Using SAMD51/Wio Terminal

A follow up – I had this running for about 6 weeks last year.

The code is in my fork is at  https://github.com/neilh10/ModularSensors/tree/release1/examples/samd_log_display_mmw  and is available to the main at any time.

For test purposes, I positioned the temperature sensors in my office, attached to different areas round the heating vent, with the winter heating kicking in.

This is is very much an alpha test – its designed to do an end-2-end system test and characterize areas that need more work.

What showed up was the difficulty in labeling or easily “tracking” what was being measured . It turns out there isn’t the capability to give multiple sensors of the same type (DS18 thermistor) a “nickname” to describe the location that they are positioned in

I documented it here https://github.com/ODM2/ODM2DataSharingPortal/issues/686

For the DS18 temperature sensor readings to be easier to decode and track – the Arduino world of make it easy – I would want to add distinguishing labels – hints to understand the graphs –  “Vent Output”, “Vent Underneath”, “Vent-Horiz 1ft”,  “Window ledge”

Of course for analysis it can be repeatedly downloaded – brought into a spreadsheet, and meaningful labels added/

Some other issues,

I wanted to configure the DS18 temperature sensor s/n in my .ini file – to make it easier to manage the sensors. However for some reason moving the DS18 from standard static initialization, to a dynamic initialization and then setting the s/n number failed to work. It should be easy – but that’s the story with software – I’m missing something somewhere. In the interests of trying out the alpha test config  I created a bug to be able to track it later and moved on

As I had discovered in testing, the Wio Terminal internal WiFi networking module RTL8720 – has some problems with hanging when dealing with external conditions. A couple of other people have the same issue, No answer from Wio Terminal about this. https://forum.seeedstudio.com/t/rpcwifi-problem-when-wifi-is-lost/262273/4

As expected from a circuit analysis the Wio Terminal, while nice looking, doesn’t do Low Power. I had wound down the clock frequency to use as little power as possible, and still the 6Ahr battery  lasted about 2.5days.

Conclusion : This has shown that the  ModularSensors modifications for SAMD51/SAME51 processors with ARM tools works. The SAMD51/SAME51 is good fit for a sensor node as it has an architecture with number of configurable serial peripherals – including  possibly up to 6 serial UARTs+I2C+SPI,  and 32DMA and 2MBytes program flash + low cost external flash that can be dual usage.  However I need to try with some other SAMD51 boards that can achieve a low power state. I have a few Adafruit options, some  with LCDs.  I also need to be able to easily interface to an LTE Modem,  and for Modbus generate +12V & RS485.

Other processors include the newish lowish power, ESP32-C6 with 3 UARTS could also be attractive, but is a different tool set. The ESP32 based “M5 Stack” boards are trying for lowpower by turning off the electronics  all together.