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Archive for April, 2011
Posted by Zaitsevsky | Apr 18, 2011 @ 04:17 AM | 7,641 Views
Open Source project DirectionFinder
schematic and firmware :

Automated pointing of the video-camera to the object, selected for shooting (1 min 41 sec)

Experimental device DirectionFinder can be applied for following purposes: automatic pointing of a camera towards the object of shooting; automatic persecution of the specified target; automatic prevention of a collision with the specified target. A special infrared radiator is mounted on the object to be watched by the device. Alternatively, the object can be marked by reflected radiation, for example, laser's ray. Infrared radiation is invisible for human eyes. Infrared radiation is modulated, so the device will not react to any extraneous infrared sources. The device is connected between the receiver and the servomechanism. The device can operate in the autonomous mode, without a control signal from the receiver. One device controls a single plane of rotation; so for control in the horizontal and the vertical directions, two control channels and two DirectionFinder devices are required.

The examples of application of the device:
1. The device is mounted on a radio-controlled vehicle and enables it to pass automatically through the specified gate; to persecute automatically the specified vehicle; to avoid automatically a collision with the specified obstacle.
2. The device is mounted on the active suspension of a video camera and enables the camera to keep automatically the specified object in the center of the shot.
3. The device is mounted on a radio-controlled model of an airplane and enables it automatically to fly above the specified areas or to get into recovery net.
Posted by Zaitsevsky | Apr 11, 2011 @ 05:01 AM | 9,084 Views
Servomechanism with a simple magnetic position sensor
(MI Servo with $0.5 magnetic induction sensor)

Servomechanism with a magnetic position sensor (0 min 29 sec)

Such a servomechanism is usable for controlling various mechanizations, such as gear extension or rotation of any element via a supplemental reducer. I used such sensors for leveling-off the video camera in respect of the position of the mechanical gyroscope. A Hall sensor ensures a proportional response to a change of the magnetic field, taking into account the polarity. An absence of magnetic field or the neutral magnetic field (in case of equal distances from the opposite poles) in the transformed servomechanism conforms to the neutral position of the potentiometer in an ordinary servomechanism. The sensor responds to a shift or rotation of the magnet; it is also possible to use two magnets in two extreme positions. The scheme of connection:

The mechanical gyroscope used as a virtual horizon:

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Posted by Zaitsevsky | Apr 04, 2011 @ 12:57 AM | 11,815 Views
A servomechanism with a horizon sensor. Can be used on a camera gimbal or an aircraft.

A servomechanism with a horizon sensor (0 min 12 sec)

Such a servomechanism is usable for controlling the bank of the aircraft or the inclination of the camera. You'll be able to control the inclination of the camera; the neutral position will conform to the horizon line. In addition, it is possible to control the ailerons of the aircraft and to incline the aircraft to the desired angle in respect of the horizon. If the horizon line is not symmetric, a bank of the aircraft appears. The scheme of the sensor:


IR photocells are fixed on the movable part of the controlled gimbal of the camera or on the opposite ends of the controlled model. A signal of the sensor is applied to an ordinary servomechanism instead of the internal potentiometer. The potentiometer of the servomechanism is connected to the negative terminal, to the reference voltage and has one output (3 conductors); the infrared sensor is connected in the same way.

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