SenseCAP (Seeedstudio) has launched a Kickstarter campaign for launching it new LoRaWan product, a tracker based on LR1110 Semtech transceiver. This Kickstarter is a bit unusual as the product is already designed and operational. It’s more a way to have a minimum of order to initiate a production batch with a guaranteed volume.
This tracker exists in different version with different capabilities and sensors. The version I received for testing it is a T1000-A, able to get outdoor position with GNSS, indoor position with WiFi, temperature, light and accelerometer data.
The device works with a mobile application SenseCap Mate, the registration could be a bit more smooth but the design is correct. The pairing with the device is made with a QR-Code on the back of the tracker.
The configuration need to pass the tracker in configuration mode and is made over Bluetooth with the application. The configuration mode switch requires to maintain the button pushed for a couple of seconds. The application did not detected the tracker on the first try but it worked well the second time.
The configuration allows to select different networks:
- SenseCap & The Things Network
- SenseCap & Helium
These two choices may pass through the Sensecap servers. The LoRaWan configuration is preset in this case, but better deactivating ADR. In these mode, the device comes with a subscription $0,99/ month or $11.88 a year. The first 90 days are included.
- The Things Network
- Other Platform
These different choices may be a direct connection, so you don’t rely on a third party.
In all the cases, the default DevEUI, ApEUI, AppKey are the same but you can reconfigure it. To be noted that the device propose to enable ADR by default. ADR manage dynamically the device power base on previous communications. This is something to prohibit for a tracker. So better to deactivate ADR.
Once you saved the configuration, the device will be back in running mode, if you need to change the configuration, you need to go on the User menu in the app and select Device Bluetooth Configuration this menu location is not intuitive, but now, you know. It’s also the way you can update the device
Once in the application, you can change the position rate, by default 1 hour, you can go to 5 minutes. In the Advance configuration menu, you can change the way the device is positioning, by default it’s GPS only but you can switch to WiFi + GNSS to preserve energy indoor. You have different setup like GPS timeout. You can also use accelerometer or light, temperature level to trigger messages and position. To get the sensor values you also need to activate it in the configuration screen.
How does that work ?
The device is a tracker, retrieving a position on regular basis. The current firmware sound like a basic one, reporting a position on every X minutes.
The tracker is based on a LR1110 transceiver, this device is able to communicate over LoRaWan but it has also some really important features used by the tracker:
- It sniff GNSS signal
- It sniff WiFi signals
Inside T1000-A, is running a GPS so it’s not using the LR1110 feature. On one hand, it allows to use the T1000-A without having to rely on Semtech Server for translating GNSS data into GPS position. In the other hand it costs a bit more on the device and consumes more power.
The T1000-C/D uses LR1110 for positioning. In this case, GNSS signals are processed by a Semtech server to compute a location. This have a great advantage, the time to get a position is really reduced and this helps to get a better autonomy. The side effect is that the precision is lower than a standard GPS, better counting 50m-100m accuracy than 15 usual meters.
The WiFi sniffer is tracking the access point around and send the mac to the Semtech server to get a position from this. This works really well indoor where GPS can’t be received at the condition the database know your position. WiFi positioning depends on database used and also the algorithm selecting the access point (does it correctly filter cellphone access point as an example). I wrote a WiFi tracker where this has been described years ago.
The core engine of the tracker is a Nordic nRF52840, it’s a really powerful low power MCU with Bluetooth connectivity, this one is used for setup, firmware update, and beacon sniffing (or LR1110 do this, I have a doubt)
The tracker gives a position… It’s what we expect But it also has some cool features like it can ring a bell if you ask it, this needs a LoRaWan downlink communication, it is not immediate but it’s a good solution to find the device once you are close to it.
The position are retained in the device memory, up to 1000 points, so the tracking can be precise even when the tracker is out of network coverage by registering the information. These one will be later pushed once the device get the network back.It’s really bad for mapping but really good for tracking.
By double-clicking on the button, it rings, I assume it will later send a position, this is like an SOS option.
The size, the packaging, the ability to use it in many different conditions thanks to the magnetic charging system allowing a good resistance to water is really good for many industrial environment.
In the screen capture on Kickstarter, we see that every position comes with the sensor details, temperature, lights… These information will be available after you enable them in the device configuration page.
The Kickstarter campaigns also indicate the ability for the device to roam over different countries, I’m a bit more curious about this: The device can work everywhere and the included GPS for version A & B allows to detect the zone and the regional settings. The limit comes from the network: Helium with chirpstack is not anymore global but per zone and roaming requires some tricky operations and a rejoin. TTN is not global at all and needs different LoRaWan configuration, so I’m not sure how it will really work.
Cost of the device
The kickstarter campaign proposes the tracker for $29 with a public price of $39. This is really cost effective for a such device in my point of view.
I personally ordered a second device with the associated devkit and think about using it for some of my B2B applications, I’ll see but it’s promising.
Cost of service
The device comes with a service cost just under $1 a month. The reason behind is related to the communication cost on the network (Helium is not free and TTN neither out of respect of the fair use policy) and also the position calculation made by the Semtech servers from the data receives by the LR1110 chip fro version C & D, and covering the WiFi mac to position translation, a costly service.
Under the hood
Don’t do this .. don’t open it, it has been design to not be opened, it’s the way it gets a protection against the water.
What do we learn from this ? the battery inside is a LiPo – not a surprise – 700mAh is more a good surprise in regard of the device size. I measured the power consumption with OTII tool and the average sleep consumption is about 50uAh give 14.000 hours (about 18 months) of maximum autonomy.
The activation of the accelerometer have a strong impact on the power consumption (firmware should be improved in my experience), when the device is moving, the sleep consumption jump to 0.6mAh avg, reducing the maximum autonomy to 50 days.
Getting the GPS & WiFi then communicating on the network requires more power ( 857uWh – indoor with GPS repeater) This basically means, on a 700mAh@3.7V (2.59wh) the ability to send about 3000 messages. The autonomy of the tracker should be around the following one:
- 10 days with a GNSS position on every 5 minutes.
- 3 to 4 months with 1 GNSS position per hour
- 1 year with 2 GNSS positions per day
These numbers really depends on the GPS coverage quality and the algorithm used to optimize energy indoor particularly, better taking 50% error in this.
On start, it seems to stay up until it get joined to the network, I did not tested it much more, but it would be interesting to investigates the energy consumption in case of no networks around.
Here is an example of WiFi positioning followed by a LoRaWan transmission.
The power consumption is 24.3uWh in this example indicating you can have like 30 times more position with WiFi than GNSS for the same autonomy.
The antenna design is a clean PCB antenna for LoRaWan, located close to the lanyard, it will be better to not use any metal piece close to it. Other 2.4GHz antennas are SMD mounted. GNSS is type PiFa
The LiPo do not really have space to expend inside the packaging, I recommend to be careful with that device exposed to high temperature. Exposing the device inside a car in summer can be at risk, (like for most of the LiPo based devices).
The top face of the tracker you seen above is protected by a shield and contains the MCU, the transceiver and the GPS chips (shield is a bit hard to remove, I’ll work on this fater making more test, the risk to destroy the chip is a bit high). From a photo of the board coming from Seeed, we can expect the following elements:
On the back side of the tracker (see above) your have the different sensors.
I’ll use a bit more this device, but I really like it in the way it is well designed, low cost, adjustable autonomy up to long period of time.
It comes with all what you need to use it as a standalone, personal tracker but also as a tracker you can use as a fleet for B2B applications.
The price is really efficient to fit all these possibilities. Well done Sensecap / Seeed. Now I’m waiting my Kickstarter one to have another one in a good shape rather than opened and reassembled as it can 😉