NEX ROBOTICS 434 MHz User manual

434 / 315 MHz 8 Channel Secure Remote Control
NEX Robotics Pvt. Ltd. 1
www.nex-robotics.com
434 / 315 MHz 8 Channel Secure
Remote Control
Figure 1: 434 / 315 MHz 8 Channel Secure Remote Control
Introduction
434MHz 8 Channel Secure Remote Control gives out 8 TTL / CMOS level logic outputs.
Four outputs can be used to control direction of the robot and remaining 4 can be used for
other actions, velocity control etc. Switches are arranged in 4 + 4 format for user friendly
control with left and right hand. Remote has range up to 100 feets in outdoor
environment. Each remote control has 10 security bits settings which can be used for
pairing of one transmitter and reciver. Because of the security bit settings command from
one transmitter will not accidentally trigger reciver of the other robot. On the reciver
output is buffered using IC 74HC245 and command output is also displayed on the LEDs.
This remote is based on 434 MHz ASK Transceiver Module and HT640 and HT648
encoder and decoders which can be used for transmitting 8 commands with 10bit security
address setting. You can transmit multiple commands at the same time by simultaneously
pressing multiple keys. Which also means you can use few keys as shift key and probably
control up to 255 devices. Outputs are non latched types. I.E. outputs will remain logic 1
till the remote transmitter’s key is pressed.
Transmitter and reciver both are reverse polarity protected. Both of them have low drop
voltage regulator. Transmitter has power switch. Transmitter and receiver can be powered
by 9V battery or 7 to 12V supply. Remote control has onboard PCB antenna and terminal
for connecting the wire antenna. PCB is made up of high quality glass epoxy material
with the double sided through hole layout for giving additional strength to the switches
and connectors.
Robot can also be controlled by PC by soldering DB25 male printer port connector at the
bottom side of the PC and connecting it with the PC. This feature is not yet tested.

434 / 315 MHz 8 Channel Secure Remote Control
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Note:
•You have to solder pad to select track antenna or a wire antenna before use as
described in the product manual before using remote control.
•For perfect remote control operation make sure that two 0.1uF capacitors are
connected to the motor terminals with respect to motor body and robot chassis and
motor body is grounded.
•Make sure that robot has adequate power available (at least twice of the stall
current of all the motors combined) to avoid interference caused due to power
surges in the supply.
Specifications:
Transmitter and Reciver module: 434 MHz ASK Transceiver Module
Transmitter:
•Frequency: 434 / 315MHz
•Power: 7V to 12V DC, 9V battery can also be used.
•Number of control inputs: 8 (arranged in 4+4 user friendly configuration for left
and right hand)
•Antenna: User selectable PCB track antenna or quarter wavelength wire antenna
•Encoder: HT640 (8 command output and 10 bit security address)
•Reverse polarity protection
•Onboard low drop voltage regulator
•Power switch and Power indicator LED
•Size: 12.5cm x 5cm
Receiver:
•Frequency: 434 / 315MHz
•Power: 7V to 12V DC, 9V battery can also be used.
•Outputs: 8, 5V, TTL / CMOS level, Buffered with IC 74HC245
•8 LEDs displaying status of the commands (can be disabled by removing jumper)
•Antenna: User selectable PCB track antenna or quarter wavelength wire antenna
•Decoder: HT648 (8 command output and 10 bit security address)
•Valid data confirmation output for customization
•Reverse polarity protection
•Onboard low drop voltage regulator
•Power switch and Power indicator LED
•Size: 5.6cm x 4.3cm
Output data type:
•Outputs: 8, 5V, TTL / CMOS level, Buffered with IC 74HC245
•Output gives logic 1 till key of the transmitter is pressed
•You can transmit multiple commands at the same time by simultaneously pressing
multiple keys. Which also means you can use few keys as shift key and probably
control up to 255 devices.
•Outputs are non latched types. I.E. outputs will remain logic 1 till the remote
transmitter’s key is pressed.

434 / 315 MHz 8 Channel Secure Remote Control
NEX Robotics Pvt. Ltd. 3
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•Valid data confirmation output for customization
Kit Contains:
Remote Control Transmitter
Remote Control Receiver
434 MHz ASK Transceiver Module (soldered on the transmitter and reciver)
Transmitter
Figure 2: 434 / 315 MHz 8 Channel Secure Remote Control Transmitter
Remote control transmitter has 8 switches arranged in 4 + 4 configuration. Each key has
number from 0 to 7 corresponding to its bit number. When a particular key is pressed, bit
corresponding to that number on the reciver will become logic 1. To power up the remote,
give 7 to 12V to the power connector and turn on the power switch. You can also power
remote transmitter using 9V battery. Make sure that security bit settings on transmitter
and reciver are identical. All the security bits of the remote control transmitter and reciver
are factory set at logic 0 or 1.
Low drop voltage regulator is used to down convert supply to 5V from 7to 12V input
supply. Remote is reverse polarity protected. Make sure that transmitter module is
inserted in its socket such that non component side of the transmitter is facing upwards as
shown in the figure.
HT640 encoder chip converts the logic inputs from the switches and the security bit
settings from parallel to serial and transmits it via 434 / 315 MHz transmitter module.

434 / 315 MHz 8 Channel Secure Remote Control
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Transmitter has on onboard track antenna. To enable it you have to short pad as shown in
figure 3. For longer range you can solder wire on the pad marked as “ANT”.
Robot can also be controlled by PC by soldering DB25 male printer port connector at the
bottom side of the PC and connecting it with the PC. This feature is not yet tested.
Figure 3: Selecting track antenna / wire antenna on the remote transmitter

434 / 315 MHz 8 Channel Secure Remote Control
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Reciver
Figure 4: 434 / 315 MHz 8 Channel Secure Remote Control Receiver
Remote control receiver has 8 logic output corresponding to 8 switches on the remote
control transmitter. When a particular key is pressed, bit corresponding to that number on
the reciver will become logic 1. Output of the HT648 decoder is buffered using IC
74HC245. Channel output status is also displayed on the LEDs. Output can drive any 5V
TTL / COMS compatible output. Reciver can be powered by 7 to 12V or by 9V battery.
Make sure that security bit settings on transmitter and reciver are identical. All the
security bits of the remote control transmitter and reciver are factory set at logic 0 or 1.
Low drop voltage regulator is used to down convert supply to 5V from 7to 12V input
supply. Remote is reverse polarity protected.
HT648 decoder chip receives the serial data from the wireless reciver and decodes it in to
parallel. If security bits are matched it makes pin VT as logic 1 and outputs the bits
corresponding to the switches on the remote transmitter.
Receiver has on onboard track antenna. To enable it you have to short pad as shown in
figure 5. For longer range you can solder wire on the pad marked as “ANT”.
Remove Jumper for LEDs (J1) to turn off the LEDs used for channel status indication.

434 / 315 MHz 8 Channel Secure Remote Control
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Figure 5: Selecting track antenna / wire antenna on the remote receiver
Note: For more information on the remote control operation, refer to the HT640 and
HT648 datasheets on the product page.
Schematic:
Figure 6: Representative schematics (Courtesy HT640 ad HT648 datasheet)

434 / 315 MHz 8 Channel Secure Remote Control
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Product’s electronics is static sensitive. Use the product in static free
environment.
Read the user manuals completely before start using this product
Recycling:
Almost all the part of this product are recyclable. Please send this product to the
recycling plant after its operational life. By recycling we can contribute to cleaner
and healthier environment for the future generations.