Immersion RC EzUHF Series Overview & Operating Instructions
ImmersionRC | EzUHF R/C Control System
1
EzUHF R/C Control System
Overview & Operating Instructions
Nov 2010, for Firmware v1.18
ImmersionRC | EzUHF R/C Control System
2
Table of Contents
Overview ....................................................................................................................................................... 3
Features/Specifications ............................................................................................................................. 3
Security ..................................................................................................................................................... 4
Radio Licensing .......................................................................................................................................... 4
EzUHF Transmitter ........................................................................................................................................ 4
Powering the transmitter.......................................................................................................................... 4
Binding ...................................................................................................................................................... 5
Failsafe ...................................................................................................................................................... 6
Power Level control .................................................................................................................................. 6
Range Testing ............................................................................................................................................ 6
Transmitter Compatibility ......................................................................................................................... 7
S-Video pin-out: .................................................................................................................................... 7
PPM Input & Head-Tracker input pin-out: ............................................................................................ 7
Futaba (square) to EzUHF cable: ............................................................................................................... 8
Multiplex (DIN) to EzUHF (Mini-DIN) cable: .............................................................................................. 9
Cabling the TrackR2 to the EzUHF Transmitter: ..................................................................................... 10
EzUHF Receivers .......................................................................................................................................... 11
EzUHF Receiver, 8 channel version, Connections ................................................................................... 12
Powering the Rx when using high-powered servos ............................................................................ 12
Receiver antenna configuration .............................................................................................................. 13
Driver/Software Installation on a PC .......................................................................................................... 13
EzUHF -> EzOSD link ................................................................................................................................ 13
Antenna Selection ....................................................................................................................................... 15
Diamond SRH771 .................................................................................................................................... 15
Active Robots 433MHz Straight .............................................................................................................. 16
Active Robots 433MHz R/A ..................................................................................................................... 16
Antenna extension cables ....................................................................................................................... 16
IMPORTANT: Known Sources of Interference ........................................................................................ 18
Appendix A: Binding multiple transmitters to a single receiver ................................................................. 19
Appendix B: Diagnostics .............................................................................................................................. 20
ImmersionRC | EzUHF R/C Control System
3
Overview
The EzUHF R/C control system is a reliable R/C control uplink for FPV and UAV pilots who desire a robust
control system for safe control at longer distances.
It was designed with the FPV/UAV pilot in mind, the only such system with a dedicated head-tracker
port, ensuring compatibility with a wide range of radios.
An ‘Aux Ctrl’ port is available to connect to a ‘control board’, for in-flight UAV configuration without
sacrificing valuable control channels.
Features/Specifications
Reliable FHSS Link (Frequency Hopping, Spread Spectrum)
433MHz/70cm Ham band operation
Options for 431-433MHz, 433-435MHz, 435-437MHz.
Spectrally clean GFSK modulation
600mW (~28dBm) output power, with 200mW low-power mode
Direct head-tracker input, adding head-tracker compatibility to most radios
Power switch, boost power when at long range (optionally drive from unused control on the R/C Tx)
Standard SMA antenna connector, compatibility with 433MHz/70cm Ham-band antennas
Flexible buffered, AC-coupled, PPM input, ensures compatibility with 3.3v thru 9.6v PPM levels
Standard USB port (Mini-A) for firmware upgrades, and system configuration
Single pushbutton learning of failsafe positions
Binding function, which allows binding Single Tx->Rx, Multi Tx->Rx, and Single Tx->Multi Rx
Mates with 8 channel, and 4 channel EzUHF receivers
Spectrum analyzer built into EzUHF receivers, to aid in debugging RF interference
Power sourced directly from the R/C Tx (Futaba), or optional DC power jack
Built in receiver, for future expansion
Custom extruded brushed aluminum enclosure
Dimensions 85 x 74 x 23mm 118g
Power Requirements: 9-12v DC 250 mA @ 12v, in 600mW mode, 85mA @ 12v, in 200mW mode
ImmersionRC | EzUHF R/C Control System
4
Security
The ImmersionRC team does not promote reckless long-range flight, where property and/or lives are put
at risk.
This R/C control system was brought to the market for use by responsible end-users, who are aware of,
and comply with, local legislation regarding FPV/UAV flight.
ImmersionRC accepts no responsibility for property damage, parts damage, model damage, or personal
injury due to the misuse of the EzUHF, or any other ImmersionRC product.
Radio Licensing
The EzUHF R/C control system transmits on radio frequencies which may require a license for use.
The specific band of frequencies is firmware-dependent, and in some cases may be tailored to meet a
retailer/distributor’s requirements.
The default band used is 433-435MHz, which falls in the 70cm Amateur Radio band.
Because of this, this product requires an Amateur radio (or similar) license to use in most parts of the
world.
Please check your local legislation before using this product!
EzUHF Transmitter
Powering the transmitter
The EzUHF transmitter has two flexible power options. Both of which may be used for additional
redundancy:
1) Power supplied via the 4-pin mini-din connector.
In the case where the transmitter is connected to a futaba radio, with 9.6v, or 3s Lipo power
source, this is the preferred method of powering the transmitter.
2) Power supplied via the DC power jack.
In cases where the R/C transmitter either doesn’t provide power via its trainer connector, or
when a lower voltage is available (2s radios for example), it is preferred to power the EzUHF via
the DC power jack.
The power jack is center-pin positive, 2mm internal pin, 5.5mm outer diameter.
A suitable plug is Mouser #502-S760BK
NOTE: The EzUHF transmitter may safely be powered via both connectors simultaneously, even if two
different voltages are presented.
ImmersionRC | EzUHF R/C Control System
5
As an example: Take the case of a R/C transmitter which uses a 2s LiPo pack. The EzUHF will emit slightly
less power than specified (approx. 25dBm on 8v, vs. around 29dBm on 11.1v) when powered this way.
In most cases this power difference is insignificant, for buzzing around the local flying field, this is a very
reasonable power level.
If full power is desired in this case, a 3s LiPo pack (or equivalent) can safely be connected to the DC
Power jack, providing both higher power, and redundancy (no power will be consumed from the R/C
transmitter’s battery until the external pack is either drained, or removed).
Binding
Each EzUHF Transmitter and receiver must be ‘bound’ together, before they may be used, as is the case
with just about all of the 2.4GHz systems on the market today.
The binding process teaches the receiver several pieces of information:
1) The transmitter’s unique ID, and therefore its pseudo random hopping sequence
2) The precise frequency difference between the transmitter and receiver (caused by crystal
tolerance)
3) The precise frame-rate emitted by the R/C Tx
Note that point 3 does mean that rebinding is required if the EzUHF transmitter is switched between
different R/C transmitters, especially those with different frame rates.
For more advanced binding, see Appendix A: Binding multiple transmitters to a single receiver.
The binding procedure is as follows:
1) Connect suitable antennas to both the EzUHF Tx, and Rx and place them within 1m of each
other
2) Connect the EzUHF Tx to the R/C Transmitter, switch to low power mode, hold down the
pushbutton, and turn on the radio.
3) As soon as a periodic beeping starts, let go of the button.
4) Apply power to the receiver, and within 10 seconds, hold down the binding button on the
receiver. After < 1 second the LED should extinguish, and shortly after, it should flash 3 times,
indicating binding success.
If instead, the LED flashes 6, or 10 times, quite quickly, then binding failed, and must be reattempted.
NOTE!: The Bind switch on the 8 channel ‘dual board’ receiver is accessed between the two
boards, from the hole beside the servo connectors (it is not hidden under the ‘BIND’ text on the
label).
5) Power down the Tx, and Rx. Binding is complete.
NOTE: The 10 second limit on the receiver ensures that the receiver can never enter binding mode
accidentally during flight, if its button is accidentally pressed.
ImmersionRC | EzUHF R/C Control System
6
See the advanced section, on how to bind multiple transmitters to a single receiver.
Failsafe
If, for any reason, the UHF link is broken, the receiver will wait for approximately 1 second for the link to
be restored, and then will enter failsafe mode.
The failsafe servo positions are programmed using the button on the transmitter.
To set this up, two phases are recommended.
1) With the plane on the ground, and servo positions neutral, throttle cut, hold down the
transmitter’s bind/failsafe button until the transmitter beeps. This will set a reasonable default
failsafe ready for the first flight
2) With the plane in flight, set the controls in a suitable position for the failsafe, and re-program
the failsafe. In most cases, ‘suitable position’ means throttle cut, and a gentle turn radius, to let
the plane circle gently until it lands, but of course every application is a little different.
Power Level control
The toggle-switch on the top of the EzUHF Tx is used to switch between high and low power modes.
Even if full feedback of uplink status is available on the EzOSD display, it is highly recommended to fly in
low-power mode most of the time, switching to high-power mode if required.
The difference in power levels between the two modes is approximately 6dB, which corresponds to a
factor of 2 in range, ensuring plenty of margin.
Range Testing
Before any flight it is highly recommended to perform a range test on the ground. For this, use at
minimum the low-power mode, or more ideally, attenuate the transmitter output using an SMA
attenuator for the range test (NOTE: Do not forget to remove the attenuators before the flight!!!!).
A 20dB SMA attenuator, easily sourced on Ebay, is a good choice for this.
The transmitter does include a range-test feature, which drops power to approx. 13dBm (20mW).
To access this mode, switch from High to Low power mode with the bind pushbutton pressed.
WARNING: Do not forget to cycle Tx power before flying to leave range-testing mode.
ImmersionRC | EzUHF R/C Control System
7
Transmitter Compatibility
The PPM input circuit of the EzUHF Tx is designed to support a large range of transmitters, with PPM
input voltages ranging from 3.3v, all the way to 9.6v or more.
Most of the in-flight testing was performed using Futaba systems, which is used by the system's
designers. This is therefore the preferred radio for use with the EzUHF link.
Support for other radios will be added as further testing is done.
The EzUHF uses standard 4-pin Mini-DIN connectors, for the R/C transmitter link (PPM-In), and the link
to the Headtracker (see below: Cabling the TrackR2 to the EzUHF Transmitter).
These connectors are the same as those used on the TrackR2 headtracker, with the same pinout.
These connectors are also the same as those used by the popular S-Video standard, which makes finding
pre-molded connectors and cables quite easy. The S-Video cables have Chroma/Gnd, and Y-Luma/Gnd
as two twisted pairs, these correspond to Pwr/Gnd, and PPM In/N/C, which won't cause any problems.
Note that the S-Video extension cables (Male -> Female) may be used as extension cables, but cannot
be used to connect the TrackR2 to the EzUHF Transmitter (see below)
S-Video pin-out:
PPM Input & Head-Tracker input pin-out:
As viewed looking at the female connector on the UHF Tx.
Loading...