I have been using TTGO LoRa32 V1 development boards for my soil moisture meter project based on a LoRa wireless data link, and posted images of them on 15 February and 16 March. I discovered that V2.1 boards are available. So I bought one for about $23 to compare.
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| TTGO LoRa board v2.1 - note the 16GB SD card |
The LoRa chip is unchanged; still the same SX127x family ( newer chips do exist ), but now in a metal can. The screening could give it improved rejection of interference which can cause false data packets to be generated. I have solved this problem anyway in software by including a destination address in the packet header.
The antenna connects directly with a SMA connector on the board, so not requiring the use of the coax cable pigtail of V1 with its inherent signal attenuation. I am noticing at least a 10dB ( x10 ) improvement in received signal level with V2.1 when I use both V1 and V2.1 boards side by side.
V2.1 has a micro SD card slot. While not very useful for my moisture meter which is connected to on-line services for data storage, it was fun to try out and does mean that I could save all soil moisture measurements even if I am not running my Node-RED server. I bought a 16GB card ( the smallest I could find ) which is enough capacity for the next 112 thousand years of soil moisture measurements !
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| Measurement & time-stamp saved every hour to file moisture.txt on SD card |
The image above highlights two interesting features of the soil moisture meter. At the time it had been in continuous operation for 719 hours, and at night.
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