The night lighting for R/C helicopter
HeliStrobe device is installed in R/C model of helicopter and controls operation of lighting elements on the sides of the model. Lighting elements are bright LEDs directed towards the rotor and the body of the model. The sequence of flashes controlled by the microcontroller provides an image of an immovable figure formed by the rotor. The shape of the figure is chosen from 15 various versions. The image of the model brightly lighted in the both sides in night is the same as in daytime. A change of the colour of lighting causes a change of the colour of the model.
Description of the device
The device is installed in the same body with a rotation sensor for the rotor. It should be installed under or over the gear fixed on the axle of the main rotor. A magnet is glued into the gear, and the sensor of the device responds to shifts of the magnet. The location of the sensor on the device is marked with the red sign. This plane of the device should be faced towards the magnet. The gap between the magnet and the sensor should be 2...4 mm. For fixing the magnet, a hole of 4 mm diameter is drilled in the gear. Before fixing the magnet with adhesive, a response of the sensor to it should be checked up; if it is absent, the magnet should be turned and its opposite end should be inserted. A metal cylinder is glued from the opposite side of the gear, seeking for the balance preservation; its diameter is identical with the magnet. The sensor and the magnet should coincide when the main rotor's blades are oriented along the body of the helicopter. After having selected the precise position, the sensor is fixed on the frame of the helicopter with the help of the double-sided sticky tape and the ties. Two feeding wires of the red (+) and black (-) color, outstretching from the device, are to be connected to the feeding connectors or to the switch. The range of the feeding voltage can vary between 7 and 25 V (two to six sections of lithium accumulators). Please, observe the polarity while connecting power supply. The lighting elements are connected to the wires, marked as “LEFT” and “RIGHT”. The white wires - the plus of feeding; the black wires - the minus of feeding. After switching-on, light appears for a short time; then it will appear after five seconds. After the second switching-on, the device can operate. Lighting will appear on rotation of the rotor only. For choosing another shape of lighting the rotor, disconnect and reconnect power supply of the device. After the first switching-on the light, turn the rotor manually for three times during five seconds. Then, after three short flashes, you can choose a shape of lighting. You'll choose a desirable shape on rotating the rotor; each revolution is accompanied by a short appearance of light. The number of revolutions varies between zero and fourteen. If you stop rotation, three short appearances of light will follow after five seconds and the chosen shape of figure will be set. All shapes selectable are provided below. If You wish to turn the figure at 180º, then exchange positioning of the left and right light elements. The duration of operation with a battery depends on the capacity of the battery and the power of the lighting elements. The maximum load current is 5A and if the feeding voltage is 20V; they ensure power of 100W for each of two lighting channels. Such power is sufficient for 2000 ordinary LEDs on each side! We recommend using superbright LEDs of maximum power to ensure the summarized power of 10-20W.
The device HeliStrobe, the view from the side of the sensor (the label is on the opposite side).
The scheme of installation of the device.
The images of figures formed by the lighted rotor. The numbering of the figures starts from 0, not from 1, that corresponds to the number of revolutions of the rotor required for choosing a shape of the figure.
Technical data
Supply voltage - 7...20V
Load current - <5A
Consumption current - 15mA
Sizes - 34*12*4mm
Length of conductors - 30cm
Weight - 15g
The set:
Device HeliStrobe
Magnet
Counterbalance
Set of resistors (1; 2.2; 4.7 Ohm, 3x2 pcs)
(1 Ohm resistor begins with brown line; 2.2 - red line; 4.7 - yellow line is first)
Choosing and installing the lighting elements
Superbright LEDs, such as LuxeonTM or Z-Power, are usable. Elements of any colours can be used. The recommended summarized power - no less than 10W. Use elements, designed for fixed voltage, for example -12 V (three-section Li-po battery can be used). Else, LEDs should be connected via a resistor. For determining the required rated value of the resistor, the maximum values of the voltage and current for the chosen lighting elements should be got to know. If several elements of the same type are connected in series, their voltages are summarized; if they are connected in parallel, their currents are summarized. Then, the voltage difference between the battery and the lighting element is found:
Vr=Vbat-Vled
Now the minimum value of the resistance is found
R=Vr/I
Now the minimum power of the resistor is found:
P=Vr*I
Do not forget that the maximum voltage of the battery exceeds its rated voltage. So, the voltage of fully charged two-section lithium battery is 8.4V, not 7.4V.
The example of calculation of a lighting element:
8.4V lithium battery
LED Luxeon Sar , 3.42V, 0.7A
Series connection of two elements, V=3.42+3.42=6.84
Vr=8.4-6.84=1.56
R=1.56/0.7=2.2
P=1.1
Because LEDs operate in pulsed mode, the found values can be rounded down: 2 Ohm resistor with power of 1W will be required. The scheme consumes current of 0.7A; this means that seven such schemes can be connected in parallel on each side and the summarized power will be 70W. The light provided by such elements will be stronger than the light of a vehicle's light.
Examples of the connection schemes:
The lighting elements can be fixed to the landing skids - in such a case, the plane of the rotor is lighted very well and the body is lighted partially. To ensure a better lighting of the body, elements can be fixed to a skid fixed aside the body. The skid is made of a carbon tube 1 m long and with the external diameter of 10 mm; the thickness of its walls should be 0.5-1 mm. A tube of a less diameter can vibrate considerably. The center of the tube should be fixed to the frame of the helicopter, and the lighting elements oriented towards the main rotor and the body of the model should be fixed to its ends.
The limited warranty and responsibility
A replacement of a defected device is possible during six months. If a device is damaged because of incorrect connection or includes signs of mechanical damage, it shall not be replaced. Please, observe the polarity of connection. The manufacturer assumes no liability for any damage resulted by using the device. The copyright of the manufacturer is protected by a patent.
