The basis of this design is a solar battery used in mobile electric shepherds.
To orient it relative to the sun in a horizontal plane, a movable base from the children's game “Behind the wheel” was used with the replacement of the too fast electric motor with a reversible drive with a gearbox.
Rotation transmission produced with a rubber roller.
In the vertical plane, the SB is induced by the download drive from the video recorder.
It was necessary to remove the mechanical travel stops.
Two dial gauges are used to control the voltage and current output from the SB. Because the setting is made according to the maximum deviation of the arrow, and not according to the absolute value of the parameter, calibration was not carried out, the devices operate in indicator mode.
Light sensors along both coordinates – horizontal and vertical – there are 4 identical photoresistors, fixed on the upper part of the structure.
The signal from them is processed by two identical automation units, which convert the analog signal from the sensors into a PWM signal for controlling the electric motor. Automation works in such a way that the signal from oppositely located sensors is the same.
This is followed by a comparator – the basis of the circuit. Zener diode VD1 is required for guaranteed closing of the transistor.
The dual comparator provides reversal and the necessary hysteresis, “dead zone”, otherwise the position correction will be continuous.
Diagram of one of the two automation units, on the next. scheme, its designation is BA. The motor is controlled by a bridge circuit.
Full layout scheme. Here S3 and S4 are limit switches that prevent the extreme slope of the SB.
When setting up the SB manually, with the help of switches, it aims at the sun according to the maximum reading of the devices, after which it is necessary to turn on the automation, which will monitor the brightest light source in its field of view. As a rule, this is the sun, but with a bright flashlight, the automation can be deceived and taken aside. True, then she finds the star without any problems. It is better to turn off at night, so as not to plant the battery in vain.
The electricity obtained during the tests was enough to charge a battery of AA size finger batteries, although in the standard description of the electric shepherd mentions a car battery.