Q: How many wireless sensors can be supported by a MonnitLink™ Wireless Gateway?

A: All MonnitLink™ wireless gateways can support up to 100 sensors each. To expand a network beyond 100 sensors, simply add another wireless gateway to the network and continue expanding.

 Q: Can I add additional sensors to the wireless sensor network at a later time?

A: Yes. You may expand your network as needed, up to 100 sensors per wireless gateway. You can add an unlimited number of wireless gateways, so you are not limited to the amount of wireless sensors you can have on your account.

 Q: What frequencies do the wireless sensors communicate on?

A: Monnit’s wireless sensor networks currently operate on the ISM 900MHz (902-928MHz) band as well as 868MHz and 433Mhz bands.

 Q: How is sensor data protected during wireless transmission?

A: The wireless communication technology developed by Monnit provides several features to help protect your data in transit. Our proprietary sensor protocol uses very low transmit power and requires specialized radio equipment to operate. Typical wireless devices that operate on non-proprietary communication protocols (Wi-Fi, Bluetooth, Zigbee) operate using different frequency bands so they can't be used to eavesdrop on the radio communications from the Monnit family of sensors. In addition we use a robust packet tampering evaluation routine to ensure that traffic wasn't altered between the sensors and the gateways. This enables us to check for well-formed data packets that only originated from Monnit enabled devices. To further protect data we have algorithms that protect against spoofing and re-transmission of wireless data packets. This is included with the best in class range and power consumption protocol developed for Monnit wireless sensor systems.

 Q: What is the average life span of the battery in the wireless sensors?

A: The life span of the battery is dependent on a number of factors: how frequently the sensor transmits data (heartbeat), how far the sensor is from the wireless gateway and obstructions that could cause difficulty in sending data (farther distance and obstructions require that the radio to operate at longer intervals to send and receive data).
Monnit estimates through normal usage a sensor in the field should last ~ 1-2 years before it needs to be replaced.

 Q: What should I do with my wireless sensor when the battery dies?

A: With our standard sensors, once the coin cell battery has been depleted, you can change the battery by peeling the sticker away from the battery slot then use a paper clip or small screwdriver to push the battery out and replace with a new CR2032 coin cell battery. With AA battery type sensors, simply slide the battery compartment door open to access the batteries. We encourage you to recycle all old batteries.

 Q: What do I need to have in my possession to run a Monnit wireless sensor network (WSN)?

A: To deploy a standard Monnit wireless sensor network, you will need a MonnitLink™ wireless gateway and any Monnit wireless sensor(s) that are needed for your application.

If using Monnit Wi-Fi (MoWi) sensors, no Monnit wireless gateway is needed. You will need to have an existing Wi-Fi network in range of the Wi-Fi sensors for them to communicate with the iMonnit online sensor monitoring system. 

If using a MonnitLink™ USB wireless gateway, you will need to have a Windows PC with Internet access to transmit the sensor data to iMonnit, the online sensor monitoring system. (Alternately you can use Monnit Express to gather sensor data locally without an internet connection.

Q: Should I expect interference from other wireless networks (Wi-Fi, walkie talkies, cordless phones, cellular phones, radios, etc.) operating in the vicinity of my Monnit wireless sensor network (WSN)?

A: No. Monnit's wireless sensors currently operate in the 900Mhz ISM band. Most wireless sensors today operate in the crowded, 2.4Ghz space where cell phone, WiFi networks, wireless telephones, and many wireless accessories for networks and PCs operate.

Monnit chose the 900Mhz frequency for its performance characteristics (much better range through obstacles than 2.4Ghz) and "openness" of the frequency. Operating at 900Mhz limits the ability to deploy sensors to a specific region (North America only).

The chipset used by Monnit for our wireless sensors also supports 868MHz as well as 433MHz. Support for international markets will utilize these two frequencies for best performance.

 Q: Do the gateways look for a clear RF channel when it is powered up? Can it switch channels if noise or interference is high?

A: During testing of sensor networks prior to shipping of the product, the networks are formed and the gateways choose a channel to transmit on. When you receive the product, that channel stays constant until reset by the user. 

If you want to have the gateway search for the most clear channel in your environment, you will need to follow these steps: 

USB Wireless Gateways

For iMonnit users:
1. Start the iMonnit gateway software.
2. Insert the USB dongle and wait for the network to go active.
3. Select "Reset/ Reform Network" within the gateway software and wait for 30 seconds.
4. When network has reformed, begin putting the batteries in the sensors.

For Monnit Express users:
1. Start the Monnit Express software.
2. Insert the USB dongle and wait for the network to go active.
3. Go to the pull down menu titled "File" and select "Reset/ Reform Network," wait for 30 seconds.
4. When network has reformed, power cycle the sensors by removing batteries, waiting 30 seconds then reinsert. If you do not power cycle the sensors, they will automatically come back online, after entering link mode (two missed communications with the gateway).

Ethernet and Cellular Wireless Gateways
1. Launch a browser and log into iMonnit.com
2. Click the "View Gateways" link.
3. Click into the row where the gateway is to drop down the gateway details.
4. For Ethernet: Click the "Edit tab, then the "Commands" tab and click the "Reform" link.
5. For Cellular: Click the "Edit" tab, then click the "Reform" link.

Your sensor network is now operating on the most friendly RF channel available in your area.

 Q: What are the voltage input requirements for the OEM/RF wireless sensor circuit boards?

A: Monnit / OEM wireless sensors require 2.0 - 3.6 VDC max.

Q: What is the power draw of a wireless sensor?

A: In sleep mode the sensor consumes .5µ Amps and during transmit the sensor consumes 35 mA.

Q: What happens to my wireless sensor network if using a USB wireless gateway and the host computer goes into sleep mode or is powered off for some reason?

A: If the MonnitLink™ wireless gateway is unable to receive transmissions from the sensors due to the PC being off or asleep, the sensors will continue to try and link with the gateway (two times by default). If it is unable to link to the gateway it will enter “link mode” where it will search for another nearby gateway. If no gateway is found, the sensor enters "power save" mode, and will sleep for two hours before entering link mode again, and search for a gateway. This process will continue until the sensors find a gateway to communicate with.

Note: While the gateway is off, no data is being collected and no notifications can be transmitted.

 Q: Does the USB Wireless Gateway need to be plugged directly into the computer, or can I plug it into a USB port expander?

A: If you are using an unpowered USB port expander/hub, the MonnitLink™ USB Gateway will not operate properly. To insure best performance of the Monnit Sensor Network, plug the USB gateway into a powered port expander, or best yet is to plug the USB gateway directly into a USB port on your computer.

 Q: How can I extend the range of my wireless sensor network ?

A: The range between Monnit wireless sensors and wireless gateways can be extended by using a Monnit wireless range extender. A Monnit range extender can double the range between the sensors and gateway. Multiple range extenders can be used together to give even further range. 

Note: If using more than one range extender, the sensor data traffic doubles at each unit in the communication chain. This limits the number of sensors supported by the last repeater.

 Q: What are the size of the data packets being transmitted by the sensors to the gateway?

A: The application data is 18 bytes in length and the total TX packet size is 40 bytes.

Q: How do I mount the wireless sensors for my particular application?

A: Monnit has provided a number of mounting options for the sensor technology. In the deployment kits we have included screws and double-sided tape. These options should allow you to mount the hardware to most any type of material.

Q: My temperature sensor is giving me a reading of -1767.8F (-999.9C), what does this mean?

A: A reading of -1767.8F signifies that the thermistor wires have broken or the battery has not been fully inserted causing a short between the thermistor leads on the sensor board. If this happens; try removing the battery, wait 60 seconds then re-insert the battery making sure to push the battery all the way to the back of the sensor housing. When the sensor comes back online check the reading to see if it has been corrected.

Q: How do my wireless sensors connect to the monitoring software on the internet?

A: Each Monnit wireless sensor comes ready to connect to the MonnitLink™ Wireless Gateway upon power up with the exception of Wi-Fi sensors which connect driectly to your internet router. 

If using a USB gateway, make sure that the USB Driver has been installed and the Monnit Gateway Software is installed and running, then simply insert the USB gateway into the PC. Once the gateway establishes a connection with the iMonnit™ online wireless sensor monitoring system and communicates with the Monnit servers, simply insert the batteries into their holder on each sensor. The sensor will power up and connect to the wireless gateway and communicate with iMonnit™, assigning each sensor its own unique id number.

Q: Will a wireless sensor notify me when I need to change the battery?

A: Each time the sensor transmits data to the iMonnit online sensor monitoring system it reports the battery power as well. Notifications can be set to alert you by email or text message, when a sensor's battery is about to expire.

 Q: I purchased a voltage detection sensor. What is the proper way to connect this to my power source?

A: If a voltage type sensor is not connected to the power source properly, it will appear that the sensor does not work. Please follow the wiring diagram below to ensure proper performance and detection.

Monnit Voltage Sensor Wiring Diagram

Q: Do Monnit gateways support HTTP proxies?

A: The Ethernet Gateways won’t be affected by many of the HTTP proxies, but if they are affected, they will need to be whitelisted. If a proxy works at the socket level, it will have to be whitelisted.