Keith | Dec. 16, 2019

Works Perfectly

For Grasshopper LoRa/LoRaWAN Development Board

I purchased two Grasshopper boards to prototype a LoRaWAN product I am working on using MachineQ gateways.

The build quality is excellent, and the boards arrived quickly and well-packaged. I used the example software to connect to MachineQ without any issues. The Prototype is going to require some modifications, so having the schematic and board layout available is very helpful. The complete LoRaWAN library is taking up about a third of the flash and about a quarter of the dynamic memory in the STM32L0, so there is plenty of room for my code.

I'm using an in-door MachineQ gateway, and getting a range of at least a half-mile through other buildings and into my car. This is really good range, especially for a broadband chip-and-trace antenna. The micro-fl connector will allow me to add a better antenna for better range, but I have not tried this yet because I really don't need it. A half-mile in an urban environment is great.

I had a couple of questions, and Kris (onehorse) answered them quickly and courteously.

If you need a small, pretty much bullet-proof, and well-documented LoRaWAN solution, this is it.

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Response from Tlera Corp | Dec. 16, 2019

Thanks for the nice review Keith!

Glad to know the one-size-fits-all chip antenna is working so well. I have never done any kind of serious range testing but anecdotal reports such as this make me believe the useful range for most applications would be in the hundreds of meters.

Karl | Oct. 31, 2019

Great Development Board

For Grasshopper LoRa/LoRaWAN Development Board

The documentation was somewhat difficult to go through, but we were able to get the functionality we needed to work. I had an issue with the module not being picked up over usb, but I got a quick response how to solve that. Just exit Arduino, plug in the kit to usb, hold the boot button, then press the reset button. Overall, the examples were great and this module was a really great way to jump right into LoRaWAN for an absolute beginner like me. The LoRaWAN_Callbacks sketch has an example a of downlink for those that may have spent a few minutes longer than they should have trying to find that example.

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Response from Tlera Corp | Oct. 31, 2019

Glad you were able to make this work for you. Our goal is to make the Grasshopper development board easy to use but I agree we could do better on the documentation. Still, we hope programming via USB using the Arduino IDE outweighs whatever documentation deficiencies remain. The CMWX1ZZABZ-078 module is quite capable and the examples are there to help you get started. Just let us know if you have any trouble by sensing e-mail to tleracorp@gmail.com.

Christopher | Oct. 14, 2019

Stefan | Oct. 14, 2019

Works fine but but has some caveats

For SDIO Card Reader for Dragonfly

I purchased the SDIO card because it is the only 4 bit solution for STM32L4 (apart from the ST eval board) and has short data lines and easy access for a logic analyzer. I was not interested in the Arduino stuff although I looked into the arduino core code out of interest.
Positive:
-short data lines to SD-card which enables the use of high clock frequencies.
-decoupling caps on board
-Arduino core code has been programmed natively on the sdmmc register interface so no ST HAL. Very impressive and I suppose a lot of time was spent on this.

Possible improvements:
-mounting on the Dragonfly. To avoid covering the RGB-LED it has to be mounted on the bottom, but in this case access to the sd card is really cumbersome
-no pull-ups on CMD and data lines. You have to rely on setting the internal STM32 pull-ups
-D3 is connected the blue part of the RGB LED and the is no solder bridge. This imho is a poor choice signal integrity wise and power consumption wise

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Response from Tlera Corp | Oct. 14, 2019

Thanks for the detailed review Stefan!

This is a small board with a fair number of peripherals so some trade-offs had to be made in the design. We agree having the rgb led share other pin functions is undesirable, but it is the choice we made. As far as power usage, SD cards are high-power devices, which is one reason the SD Card Reader interface design for the Dragonfly seems somewhat of an after thought; it was! Nevertheless, we have found that it can work well despite the awkward access to the SD card itself.

Amir | Aug. 14, 2019