While the challenge started a while back and some competitors have been able to race forward, I’ve been patiently awaiting the arrival of the kit before pressing much further. In the meantime, I’ve also been obtaining other parts which may be useful or necessary in-parallel, while juggling plenty of other commitments. Let’s take a look at what was provided.
Table of Contents
Unboxing
The kit arrived at my doorstep on Wednesday 22nd February 2023 and was a relatively small and light box. I suppose this was not unexpected as there are just two boards inside.
The box was packed with bubble-wrap to keep everything safe and sound.
Two genuine Arduino products in their boxes.
The MKR WAN 1310 uses an Atmel SAMD21 containing 256kB flash and 32kB RAM, clocked at 48MHz. This board has an onboard LoRa module from Murata and is a 3.3V-based board with the MKR form factor.
As with all official Arduino boards, it is Made in Italy and carries an authentication hologram.
Inside, the board is packed inside an anti-static foam. There is a label sheet and a thank-you leaflet.
The board itself with the MKR form factor is not dissimilar in concept to the Adafruit Feather but is incompatible. It has a set of pass-through headers offering connectivity, onboard battery charging and battery management for a lithium-polymer cell and a Quic I2C header. The microUSB-B port provides programming and charging connectivity.
Everything of importance is mounted on the top-side of the board, with the bottom containing helpful silkscreen.
Customised pin headers label the pin functions on the sides for additional convenience.
A closer look at the board shows the BQ24195 battery management IC, the Atmel ATSAMD21 microcontroller, clock crystal and the ATECC508A secure element.
This second close-up shows the Murata CMWX1ZZABZ LoRa module, a Winbond 25Q16JV1Q 16Mbit SPI NOR flash memory.
The Arduino Pro Nicla Vision comes in its own small board, with a black and green colour scheme that typifies the “pro” series of boards. It too, has a hologram for authentication and is Made in Italy.
This board is made in partnership with OpenMV.
Inside, the board is wrapped in a small anti-static bag with a leaflet and a flexible self-adhesive Molex antenna.
The board itself is more like a module, but does have a micro USB-B connection for direct connection to a computer. They’ve really packed as much as they can onto the board – having castellated pads as well as pin-header holes. The datasheet gives a comprehensive overview of the board and its components.
Components on the bottom at the top include a 6-axis IMU, a voltage level shifter and a crypto IC, but the components are not easily identified. Components towards the bottom of the rear seem concerned with power and battery, being ideal diodes, level shifter and a fuel gauge IC.
The other side of the board has the camera (with protective film), the main STM32H747AII6 Dual ARM Cortex M7/M4 microcontroller clocked at 480MHz/240MHz with 2MB Flash and 1MB RAM, an SMSC USB3320C USB transciever, a Murata 1DX Wi-Fi/Bluetooth module, a 25QL128A 16MiB SPI flash and a NXP MC34PF1550 PMIC. Two small MEMS oscillators provide clock references.
In the corner, and easily missed, are the PDM microphone and infrared time-of-flight distance sensor (ST VL53L1CB FlightSense). The latter is covered by protective tape that must be removed prior to use.
The Nicla Vision board is a lot more complex and densely packed than I could imagine. I’m surprised they were able to pack so many things onto such a tiny board!
Batteries not included!
Looking at the two boards, the MKR WAN 1310 is the logical starting point. Unfortunately, having the board on its own is not enough to get started. Hardware wise, a USB-A to USB-microB cable is needed to power and program the board, a breadboard would be good to prototype with, a compatible lithium-polymer battery would be needed if the board is expected to run without USB connection and most-crucially, an antenna is required.
I suspect the latter requirement is something not everyone can rummage around their junk box and solve easily. The board has an IPEX MHF I/u.FL connector which is similar to the ones you might find on laptop Wireless LAN cards and needs to be connected to an antenna that supports the bands you intend to use. For LoRa/LoRaWAN, this may mean EU868, US915, AU915, AS923 etc. Thus an antenna that covers the 900MHz ISM band is most desirable.
The best way is to use a pigtail that converts the MHF/u.FL to SMA (or in some cases RP-SMA) and then screw on a full-size SMA/RP-SMA whip antenna for the best range and flexibility.
Another option, especially for those who have a Molex Antenna Kit handy is to use some of the flexible multi-band printed self-adhesive antennas. There is a specific antenna that matches the band (105262), as well as multi-band cellular antennas (105263, 146185) which seem to have adequate coverage of the frequencies used.
Without this part, it would not really be possible to use the LoRaWAN radio module as there is no onboard antenna. This is somewhat understandable – antennas for such a low frequency are physically large to be efficient, and the MKR form factor is quite small by comparison. However, should people get desperate, my advice would be to remove the SMD resistor that connects the antenna trace to the MHF connector and solder down a quarter-wavelength piece of wire (8.1cm) as an antenna. This may not be optimal, but it will let you get on the air quickly. Assuming you don’t destroy the pads, you can undo the modification by soldering in the SMD resistor again.
Similarly, the Arduino Pro Nicla Vision board requires a similar USB cable for connectivity and seems to have a very specific slim battery connection which I’ve not previously used. It does have an MHF/u.FL connector for an antenna, but they’ve been nice enough to include a Molex 206994 self-adhesive 2.4/5GHz flexible antenna.
Conclusion
At last, the kit has arrived and it’s time to get started. I’ll be tackling getting the MKR WAN 1310 up and running on LoRaWAN first, before worrying about how it can be made standalone, PV-solar and battery-powered. The Nicla Vision will have to wait a bit – it’s the part I have the least experience with, so it’s probably going to take me a while to get up and running.
Thankfully, the challenge deadline has been extended – the project now ends 28th April 2023, giving us all a bit more time to get everything built. I probably won’t be winning any major prize, but the chance to get some practical experience with LoRaWAN with the MKR WAN 1310 is perhaps my main short-term goal.
[[BeeWatch Blog Index]]
- Blog 1: README.TXT
- Blog 2: Unboxing the Kit
- Blog 3: LoRa vs. LoRaWAN & Getting Started with MKR WAN 1310
- Blog 4: LoRaWAN Gateway Set-Up & MKR WAN 1310 Quirks
- Blog 5: Power, State Saving, Using Sensors & Battery
- Blog 6: Particulate Monitoring & Solar Power Input
- Blog 7: Powered by the Sun & Initial Data
- Blog 8: Getting Started with Nicla Vision
- Blog 9: Nicla Vision IR ToF & Audio Sensing, Data Dump
- Blog 10: Nicla Vision Power, Saving B’s & Dashboard Woes
- Blog 11: Summary Conclusion
