Wireless Endpoint


The ioBridge Wireless Endpoint provides wireless extension for digital inputs and outputs (IO) and serial data on the Gamma Ethernet Gateway and are designed for a wide range of applications including:

  • Remote monitoring and data logging.  Each Endpoint includes built in temperature and humidity sensors and are compatible with a wide range of third-party analog, current, and pulse sensors.
  • Alerting
  • Remote control
  • Local control based on sensor inputs. The system can be easily configured to operate local equipment for example based on sensor readings.

The Wireless Endpoint PROs integrate seamlessly with the way the ioBridge web gateways work to enable wireless monitoring and control.  The following diagram shows how the Wireless Endpoints fit into the overall system.  IO ports on the Wireless Endpoints can be monitored and controlled via a web browser or mobile app anywhere in the world.  The Wireless Gateway and the Wireless Endpoints can also be set up to run autonomously to perform local control without internet connectivity.  The Wireless Endpoints are designed to run for up to a year off AA batteries and Solar and Mains powered options are also available.



  • General purpose professional wireless extension of IO for ioBridge wireless gateways (such as the Gamma with XBee)
  • Easy to configure and directly compatible with ioBridge’s existing gateway functionality and cloud services, including
    • Data logging
    • Remote monitoring and control
    • Alerting
    • Free Web and Smart Phone interfaces
    • Local “Rules and Actions” to perform local logic
  • Uses XBee Series 1 radios in point-to-multipoint mode
    • XBee radios automatically programmed using the wireless gateway (manual programming of the XBee settings is not required)
    • Compatible with XBee Series 1 PRO or standard radios with either chip, wire or external antenna options
  • Up to 1 mile outdoor range using the XBee PRO variant
  • Up to 12 Endpoints per wireless gateway (such as the Gamma with XBee)
  • Highly flexible and general purpose with multiple modes of operation
  • Includes an internal temperature sensor with optional internal humidity sensor
  • 5 volt compatible inputs and outputs (IO) compatible with a wide range of 0-5 volt or 0-20mA sensors
  • IO includes
    • one 10-bit analog input (or 0-20mA when selected)
    • one digital input
    • one digital output
    • one 8-bit 0-5 volt analog output
    • 9600 baud serial UART
    • Internal latchable relay (NC, C,NO) that corresponds to digital output setting
  • 10 second or 121 second update rate depending on power source
  • Multiple power options including:
    • Two AA with typical life of 1 year
    • Solar panel with Polymer Lithium Ion battery
    • External 5VDC power adaper
  • 128-bit over the air encryption unique to each wireless gateway
  • Firmware upgradable over the web
  • Static protected inputs
  • Dimensions of 3.2″ x 5″ x 1″ including external connectors (but not including the external antenna)
  • Wall mount plate available
  • Can be mounted in water proof third-party enclosures for outside operation.
  • Operating Temperature -40C to 70C non-condensing.

How it Works

The Wireless Endpoints are designed to be compatible with the way the ioBridge system works.  In particular local Rules and Actions, Data Logging, Alerting and Dashboards Widgets can be used with the IO on the Wireless Endpoints.  This compatibility has been achieved by mapping IO ports on the wireless gateways to sets of variables in the Gamma web gateway.  The up to 48 variables in the Wireless Gamma Gateway are keep in sync wirelessly with the IO on the Wireless Endpoints and Rules and Actions and Widgets may be mapped to the variables and hence the Wireless IO.  The mapping of the Wireless IO and the Gateway variables is illustrated in the following diagram.

  The Gamma Ethernet Gateway requires the addition of a Gamma XBee Adapter to communicate with the Wireless Channels.  Up to 12 Wireless Channels can be used per Gamma Ethernet Gateway.

Wireless Endpoint Configuration and Operation

Power, Controls, and IO

The following illustration shows the inputs, outputs, connectors, and switch controls for the Wireless Endpoint PRO with the external antenna option.



Standard IO

Each Wireless Endpoint has a number of standard IO ports are that a superset of the IO ports available on the channels provided with most ioBridge web gateways like the IO-204. Like a typical ioBridge Web Gateway each Wireless Endpoint has the following IO:

  • 0 to 5 volt Analog Input (AI)
  • 0 or 5V Digital Input (DI)
  • 0 or 5V Digital Output (DO)

as well as a serial UART with transmit (Tx) and Receive (Rx) terminals.  The serial USART on Wireless Endpoint PROs operates at 9600 baud (8N1).

Analog Input (AI)

The Wireless Endpoint analog input is 0 to 5 volts and has a resolution of 10 bits. The 0-5 volt input is represented as a value from 0-1023 (10-bit).  The 0-5V analog input can also be used to measure 0-20mA but switching an internal 250 ohm resistor in parallel with the 0-5V input. This is achieved using the DIP switch shown below:

Digital Input (DI)

The Digital Input is connected to a microcontroller pin and reads a 0 or low if the voltage is less than 0.8VDC and high or 1 if the voltage is greater than 2VDC.

5 Volt Output (5V)

The 5 volt output is a 100mA maximum switched supply controlled by the Endpoint.  When running from batteries the 5V output is only switched on momentarily to power sensors while readings are being taken.  The availability of the 5V output is summarized under Modes of Operation below.

Extended IO

Differences exist between the standard IO on Wireless Endpoints and the IO on most ioBridge Ethernet web gateways.  On web gateways the DI is pulled high to 5V with a 27k resistor while the Endpoint pulls the DI low with a 100k resistor for power saving reasons.  The DO on the Wireless Endpoint is a different too and is best described using the following circuit diagram.

Note the additional latchable relay connections (NC,C,NO) that are controlled by the same variable that sets DO.  The latchable relay is ideal for battery operation as it draws no power after it has been switched and remains in the same state until it is switched again.  The specifications of the latchable relay are as follows and is ONLY recommended for low voltage switching.

  • Nominal switching capacity 1 A 30 V DC (resistive load)
  • Max. switching power 30 W (DC) (resistive load)
  • Max. switching voltage 110V DC
  • Max. switching current 1 A
Analog Output (AO)

The Wireless Endpoint provides a 0-5 volt analog output which is a capability that is not available on the standard ioBridge web gateways.  The output voltage is mapped to gamma variables and the value of the gamma variable corresponds to the output voltage in millivolts DC.  For example, a variable value of 2500 will provide an output voltage of 2500 mV or 2.5V DC.  Note that the resolution of the output voltage is 8-bit.

Modes of Operation

The Wireless Endpoints are designed to be multi-purpose devices.  Built into each Wireless Endpoint is a temperature sensor.  As an additional option built-in humidity sensing is also available.  Each Wireless Endpoint can currently operate in one of six modes.  This makes the Wireless Endpoints highly flexible.  The operating mode of a Wireless Endpoint is selected using the DIP switch paddles shown in the diagram below. (Note that the numbers marked on the DIP switch are not the same as the numbers below and should be ignored.)   The relationship between DIP settings and mode is shown below. Each mode has two states – battery powered or mains powered.  The operation in each of these states may be different because when running off a battery certain modes of operation are not desirable for long battery life.  When running of battery power the Wireless Endpoint is in a low-power consumption sleep state and wakes up every two minutes or so to sync with the wireless gateway before going back to sleep.  When the Wireless Endpoint is powered by the mains or powered by sufficient solar energy the Endpoint does not need to go into a low power state and can communicate more frequently allowing modes such as serial communication to operate.

Mode 1 (Internal Temperature, Humidity*, Analog Out, Digital Out and Relay)

Mode 1 is designed to be the default mode.  In this mode the Wireless Endpoint behaves as a wireless temperature sensor and optionally also a wireless humidity sensor.  The AI and DI inputs on the Wireless Endpoint are disabled in this mode and the values from the internal sensors are mapped instead.  The format of temperature and humidity readings mapped to the wireless gateway variables is as follows:


A reading from -40C to +125C (theoretical since the Endpoint is not designed to work above 80C) in tenths of Kelvin.  Kelvin was chosen since the value can never be negative.  Tenths was chosen to provide suitable resolution. For example, a reading or variable value of 2953 sent to the gateway corresponds to: 2953/10 or 295.3K.  This can be converted to F or C using Expression Builder and the following equations:

Temperature in C = VariableValue/10 - 271.15 = 2953/10 -273.15 = 22.1C
Temperature in F = (VariableValue/10 - 271.15 ) * 1.8 + 32 =  (2953/10 - 271.15 ) * 1.8 + 32 = 71.9F
External Temperature

From version 5 of the Endpoint firmware it is possible to connect a Dallas DS18B20 1-wire temperature sensor to the Endpoint.  The Endpoint automatically detects the presence of the external sensor and replaces the internal temperature reading with the temperature reading from the Dallas DS18B20.  The DS18B20 is connected to the Endpoint as follows:

Endpoint DS18B20
Humidity or Digital Input

Depending on the Endpoint model either Humidity or DI is measured in Mode 1.  If humidity is included, then the DI is disabled, and the the variable value represents the humidity in percent.  For example a variable value of 35 is 35% humidity.

Digital Output, Analog Output, and Latchable Relay

The Digital Output (DO), Analog Output (AO), and Latchable relay IO is kept in sync in Mode 1.  The updates are approximately every 10 seconds when powered and every 2 minutes when battery operated.

Mode 2 (Analog In, Digital In, Analog Out, Digital Out and Relay)

Mode 2 most closely mimics the IO operation of the channels in an ioBridge gateway.  In this mode the DO, DI, AI and AO terminals are kept in sync with matching variables on the gateway.   The latchable relay is also active. The updates are approximately every 10 seconds when powered and every 2 minutes when battery operated.

Mode 3 (Analog In, Pulse In, Analog Out, Digital Out and Relay)

In this mode DI becomes a pulse counting input and the DO, Pulse, AI, AO and relay outputs are kept in sync with matching variables on the gateway.  DI pulses are counted continually for each positive edge (i.e. 0 to 5V pulse).  The cumulative pulse count updates occur approximately every 10 seconds when powered and every 2 minutes when battery operated which ever time comes first.  The pulse count may be reset to zero using the reset button. Note that power is continually supplied to the +5V out in this mode and power used by the +5V out will decrease battery life when operating in battery powered mode.

Mode 4(Analog In, Pulse In, Analog Out, Digital Out, Relay and Encapsulated Serial in “Powered” mode)

Mode 5 operates identically to Mode 2 when battery operated but when in powered mode the Wireless Endpoint sends encapsulated and receives RAW serial messages from the wireless gateway. The serial UART connections are 5 volt levels through the Tx and Rx terminals. The baud rate is 9600, 8 bits, no parity, with one stop bit (8N1) and is idle high. This mode may be used to send serial messages from a dashboard widget or via the serial api. Serial messages sent in the Rx terminal are sent in an encapsulated format and are forwarded to the server. In this mode serial messages sent into the Rx port are sent through to a serial widget and are accessible via the serial api. Note that other than built in XBee CSMA contention there is no other contention handling and other Wireless Endpoints can interfere sending serial messages in this mode. This serial mode is best suited to sending intermittent messages of less than 256 characters.

Mode 5 (Analog In, Pulse In, Analog Out, Digital Out, Relay and RAW Serial in “Powered” mode)

Mode 4 operates identically to Mode 2 when battery operated but when in powered mode the Wireless Endpoint sends and receives serial messages from the wireless gateway. The serial UART connections are 5 volt levels through the Tx and Rx terminals. The baud rate is 9600, 8 bits, no parity, with one stop bit (8N1) and is idle high.  This mode may be used to send serial messages from a dashboard widget or via the serial api. Serial messages sent in the Rx terminal are sent in RAW format (i.e. they are not encapsulated for forwarding to the web interface – see Mode 4 below). Note that other than built in XBee CSMA contention there is no other contention handling and other Wireless Endpoints can interfere sending serial messages in this mode. This serial mode is best suited to sending intermittent messages of less than 256 characters.

Mode 6 (Analog In, Pulse In, Analog Out, Digital Out, Relay and Rangefinder Serial)

Mode 6 is a special mode designed to work with the Maxbotix ultrasonic rangefinders.  Apart from DI, the operation of this mode is identical to the standard Mode 2.  DO, AI, AO and the relay are kept in sync but the DI input is replaced by range readings send by the ultrasonic rangefinder.  The Maxbotix ultrasonic rangefinders sends serial messages representing range in the format: Rxxx or Rxxxx where xxx or xxxx is the range reading in cm or inches depending on the sensor model. The ultrasonic range sensor is connected to the Wireless Endpoint as follows:

A median of 10 serial ultrasonic sensors readings is synchronized with the gateway DI variable.  For example, R245 sent 10 times by the ultrasonic sensor will result in a reading of 245 being sent to DI.  This will happen approximately every 10 seconds when mains powered and 2 minutes when battery operated.  If a sensor is not connected or if the reading is less than 19 or greater than 9998 then no range reading will be sent to the gateway.

Wireless Endpoint IO to Variable Mapping

As shown in the following illustration, the mapping of the Wireless Endpoint is selected using the dip switch on the side of the device.  The first four white paddle actuators (switches) on the right facing the switch are used to set the variable mapping. The Wireless Endpoint maps its Analog Input, Digital Input, Digital Output and Analog Output to sets of four Gamma variables as shown in the following table.  Note that it is possible but not desirable to set two Wireless Endpoints to map to the same set of four variables.   Note that:

  • AI = 0-5VDC Analog value from the Endpoint. (Temperature in Kelvin x 10 in Mode 1)
  • DI = High Low digital value from the Endpoint. 0 or 1 (0 if DI is connected to ground, 1 if DI is connected to 5V). Humidity in percent in Mode 1.
  • DO = Value to the Endpoint. Sets a latchable relay – see DO for details.
  • AO = Value to the Endpoint. Variable value of 0 to 5000 corresponds to 0-5V output on the endpoint. Limited to 5V.


Power Options

The Wireless Endpoint is designed to operate from a number of power sources including two AA batteries, a 6VDC solar panel, or an external 5VDC power adapter.  Depending on the power source the Endpoints will update either every 121 seconds or every 10 seconds.  As shown in an earlier diagram, the power switch is located in the battery enclosure.  The Wireless Endpoints trade-off flexibility with power consumption and although they have a typical battery life of approximately one year in mode 1 with no external sensors, they are not primarily designed for ultra-long life using batteries.  For indoor applications mains power is recommended and for outdoor applications solar and lithium is recommended.  Note that by using a third-party 6 volt DC power supply the solar mode can be used indoors with a lithium battery providing battery backup in the event of power failures.

AA Battery

The Endpoint enclosure can accommodate two AA batteries that have an expected life of up to a year depending on mode of operation and external loads.  Batteries such as the Lithium/Iron Disulfide (Li/FeS2) from Energizer are recommended. To conserve energy consumption and to extend battery life when operating off AA batteries, the Endpoints operate in a mode where they sleep most of the time and wake up every 121 seconds for typically less than 1 second to take readings, communicate with the wireless gateway, set IO and then go back to sleep.

Solar Charger and Lithium Ion Battery

The AA battery enclosure can also accommodate a 3.7V 850 mAh Polymer Lithium Ion Battery that plugs into a JST header on the PCB.  The Endpoint includes an on-board Lithium Ion battery charger designed to  charge the battery using a 6VDC solar panel.  With standard settings, the Endpoint will update every 10 seconds when operating off solar.  If the Lithium Ion battery drops below 3.7 volts the Endpoint will automatically switch to a 121 second update to conserve power.

External 5VDC Power Adapter

An additional power connector is included to enable the Endpoint to operate using a 5VDC mains power adapter.  When powered by the 5VDC adapter, the endpoint will update every 10 seconds.

Ethernet Gateway Configuration

As shown below, configuring the Gamma Ethernet gateway requires that an XBee Adapter with an XBee radio be mounted in the Ethernet Gateway.

The XBee modules are configured to operate at 57600 baud and so the Gamma must be set as follows using the web interface to enable the serial connection between the Gateway and the XBee radio.

In addition in the Wireless Endpoints tab, wireless must be enabled.

XBee Configuration with the Gamma

The Wireless Endpoints are designed to operate with Series 1 (S1) XBee or XBee PRO radios configured in serial line replacement or Transparent Mode at 57600 baud.

Compatible models include:

XBee 802.15.4 Low Power Modules North America: International:
XBee 802.15.4 low-power module w/ wire antenna XB24-AWI-001 XB24-AWI-001
XBee 802.15.4 low-power module w/ PCB antenna XB24-API-001 XB24-API-001
XBee 802.15.4 low-power module w/ U.fl connector XB24-AUI-001 XB24-AUI-001
XBee 802.15.4 low-power module w/ RPSMA connector XB24-ASI-001 XB24-ASI-001
XBee-PRO 802.15.4 Extended Range Modules North America: International:
XBee-PRO 802.15.4 extended-range module w/ wire antenna XBP24-AWI-001 XBP24-AWI-001J
XBee-PRO 802.15.4 extended-range module w/ U.fl connector XBP24-AUI-001 XBP24-AUI-001J
XBee-PRO 802.15.4 extended-range module w/ RPSMA connector XBP24-ASI-001 XBP24-ASI-001J
XBee-PRO 802.15.4 extended-range module w/ PCB antenna XBP24-API-001 XBP24-API-001J


Note that the U.fl version and the RPSMA versions require external antennas.  The RPSMA version with RPSMA antenna (A24-HASM-450) is directly compatible with the Endpoint enclosures but the U.fl version will require an external mount for the antenna.

Using the Gamma, each XBee can be automatically configured and programmed with a private encryption key.  The following steps must be performed on each XBee that will go into an Endpoint as well as the XBee that will reside in the Gamma.

  1. Gather all the XBee module that will be used with this Gamma.
  2. Remove power and the Ethernet connection from the Gamma.
  3. If the Gamma is in a case, remove the cover.
  4. Insert the Gamma XBee Adapter into the expansion slot.
  5. Insert an XBee into the adapter socket.
  6. Apply power to the Gamma. (But do not attach the network cable!)
  7. Press the Gamma’s Link button twice within one second.
  8. The Gamma’s LED display should slowly begin to count from 1 to 6 as it is configuring the XBee. Don’t worry if it skips some numbers.
  9. The LED display should reach 6 and then go blank when the process is finished.
  10. Remove the XBee and reinstall it in an Endpoint.
  11. Repeat Steps  5 through 10 until all the XBees have been configured.
  12. Don’t forget to configure the XBee that will stay in the Gamma.
  13. Replace the Gamma’s cover, apply power and reconnect the Ethernet cable.

Alternatively the Digi X-CTU software can be used to configure the XBees with an XBee to USB adapter.  The following text can be saved to a file and uploaded to the XBee using X-CTU:


Note that the XBees are set to operate in Encrypted Mode and if X-CTU is used to program the XBee a user generated 16-byte Encryption Key will need to be added using the ATEE and ATKY commands.  Please see the XBee documentation for more information.

Other networking modes are also possible but have not been tested

Endpoint Range Testing and Gateway Communication

Endpoints may be placed in “range testing” mode by powering on an Endpoint while depressing the Reset button at the same time.  The Endpoint will perform the standard start up sequence and will then enter Range Testing mode for 2 minutes.  The Endpoint will attempt to communicate with the gateway once every second and will return a “Happy Beep” if successful and a “Sad Beep” if not.  This can be used to test the range of the Endpoint during installation.  After 2 minutes the Endpoint will return to the mode set by the dip switches.

This mode is also useful to tell if the Endpoint is able to communicate with the gateway.  It may be used for example to verify that the XBee settings are correct.

Beep Sounds

The Endpoints include an internal buzzer and generate tone sequences to aid in identifying operation.  Typical beeps sequences are described below. Audio recordings of useful sequences may be heard by clicking on the mp3 links below.

Endpoint startup sequence in Mode 6

The sequence is as follows:

  1. “Happy Beep”
  2. “count of one 1/2 second beeps for each mode (i.e. one beep for Mode 1, six beeps for Mode 6)”
  3. “Happy Beep”
  4. “Ten short double beeps (allowing XBees to settle)”
  5. “3 second delay”
  6. “Happy Beep (if able to successful communicate with the onboard XBee.  This verifies that the XBee baud setting is correct but does not verify communication with the gateway. Use Range Testing for that.)”

Endpoint mode 6 startup sequence (mp3 audio file)

Endpoint startup sequence in mode 1 when unable to communicate with the XBee

The sequence is as follows:

  1. “Happy Beep”
  2. “count of one 1/2 second beeps for each mode (i.e. one beep for Mode 1)”
  3. “Happy Beep”
  4. “Ten short double beeps”
  5. “3 second delay”
  6. “Sad Beep”

Endpoint mode 1 startup no xbee communication (mp3 audio file)

Endpoint Range Test beeps starting with success and then going out of range

  1. “Startup sequence”
  2. “11 happy beeps while in range of the gateway (as an example happy beeps will continue for up to 120s while in range)”
  3. “4 sad beeps while out of range of the gateway (as an example)”

Endpoint range test (mp3 audio file)

Beeps during upgrade

The following is a recording of the short beep tones made while an Endpoint is updating the firmware.

Endpoint upgrade beeps (mp3 audio file)

This is followed by the startup sequence above.


Endpoint Firmware Updating

The firmware in all the Endpoints connected to a particular gateway may be updated over-the-air.  The steps to do so are as follows:

  1. Compare the Firmware Version number reported by the Endpoints with the Firmware Version available in the Wireless Gateway (i.e. A Gamma with an XBee adapter) on the Wireless Endpoints tab.  If a newer firmware version is available then it is possible to update the Endpoint firmware.
  2. Ensure that the Endpoints that you wish to update are connected by checking the Wireless Endpoints have recently connected.  REFRESH the page to see the latest information.
  3. If there is newer firmware available click the Update button under Wireless Gateway on the Wireless Endpoints tab.
  4. Wait for the Endpoint firmware to be saved to the Wireless Gateway

Please note the following:

  1. It is not possible to select only a subset of Endpoints connected to a gateway to be updated.
  2. When the Wireless Endpoints connect to the gateway to send and receive messages they will automatically determine that new firmware is available.
  3. It is not necessary to disconnect the I/O but note that during the update process the Endpoint will not operate.  The Endpoint will also reboot at the end of the updating process.
  4. Each Endpoint will be sequentially updated typically in the order that they connect.  Only one Endpoint is updated at a time.   The updating process typically takes less than a minute per Endpoint.
  5. Note that if Endpoints are sleeping then the entire update process will be delayed by the time taken for Endpoints to wake up and determine that new firmware is available.
  6. During the update process the Endpoint remains on and makes short beeps.  If the upgrade is successful a “happy beep” sound is made.
  7. The next time the Endpoint connects to the gateway the firmware version on the Wireless Endpoints tab will update to the new version.  This may be used to verify which Endpoints have been updated.  REFRESH the page to see the latest information.

Endpoint Firmware Changes

Version 5 changes:

  • Send status message immediately on mode change
  • Added ability to use DS18B20 external sensor
  • Changed Lithium Poly operation to update at 10 second rate while over 3.9 volts regardless of solar level
  • Added DS18B20 external temperature option
  • Additional status information sent
  • Added 500ms to power on in battery mode to allow analog sensors to settle