I’m rather new to TTN and until sofar I’ve only playing around with some Browan enddevices.
However, I am a retired Electronics engineer by training, with mainly a hardware-background and for that reason I am alo interested in developing end devices myself.
What is puzzling me is: a lot of information is available on using the Things Uno, however until so far I could not figure out where to buy such a device.
Please recommend.
I think these were discontinued sometime back, though a number remain in the various distribution channels for a while. Remember these were early units in the context of LoRaWAN development boards, with LoRaWAN, as defined and curated through the L-A emerging officially in 2015, with the TUNO comming to market late 2016/17 IIRC…there is a lot of info around based on these as they were a core item for many peoples dev activity and early intro to the technology for many years so lots of labs, tutorials and blog posts & write ups. It is basically an Arduino ‘Leonardo alike’ running with a Microchip RN2483(A)/2905 (EU/US) handling the LoRaWAN stack and can readily be duplicated if needed 
Or start with an Adafruit Feather M0 with RFM95 and LMIC-node for the starter firmware.
Thanks for your reply!
I recently bought a Adafruit RFM95W LoRa breakout board and I was thinking of doing something with an esp8266 but I haven’t figured it out yet, and maybe that would be the wrong approach anyhow.
To start with: do you have some description/documentation/website that might be of any help to begin with RFM95 and LMIC-node for the starter firmware?
Thanks a lot,
Jan de Maat
LMIC-node is very very well documented - you can get the secret location from Google.