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HITCHIKER Add-on Channels
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  • 75MHz SURFACE VEHICLE or 72MHz AIRCRAFT FREQUENCIES

  • KH832 COMPLETE SYSTEM : 39CH   with FP-8UAPS for BOATS & ROBOTS

  • KH816 COMPLETE SYSTEM : 23 CH  with FP-8UAPS for BOATS & ROBOTS

  • KH812 COMPLETE SYSTEM : 19 CH   with FP-8UAPS for AIRPLANES

  • ADD 12,16 or 32 INDEPENDENT & SIMULTANEOUS CHANNELS TO FUTABA PCM1024

  • KH16T or KH32T TRANSMITTER KEYPAD

  • KH32R, KH16R or KH12R RECEPTORS with SERVO COMMAND OUTPUTS & 5A 30VDC ELECTRONIC SWITCHES

 
The HITCHIKER series provides the extra R/C channels to totally control your hobby robot, special EFX project, or detail your 1/4 scale R/C plane. It is perfect for controlling submarines and their complex plumbing. Making your dream scale R/C boat fully operational is now easier than ever. Eliminate fussy servo-cammed microswitch kluges forever.

All HITCHIKER products are compatible with Futaba's excellent Pulse Code Modulation method trademarked as PCM1024, only.  Futaba offers a number of radio systems, both wheel and stick types using PCM1024.  For our KH832, KH816 & KH812 complete KeyKoder systems we chose the Futaba FP-8UAPS R/C set. We call it the HITCHIKER because the add-on transmitter KeyPad hitches onto the base of a Futaba FP-8UAP transmitter with your thumb to create 12, 16, or 32 new on-off channels.  It plugs into the trainer connector!  PCM1024 is a significant improvement over FM because it transmits the servo commands as digital words with special mathematical properties that facilitate accurate reception. Servo jitters are a thing of the past. For a detailed understanding of The PCM Advantage see pcmadv.htm .

VANTEC fully harnesses Futaba's PCM coding to reliably pack the additional controls onto one of the Futaba R/C servo channels. The new controls are independent and operate simultaneously. The remaining conventional channels are not affected.  By far the most popular devices are the 12, 16 and 32 "on-off" channel KeyPad additions that this page describes but the variety of KeyKoder functions is described on #KeyKoder Technology .

VANTEC recommends our complete systems that include the entire Futaba FP-8UAP R/C set with 8 conventional servo channels, servos and all, plus the HITCHIKER KeyPad and Receptor; and we warranty the entire system.

The KH816 complete system has 7 conventional servo channels and 16 KeyKoder on-off electronic switch channels for 23 channels total.  Note it simultanuously includes the 8 new servo outputs described in the KH812 paragraph below.

The KH832 complete system has 7 conventional servo channels and 32 KeyKoder on-off switch channels to yield 39 channels total. Note it simultanuously includes the 8 new servo outputs described in the KH812 paragraph below. Generally these versions are employed in boats and robots.

The KH812 complete system has 7 conventional servo channels and 12 added KeyKoder channels. It's KeyKoder Receptor features 2 three-position regular servo command ouputs, 6 two-position regular servo command outputs, and only 4 electronic switches and finds use primarly in model aircraft. It has 19 channels total.  Since the servo command outputs are just like the signals coming from a Futaba receiver you can plug-in up to 8 new conventional servos for auxilliary functions like bomb bay doors, bomb release, or parachutists.  The electronic switches can be used to control engine ignition, starting, lights and camera.

Each new KeyPad channel is actuated by a special toggle switch that can operate momentarily like a push button by pressing down; it will spring back to center off. Or switch it "On" continuously like a normal toggle switch by flipping it up. Any number of switches may be activated at once. Each switch is labeled 1-16 or 1-32. These new on-off channel numbers correspond to the outputs on the Receptor at the receiver end of things.  The KeyPad understands and "speaks" PCM1024; it interjects its new data onto one of the regular servo channels. This means you lose the normal operation of the selected channel; normally the retract switch channel 5 is sacrificed.

A Receptor add-on box plugs into the Futaba R/C receiver like a servo and separates the KeyPad commands back into 12, 16 or 32 individual outputs. These on-off or two-state outputs manifest themselves several ways depending upon the Receptor model.
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SWITCH OUTPUTS: The KH16R and KH32R Receptors have a corresponding number of 5 Ampere on-off electronic switch outputs that operate as current sinks. This means they switch to ground to complete the circuit to operate your device. Because they switch to ground they easily accomodate a variety of lights, horns, motors and other loads operating on a variety of voltages up to 30VDC by simply using different batteries or taps on a series connected set of batteries. See Figure 1 above for examples. Total current controlled at one time should be limited to 25 Amps.
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Figure 2 shows a simple "lossy" bridge circuit for forward and reverse momentary operation of a small motor such as the zoom and focus motors found in some video cameras. The resistors provide automatic current limiting and un-equal resistor values can be used for different forward and reverse speeds. Experimentation is required but for a 12V battery the bridge resistors should be greater than 15 ohms;  for 24V battery - 30 ohms.

Relays may be used to amplify the current capacity or provide handy operating logic such as reversing high current motors.

Figure 3 shows efficient operation of reversing motors up to 5 amps using a single 5 amp relay and 5 amp diode from Radio Shack. If your application runs into a physical stop use the limit switches shown to prevent dangerous stalled motor operation. Variation: automatic reverse/return by connecting wire "REV" to ground instead of a Receptor output (saves a KeyKoder channel too).

Figure 4 shows the use of relays to operate much larger motors, over 4 amps. In this circuit the limit switches need only be capable of handling the relay coil current. The automatic reverse/return idea above may be applied here also.

The KH12R Receptor for airplane applications has only 4 on-off electronic switch outputs but the same principles apply.

If the Receptor fails to receive KeyPad signals it uses the old information for a brief time and then enters a fail safe mode. In the fail safe mode all electronic switches are turned off except KCh14 & 15 which maintain their last state. You could use KCh14 to command lighting since your vehicle could be at rest but illuminated with the transmitter turned off; great for dinner flotillas!

SERVO COMMAND PULSE OUTPUTS: In addition to the electronic switches the first 8 of the Hitchiker Receptor channels simultaneously have conventional Servo Command Pulse outputs that drive regular R/C servos or speed controls to two or three pre-determined positions. Regular plug-in servo connections are provided on the VANTEC Receptor.  A separate 4.8V battery pack or 12V-to-5V power supply may be used to power these servos. 

Servo Command Pulse outputs 1-2 and 3-4 are the three position servo outputs. The two and three positions are designed so that a three position servo output shares a transmitter KeyPad switch with a two position servo output. For example: KSw1 controls SCP1 which operates as as two position actuator. But KSw1 also commands the second SCP2 servo, along with KSw2, for one of three positions. The actual servo positions are adjustable by three pots on the Receptor. They are grouped to provide a variety of combinations but the most useful are factory set and delineated in Fig 5.
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SURFACE FREQUENCIES: 75 MHz transmit modules and re-tuned FP-R148 or FP-R129P receivers are available when ordered as a complete system; there is no additional charge to have your transmitter legal.

The HITCHIKER series has a limited one-year warranty based upon a nominal repair charge for units not tampered with or abused. Details available in Ordering.  Interference from regular servo data sent by other PCM1024, AM or FM transmitters on your frequency, although guarded against, can occur to the HITCHIKER channels or regular servo channels. This can be avoided by proper frequency control protocol and other procedures. For secure channels and a truly unique transmitter identication code purchase the industrial strength KIK29 or KIK44 systems. There are some plausible mix 'n match possiblities between the Hitchiker series and other KeyKoder products like the more expensive KIK Kommander industrial KeyKoders, for example: to realize sink or source MOSFET switch outputs.  See the KeyKoder Products Overview keyov.htm.
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Note: Our products are not safety devices nor for use in life-critical or life support systems. Specifications and price subject to change without notice. Patented. Some trade names, trademarks & content owned by others.
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