The Guppy LoRaWAN provides a number of configurable parameters, to allow its behavior to be tailored to specific applications. Factors affecting the configuration you might choose include:
- How many messages per day your network will allow
- How often you intend to change the batteries, and the type of batteries in use
- How detailed a bread-crumb trail you require, or the required time between updates
How The Guppy Connects (OTAA)
By default, the Guppy connects to a local LoRaWAN network using Over The Air Activation. Each Guppy is provisioned with:
- A read-only DevEUI - a 16 digit code uniquely identifying the Guppy (printed on the label)
- A configurable AppEUI - a 16 digit code uniquely identifying the website that data will be sent to
- A configurable AppKey - a 32 digit code that authenticates the Guppy to the website and network server
- The default AppEUI is 70-B3-D5-70-50-00-00-01
- Each Guppy is provisioned with a random default AppKey
- A configurable Region and Channel Mask
- The channel mask is used in the US and ANZ regions, to set the network frequencies
- Other regions don't need the channel mask, as all their networks use the same OTAA frequencies
Once the region has been configured, the Guppy will attempt to join local networks by transmitting join requests. Any network that hears the join requests and has knowledge of the Guppy's DevEUI, AppEUI and AppKey, will allow the Guppy to join the network and transmit data.
Once joined, Guppy repeats the OTAA process once a week by default. This renegotiates encryption keys for enhanced security, and ensures continued operation in the event of a network losing the keys (for instance, if the device is mistakenly deleted).
How The Guppy Connects (ABP)
The Guppy can also be configured to connect using Activation By Personalization. When using ABP, each Guppy must be configured with three additional numbers:
- A configurable DevAddr - an 8 digit code identifying the Guppy to the network
- A configurable NwkSKey - a 32 digit code that authenticates the Guppy to the network server
- A configurable AppSKey - a 32 digit code that authenticates the Guppy to the backend website and network server
ABP allows a LoRaWAN device to connect without exchanging the usual join request and join response, which can save on downlink bandwidth, and allow the device to work when downlink reception is difficult. However, in LoRaWAN 1.0, the ABP mechanism is somewhat problematic. It either suffers from a lack of security (if you configure your device to reset it's uplink frame counts when it resets), or difficulty with configuration (if you don't reset the frame counts, and are in a region requiring dynamic channel configuration). These issues are beyond the scope of this document, so we recommend that you use OTAA unless you are confident you understand the implications of ABP.
How The Guppy Locates
The Guppy uses an accelerometer to detect movement, allowing it to decide when an asset is in-trip, and when it is stationary. This allows it to schedule the transmissions as infrequently as possible, to maximize battery life. You can configure the Guppy to transmit a status update:
- Periodically (ie. 24-hour heartbeat)
- At the start of a trip
- During the trip
- At the end of the trip
- During after-hours trips
- When the 'Man Down' status changes
- When a Tilt trigger goes off
For longest battery life, the Guppy can be configured to ignore movement and simply transmit a status uplink once per day. If you need lower latency updates, the next step is to enable transmissions at the end of trips. Finally, full tracking is obtained by enabling the in-trip transmissions.
How The Guppy Uses LoRaWAN Airtime
LoRaWAN devices can transmit at various data rates, usually denoted DR0, DR1, DR2, and so forth. The lowest data rate (DR0) takes the longest to transmit, but has the longest range. As the data rate goes up, the range goes down a bit, and the transmission time goes down a lot. Guppies can be configured to use a particular data rate, or a range of data rates (ie. DR2-DR4). Lower data rates will have the longest range, but also use the most battery power and airtime. When configured to use a range of data rates, the Guppy spends an equal amount of airtime using each data rate. The Guppy also has optional Adaptive Data Rate support, which allows the network server to intelligently control the data rate.
There are several factors limiting the maximum transmission rate of a Guppy:
- Radio regulations may limit the transmission time
- In Europe the law limits you to 36 seconds of transmit time per hour on most frequencies
- Whereas in Australia there is no legal limit
- Networks may limit the transmission time, to prevent congestion
- The Things Network for instance limits you to 30 seconds of transmit time per day
- At DR0, this gives you 25 messages with 100% range
- At DR1, this gives you 45 messages with 75% range
- At DR2, this gives you 90 messages with 50% range
- At DR3, this gives you 181 messages with 37% range
- At DR4, this gives you 323 messages with 28% range
- At DR5, this gives you 647 messages with 21% range
- In America, data rates are all two increments higher, so DR0 corresponds to DR2 in the above list
- Networks may limit the number of messages, for billing purposes
- Your network might require you to pay more for higher throughput
- Battery life may prove to be a limiting factor
- A Guppy can only send around 25 thousand messages at DR0 on one set of lithium batteries
- So for a lifetime of 3 years, the messages per day approximately match the list above
The radio regulations are automatically enforced by inserting delays between messages where required. It is up to the user to configure their Guppy with a low enough transmission rate to meet network and battery life requirements.
How The Guppy is Configured
The Guppy is configurable over-the-air using downlinks. Websites integrating the Guppy can find the complete protocol specification here. Initial configuration of the region and AppEUI, as well as firmware updates, are performed with a plug-in USB adapter, and a Windows configuration app. An adapter can be obtained from your Guppy distributor. The adapter plugs into the four pin connector below the battery compartment.
To read the available parameters, select your adapter from the drop-down list in the top right, and click Start. The configuration tool will read continuously, and display the existing parameters in the center column. To program new parameters and firmware, enter the desired parameters in the right hand column, and check the Program Parameters checkbox. To update the firmwares only, check the Program Firmware checkbox, and leave the Program Parameters checkbox clear.
If you click the DevEUI List button, a list of scanned DevEUIs will pop up. You can hot-plug the adapter into many Guppies in sequence to populate the list. The list is in CSV format, so it can imported into a spreadsheet easily.
The top line in the display shows the DevEUI and version string. In the screenshot above, the DevEUI is 70B3D57050000A09, the firmware version is 220.127.116.11 (product, hardware revision, major, minor). The default AppKey and the effective AppEUI and AppKey can be found in the DevEUI list on the right.
The 'Reset To Default' button in the top of the right column resets the whole right column to the default settings. The 'Existing' button copies the settings from the left column to the right column. The 'Save' and 'Load' buttons open a file dialog, to save or restore the right column to disk. There are many settings, but only a handful require customization. These are highlighted below.
When the Guppy's parameters were last changed.
This selects the radio frequencies to use according to your country. Please be sure to select the correct region, to maintain compliance with your country's radio regulations. Guppies leaving the factory are currently pre-configured for either the European 868 MHz band, or AS923, depending on their hardware type. However, this is subject to change, and in the future the region may be left unset. If the region is unset, the Guppy will not transmit until configured. Otherwise, to prevent the Guppy from transmitting before configuration, click the Start button on the tool, and plug the cable into the Guppy, before inserting the batteries. The region cannot be reconfigured over the air.
This chooses between the default (and recommended) Over The Air Activation, and Activation By Personalization. In OTAA, the Guppy and the network server generate the session encryption keys and device address during a join request / join response exchange. In ABP, you have to generate the encryption keys and device address beforehand, and configure them. There are two different ABP options - Reset Frame Count and Save Frame Count. Reset Frame Count will reset the uplink and downlink frame counts whenever the device is reset. This defeats the encryption entirely, but is required in LoRaWAN 1.0 so that the network server can detect the device reset, and reconfigure the device's channels. If your network doesn't need to detect the device reset and reconfigure the channels, you can select Save Frame Count. In this mode, encryption is not compromised, but there is no opportunity for the network server to reconfigure the device. Future firmwares will upgrade the Guppy to LoRaWAN 1.1, where this reconfiguration problem has been solved.
This identifies the backend website that your data should be sent to. If you leave it blank, the default for the Guppy LoRaWAN (70-B3-D5-70-50-00-00-01) will be used.
This 32 character key authenticates the Guppy with the backend website and network server. If you leave it blank, the Guppy will use a unique random key, which was written to it in the factory. This default key can be read from the DevEUI list dialog, or the label on the box. It is not printed on the Guppy's label. The AppKey cannot be reconfigured over the air.
This 32 character key authenticates the Guppy with the network server. It is only required if Activation is set to ABP.
This 32 character key authenticates the Guppy with the backend website and network server. It is only required if Activation is set to ABP.
This 8 character number identifies the Guppy with the network server. It is only required if Activation is set to ABP.
In the US and ANZ region, you must set this channel mask to select which of the 72 uplink channels your network provider uses. The parameter is one big hexadecimal number, with the lowest channels corresponding to the rightmost digits. For example:
Sub-band 1 uses channels 0-7, and channel 64, so it's mask is 0100000000000000FF
Sub-band 2 uses channels 8-15, and channel 65, so it's mask is 02000000000000FF00
Sub-band 3 uses channels 16-23, and channel 66, so it's mask is 040000000000FF0000
Sub-band 4 uses channels 24-31, and channel 67, so it's mask is 0800000000FF000000
Sub-band 5 uses channels 32-39, and channel 68, so it's mask is 10000000FF00000000
Sub-band 6 uses channels 40-47, and channel 69, so it's mask is 200000FF0000000000
Sub-band 7 uses channels 48-55, and channel 70, so it's mask is 4000FF000000000000
Sub-band 8 uses channels 56-63, and channel 71, so it's mask is 80FF00000000000000
To select all channels, you'd use FFFFFFFFFFFFFFFFFF
The configuration app default is blank, which results in the selected region's default channels being used. In both the US and ANZ region, this is the same as enabling all channels, and will lead to packet loss if your network is only using a single sub-band.
Min / Max Data Rate:
These parameters select the minimum and maximum data rates to transmit at, when ADR is not active. A '0' selects DR0, the lowest data rate with the longest range. If you set both parameters to the same value, the Guppy will always use that rate. If you choose a range, the Guppy will alternate between the allowed data rates in such a way as to spread the transmit time evenly. This means it will use the higher data rates more often. Using a range of data rates allows the network to support more devices per gateway, but reduces your guaranteed range to the range of the highest data rate. Using higher data rates may allow you to send more messages per day. Please see the section 'How The Guppy Uses LoRaWAN Airtime' above. The default is DR0-DR2.
Adaptive Data Rate:
By default, the Guppy does not request ADR when sending uplinks, choosing instead to control its data rate according to the configured range. However, you may wish to enable ADR when the tracked asset is mostly stationary, to optimize power usage and network capacity. You can also force ADR on at all times, in order to control it using a policy on the network server.
If the Guppy is configured to enable ADR when out-of-trip, it will switch to its lowest configured data rate, and highest transmit power, whenever a trip ends. Thereafter, the network server will configure it to a lower power mode if appropriate.
Please remember that the ADR adaptation rate in LoRaWAN 1.0 is extremely slow. If the device loses connectivity, it takes 96 lost transmissions before it will attempt to increase its transmit range. This adaptation rate will be adjustable in a future LoRaWAN release.
By default, the Guppy rejoins the network once a week, in case the network server has somehow forgotten the session keys. This period can be extended to up to 255 days, or disabled entirely (0). However, if a device is accidentally deleted on the network server, or the network server suffers a database failure and loses the session keys, the server will be unable to decrypt any device data until it has rejoined. Rejoining weekly generates several extra transmissions, but lowers the time spent out of service in the event of an accident. The rejoin is exactly equivalent to a device reset, and takes place even if Activation is set to ABP.
Heartbeat Tx (0-7620 mins):
The maximum time between status updates. Setting to 24x60 = 1440 mins results in at least one status update per day. If movement causes additional updates, the next heartbeat update is scheduled for 24 hours after the last movement update. The default is 24 hours.
In Trip Tx (0-7620 s):
The time between status updates when in-trip. Set to zero to disable these updates entirely. Note that in Europe, radio regulations will prevent the effective time between transmissions from dropping lower than about 115 seconds when using the lowest data rate. The default is 10 minutes.
+ After Hours:
The time between status updates when in-trip, and after-hours. This allows you to specify different detail levels outside of normal working hours. You can use it to save battery by not tracking non-business trips, or to provide detailed tracking in the event of theft. Set to zero to disable in-trip transmissions when after-hours. The default is 10 minutes.
Trip End Timeout (0-2550 s):
The time required before a trip ends, if no movement is detected. Set to zero to disable trip tracking entirely, which saves a small amount of power by disabling the accelerometer. You will still get heartbeat transmissions with the trip tracking disabled. The default is 5 minutes.
Tx On Start:
When set, a status update is scheduled at the start of a trip. This is often unnecessary, since the start position is generally already known from the end of the previous trip. The default is true.
+ After Hours:
When set, a status update is scheduled at the start of a trip when the trip is after-hours. You can use this to implement theft alerting. The default is true.
Tx On End:
When set, a status update is scheduled at the end of a trip. This lets you know where the asset is, with one caveat - if the destination is underground parking, it may have no coverage. The default is true.
+ After Hours:
When set, a status update is scheduled at the end of a trip when the trip is after-hours. The default is true.
Man Down Timeout:
The Man Down indicator is a bit in the Guppy's uplink which shows if the device has stopped moving for a configurable time. This can be used to detect if an asset has been idle for a few weeks, a car has been stopped for a few hours, or if livestock have died. The timeout can be set from 10 minutes to 21h10m, in 10 minute increments, or from 1 day to 63 days 12 hours, in 12 hour increments. A value of 0 disables Man Down indication, saving a minuscule amount of battery life (< 1%). The default is disabled.
+ Fix On Set:
This chooses what action to take when the Man Down indicator bit becomes set. You can choose one of:
- Do nothing - the bit will upload when the next heartbeat is sent (default)
- Transmit once, assuming the network connection is ready (join has been successful)
- Keep retrying (with backoff) until the network connection is ready, then transmit once
The current firmware only supports unconfirmed uplinks, even when retrying.
+ Fix On Clear:
This chooses what action to take when the Man Down indicator bit becomes clear, and is configured as above.
By default the Guppy will send a statistics message every 3 days. The statistics help keep track of battery usage, and diagnose vibration issues. However, you may wish to disable the statistics to minimize transmissions.
Enable Tilt / Triggers:
This enables reporting of the Guppy's current tilt angles, and arms any tilt triggers configured below. Enabling tilt support has battery implications for two reasons:
- When either tilt or Man Down are enabled, the Guppy must send additional bytes in its status uplink, which uses up to 15% more battery in certain configurations. Whether it uses more power or not depends on the exact Spreading Factor in use.
- The Guppy also spends a minuscule amount of energy sampling the tilt angles, and monitoring for any enabled triggers. Under normal circumstances this doesn't amount to much, but if the Guppy is constantly moving it can add up to 60% of the battery per year. So if constant movement forces you to completely disable the trip tracking to save power, you should also be sure not to configure any tilt triggers (but you may leave tilt reporting enabled).
Tilt is disabled by default.
Trigger Axis / Angle / Type / Min / Max/ Hysteresis:
The Guppy allows you to configure up to 3 tilt triggers, which will fire off a transmission whenever the tilt angle passes a threshold. The tilt angle specified in the trigger is the angle of the direction of 'down', relative to the Guppy. There are several different references to choose from, and two types of trigger - a range trigger, and a delta trigger.
- Axis chooses one of the device axes to measure against. When the Guppy reports its current tilt, it reports it relative to the Y axis, so this is the natural choice when your mounting options are flexible.
- Angle chooses whether to measure the angle between the chosen axis and 'down' (called the inclination), or the angle around the chosen axis, according to the right-hand grip rule (the azimuth). Inclination angles range from 0 to 180 degrees, while azimuthal angles range from 0 to 358.5 degrees, wrapping at 360.
- Type chooses between a range trigger, and a delta trigger. A Delta trigger goes off if the angle changes by more than the Min angle, since it was last reported. A range trigger goes off if the angle leaves the range defined by Min, Max, and Hysteresis. The Hysteresis is added to or subtracted from the range boundaries, to prevent chattering of the trigger when the angle is close to the threshold.
For diagrams of the trigger angles, see below. The default configuration for all triggers is disabled.
Retry Trigger Tx:
When a tilt trigger is set off, it triggers a single unconfirmed uplink, if the network is ready (join has been successful). Enabling retries will retry the uplink (with backoff) until the network connection is ready, then transmit once.
This is the timezone used for after-hours calculations. The default is UTC.
This is the amount of time that the clock shifts during daylight savings time, if applicable. It applies only to the after-hours calculations, and will usually be one hour, or zero to disable daylight savings. The default is disabled.
+ Start / End Nth / Day / Month / Time:
These parameters allow you to specify the start and end times of daylight savings, if DST Shift is nonzero. They only apply to the after-hours calculations.
Most countries use a relative specification such as 'The 1st Sunday of April, at 02:00 local time', or 'The Friday before the last Sunday of October, at 2:00 local time'.
For the first example you would choose '1st', 'Sunday', 'April', '2:00'. For the second, you'd choose 'Last', 'Sunday', 'October', '-2d 02:00'.
You can also choose a fixed date and time using for instance 'Absolute Day', 'Day 28', 'April', '02:00'.
The time is always in the current local time zone, including any daylight savings adjustment.
Mon / Tue / ... After Hour Start / End:
These parameters allow you to specify which times are after-hours, for the purpose of applying different trip tracking parameters at those times.
Set both the start and end parameters to 00:00 to disable (default).
Set the start to 00:00, and the end to 24:00, to make the entire day after-hours.
Setting a start time to before the end time makes the intervening times after-hours.
Setting the start time to after the end time makes the times between 00:00 and the end time, and between the start time and 24:00, after-hours.
Wakeup Threshold (1-8):
This sets the amount of force, in units of 63 mG, that will wake the accelerometer up. Setting it too high might result in trips being missed. Increase this value if you have a problem with small vibrations setting off spurious trips. The default is 2 (126 mG).
Wakeup Count (0-12):
This is the required time duration, in units of 80 ms, of the force that will wake the accelerometer up. Increasing this value will make the accelerometer less sensitive to short, sharp forces, but increases the chances of a trip start being missed. The default is 1 (80 ms).
Disable Wake Filter:
Set to disable the trip-start filtering, that is usually applied in addition to the Wakeup Threshold and Wakeup Count. The wake filter rejects small disturbances, requiring sustained jostling before a trip starts. This is good for battery life, but if you require higher sensitivity, or the filtering is causing too much latency for your application, you can disable it. The filter only starts a trip when it has seen 1 seconds worth of above-threshold movement in a 4 second period, or repeated short movements over several 4 second periods. This setting disables the filter during work hours only. The default is false (not disabled).
+ After Hours:
Set to disable the trip-start filtering after-hours. This can be useful for theft alerting, as it allows you to detect even minor bumps after-hours, without producing many false positives during normal work hours. The default is false (not disabled).
How The Guppy Expresses Angles
The Guppy's uplink and triggers express angles in terms of the direction of 'down', in the Guppy's spherical coordinate system. The diagram below shows how the inclination and azimuth in the Guppy's status uplink (uplink 1) are calculated. In the diagram, the Guppy is standing upright, with the battery compartment and screws facing away from the viewer. As it is rotated, you can read off the angles from the arrow.
While the status uplink expresses the azimuth and inclination relative to the Y axis, the triggers may be defined relative to any axis. The diagram below shows how to take the measurements relative to the X axis instead of the Y axis:
Similarly, the azimuth relative to the Z axis would be measured counter-clockwise from the X axis, in the XY plane. If you stick out the thumb of your right hand in the direction of your chosen axis, your fingers will curl in the direction of the corresponding azimuth.