state. However, as
soon as the signal voltage of the converter markedly exceeds 1 mV, it will define
the output state.
Mission: weigh down the membrane with a small weight of maximum 10g. Thus,
you will improve sensitivity of the sensor to the ground vibrations. Try to place
the sensor in such a way that the steps of a person in the room will be indicated:
5 points.
13 Clap switch
You will find a 100 k

resistor (brown, black, yellow) behind the door number 13. You will use it to make a clap switch toggling the LEDs in response to loud noises
or after tapping the sensor. During installation, observe correct polarity of the electrolytic capacitor, whose minus pole must be connected to the non-inverting
input. In the idle state, the green LED is on. Sensor's adjusting itself to maximum sensitivity takes about half a minute. A noise of a shock causes abrupt toggling
from green to red. Then it will take about half a minute until the circuit switches itself again to the 'green' state. Switching from red to green is a slow crossfade.
After the red LED fully goes out, it takes about ten seconds until the circuit is ready for new noises. However, toggling can occur faster in case of a very strong
signal. In the same way, the 'red' phase can be shortened by a loud noise. If it is continuously very loud, the circuit generates a bit quicker toggling.