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JR Technique

06/28/2002 by

Copyright:© 2002 Horizon Hobby, Inc.

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Page 1: How To Get More 'Channels' From Your 10x

Scale, jet and sailplane guys-rejoice! Thanks to some creative thinking by our R&D manager John Adams, you can split one channel into 2, 3, 4 or even 5 on-off functions using retract servos and the new JR MatchBox™ system. The only catch: you'll have to operate these functions sequentially.

Because of the sequential limitation, this system is best used for two-position, on-off functions like retractable gear, tank drops, bomb drops, lights, canopies, smoke, etc. Our suggestion would be to always keep essential flight controls like ailerons, elevator and rudder on normal controls.

Our goal is to show you the basic idea-how to use the MatchBox with one standard and three retract servos to get the five functions to operate from one channel. Obviously, when you consider that any of these servos could trip an air or hydraulic valve, the potential applications become pretty vast. And while this is written for 10X owners, the core idea applies to any radio.

What you'll need to get five functions from one knob:
3 JR retract servos:

1 JR standard proportional servo:
(This may differ, depending on the requirements of your aircraft.)
1 JR MatchBox:

You will also need 2 micro switches (such as TAM75010).

This diagram illustrates a typical "split" channel setup using the MatchBox system.


Basically, we're going to use the MatchBox to skew the kick points of two retract servos off of neutral. The third will kick at neutral, and the proportional servo will travel through its full arc and contact micro switches at the end of its travel.
Initially I had trouble catching on to John's core idea. I took his advice, plugged the MatchBox into the throttle channel and used a regular, proportional servo to literally "see" the neutral shift with a single armed servo horn.

Here's where to begin:

  1. Plug the MatchBox into the receiver's throttle channel.
  2. Plug the proportional servo into port 1 of the MatchBox (if you've been playing with the MatchBox, reset it per the instructions).
  3. Make sure the servo moves with the throttle channel and put a single sided servo arm at a perpendicular position-your "center".
  4. Move the MatchBox dial to 1. Push the "INCR" button, and watch the servo arm skew the neutral clockwise. Keep going until the red light stops blinking (takes about 10 seconds). The neutral should now be off about 10 degrees from center.
  5. Move the servo to the port #2 of the MatchBox. You will see the arm go back to center.
  6. Move the dial to 2. Push the "DEC" button to skew the servo counterclockwise as far as it'll gov (red light out again).
  7. Return the dial to "0" (this is important, as it'll memorize your settings). You have now created three different neutrals (the 3rd and 4th ports are still at the original "middle" position).
  8. Plug the three retract servos into ports 1,2 and 3 of the MatchBox. By moving the throttle stick slowly, you'll see how you can operate the three servos independently.
  9. Transfer the MatchBox "to RX" lead from the throttle channel to the Aux 4 port in the receiver. By moving the Aux 4 dial on your transmitter, you canmove all three retract servos at independent points.
  10. Next, plug the proportional servo into the remaining slot (#4) of the MatchBox. As you'll see, it'll move in the full arc (your endpoints are adjustable through code 12, Travel Adjust).

You've done it - the proportional servo contacts the microswitches at the end of travel, while tripping the retract servos independently throughout the channel's travel.

Don't want to use a dial? You can use switches or snap roll buttons to activate these servos, but the programming is more complex (see sidebar for an example).

Someday we'll have more channels for greater simplicity. In the meantime, we hope this'll help keep you moving forward with your favorite brand.