I recently received the Xsens MTi-680-DK INS/GNSS developement kit as part of the Xsens Position and Orientation Sensing GNSS/INS Dev Kit. I am really excited about this road-test as it is a high performance GNSS (Global Navigation Satellite System)/INS (Intertial Navigation System) module, unlike the cheaper, widely available hobbyist grade sensors in this category. If you are into building projects that require precise positioning and orientation information (drones/moving robots, camera stabilization gimbals, etc), this kit is a dream come true!
For this road-test, I have decided to post several blogs along the way before linking them to one final review post in the end. This way, I can record my thoughts/experiences as I move forward with my exploration/testing instead of doing one long post in the end (and perhaps forgetting some of those details).
Element14 sent the kit under Incoterms DDP (Delivered, Duty paid), which means any import duties/fees had already been taken care of by element14, and all I had to do was go down to the gate to collect the kit.
The kit arrived well-packed from Element14, with decent amount of packaging filler material inside. Even if the box had gotten damaged (it didn't!) during transit, I am very confident the Xsens box inside would have reached me without damage. Thankfully it didn't come to that
I have to say, the box for the Xsens kit is REALLY nice! Much nicer than what most development kits come in, anyway. Gives the kit the feel of a premium piece of equipment (which it is!)
When you open the box, you immediately see the star of the show, the Xsens device, and then the accessories are packed behind a cardboard cover.
Nice place to put the "getting started" message! Many other development kits come with a getting-started paper/card inside the box, but I think this is a much better way, since it will never get lost. We will get back to this link later.
To access the rest of the items, I pulled the orange tab to lift the cover and was greeted by a Calibration certificate for this particular unit.
When you see a calibration certificate like this for your particular unit (tracked by serial number) packed in the box, you KNOW each unit has had some special treatment
Not only the serial number is there, but the hardware and firmware versions are also recorded. This is can be useful for good traceability, later.
Here is everything that came with the kit laid out side by side.
- MTi-680 sensor
- Daughter board with ublox ZED-F9P RTK GNSS module preinstalled
- GPS antenna (from Tallysman Wireless, Canada)
- Ribbon cable with appropriate connectors for direct connection to the MTi-680 device (without the daughter card).
- 3 x Brass Mounting Screws (M2)
- A usb cable with micro-B connector for connecting to the daughter board.
As i mentioned earlier, overall the kit has a very premium feel to it and it seems that much thought has been put into making sure the user has a nice unboxing/getting-started experience. Even the round velcro pieces that keep the kit box closed are different (and nicer) than the usual ways employed to achieve the same.
One detail I am very happy to see is the brass mounting screws. What's the significance? Well, if you have a device with magnetometer inside, then you don't want to mount it using any commonly-used "ferrous" screws (iron, steel, etc) since they will distort and interfere with the magnetic field and give you degraded readings at best. Screws of non-ferrous materials do not cause htis issue, and hence are preferred. Having these included in the kit will save us the trouble of sourcing those later. Thanks Xsens!
The MTi-680 sensor device itself is very light. The shell of the sensor seems to be of Industrial plastic. I couldn't measure the weight on my kitchen scale due to it's low resolution. The datasheet says 8.9grams, which sounds about right.
Xsens has included a very high performance RTK GNSS receiver from ublox, which I am really happy to see. The ublox Zed-F9P is one of the highest resolution modules available from ublox in it's class and costs a few hundred dollars. More details can be found on the official ublox zed-f9p product page. I also managed to find the exact model for the included antenna from Tallysman wireless. This is from their TW8889 dual-band GNSS antenna series, which covers all the major GNSS bands (GPS, Glonass, Galileo, Beidou) and has an included Low-Noise Amplifier with 26db gain. The exact model number is 33-8889NM-12-2900, which according to the ordering guide has a waterproof SMA connector, non-magnetic base and 2.9 meters of coaxial cable. All of this tells me that Xsens did not spare any expense to deliver a product with some very high performing components. '
Another thing I immediately noticed and liked when I took out the daughter card is the nicely labeled silk-screen. The two switches (SW1, SW2) are labeled with their functions at different positions. And the given pin map for the "external connector" is quite detailed. Both of these things will save me (and other users) from having to open back the datasheets every time something needs to be done there. The "micro-BUS" connector is labeled on the under-side of the daughter board. The DB9 connectors do not have their pin configurations labeled on the silkscreen and will need looking at the datasheet. Perhaps these can be added to the silkscreen on the bottom side in the next iteration, too.
Two minor things that I noticed are as following:
1. The daugher board's bottom side was not as clean as the top. I reckon that the board was washed after the SMT process and before the through-hole soldering was done. The flux reside was not subsequently cleaned. I manged to clean it myself afterwards with some IPA and cotton. Although it's a minor cosmetic issue, it will give a bad impression of the product quality to the user.
2. One of the plastic standoffs on the corner of the daughter board fell off (or was missing). The choice of plastic as the standoff material is probably to avoid interfering with the magnetometer. However, may I suggest using nylon or brass standoffs along with nuts of the same material, instead. Those will last longer. The standoffs are important because of the through-hole pins sticking out the bottom.
Both the above are rather minor issues, but I'd recommend them as improvements in future.
That's it for this first blog post on the MTi-680-DK kit. In the next post we will see how easy it is to get started with the device. Stay tuned!