The SYMA 608 Mosquito helicopter is one of the copies of the original Micro-mosqito helicopter. The box contains the following
1. Mosquito helicopter
2. Transmitter
3. 9V PP3 Battery for transmitter
4. Spare tail rotter blades
5. Antenna for transmitter
The SYMA 608 I purchased was a 40 MHz model. The exact frequency is 40.680 MHz. This is a three channel helicopter. It is a coaxial helicopter, what that means is that it has two main rotor blades using a single axle. The two blades spin in opposite direction, creating stability. A tail roter is present in unconvential horizontal direct to tilt the helicopter backward to move backwards and forward to move forwards. The turning left and right is achieved by the difference in the speeds of the two blades.
Two tactile buttons on the transmitter are used for the trim. Basically, when the helicopter is first air borne it will rotate in either left or right direction. The trim buttons help bring the speed of the two motors together so that the heli can be stable.
The SYMA helicopter is an RTF (ready to fly helicopter). it has four LEDS, two green LEDs are used as mosquito EYEs like the original Micro Mosquito helicopter. Two additional dual Color (RED and BLUE) LEDs are used to create lighting effect around the heli. This is first time I have seen these in a mosquito helicopter. The helicopter is very light, and used a 180mAh Lithium Polymer battery (although the box says 210mAh).
The transmitter
The transmitter is based on a three main segments
1. PCM generator
2. 40.680 MHz third overtone oscillator
3. Simple one stage amplifier transmitter
1. PCM Generator
The PCM generator is an unmarked 18 Pin PDIP IC with a 4 MHz Crystal. This also suggests that it might be a microcontroller. The input to the microcontroller is the two trim tactile switches (buttons). Also three code generating pads are used as inputs. When the user moves the control sticks, a metal brush connects some pads to 5V supply. So as the brush moves over these pads, it creates a number of codes to the microcontroller. There seem to be about 14 codes (4 bit wide) for the throttle stick, 5 codes for Left and right rudder where the rudder is on normally in the center and three for forward /backward movement where the stick is normally in the centre.
2. The Oscillator
The PCM generator creates a code that is then sent to the 40.680MHz transmitter. the transmitter works in OOK (on off keying). So the oscillator is always on at 40.680mhz. This is third over tone helicopter, so first tone is around 14mhz. The 2SC1815 transister keep the oscillator is a stable oscillation when the transmitter is on.
3. The Amplifier
When a zero comes in from he PCM generator the amplifier stays off. When a one comes in the amplifier is switched ON. the Amplifier is a 2SC8050 transistor. and its collecoer input is from the PCM generator. The antenna is a simple telescopic monopole antenna as used in most RC transmitters.
1. Mosquito helicopter
2. Transmitter
3. 9V PP3 Battery for transmitter
4. Spare tail rotter blades
5. Antenna for transmitter
The SYMA 608 I purchased was a 40 MHz model. The exact frequency is 40.680 MHz. This is a three channel helicopter. It is a coaxial helicopter, what that means is that it has two main rotor blades using a single axle. The two blades spin in opposite direction, creating stability. A tail roter is present in unconvential horizontal direct to tilt the helicopter backward to move backwards and forward to move forwards. The turning left and right is achieved by the difference in the speeds of the two blades.
Two tactile buttons on the transmitter are used for the trim. Basically, when the helicopter is first air borne it will rotate in either left or right direction. The trim buttons help bring the speed of the two motors together so that the heli can be stable.
The SYMA helicopter is an RTF (ready to fly helicopter). it has four LEDS, two green LEDs are used as mosquito EYEs like the original Micro Mosquito helicopter. Two additional dual Color (RED and BLUE) LEDs are used to create lighting effect around the heli. This is first time I have seen these in a mosquito helicopter. The helicopter is very light, and used a 180mAh Lithium Polymer battery (although the box says 210mAh).
The transmitter
The transmitter is based on a three main segments
1. PCM generator
2. 40.680 MHz third overtone oscillator
3. Simple one stage amplifier transmitter
1. PCM Generator
The PCM generator is an unmarked 18 Pin PDIP IC with a 4 MHz Crystal. This also suggests that it might be a microcontroller. The input to the microcontroller is the two trim tactile switches (buttons). Also three code generating pads are used as inputs. When the user moves the control sticks, a metal brush connects some pads to 5V supply. So as the brush moves over these pads, it creates a number of codes to the microcontroller. There seem to be about 14 codes (4 bit wide) for the throttle stick, 5 codes for Left and right rudder where the rudder is on normally in the center and three for forward /backward movement where the stick is normally in the centre.
2. The Oscillator
The PCM generator creates a code that is then sent to the 40.680MHz transmitter. the transmitter works in OOK (on off keying). So the oscillator is always on at 40.680mhz. This is third over tone helicopter, so first tone is around 14mhz. The 2SC1815 transister keep the oscillator is a stable oscillation when the transmitter is on.
3. The Amplifier
When a zero comes in from he PCM generator the amplifier stays off. When a one comes in the amplifier is switched ON. the Amplifier is a 2SC8050 transistor. and its collecoer input is from the PCM generator. The antenna is a simple telescopic monopole antenna as used in most RC transmitters.
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