D1 R2 WiFi ESP8266 Development Board Compatible forUNO Program By IDE
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I am delighted with this little board, it is well made and very fast. Hardware wise a very high quality product. There is one caveat if you are using this with arduino you must install downlevel Arduino 1.6.5 ide as the Wemos libraries are not yet supporting the 1.6.6 ide. If you try to use this ide your code will refuse to compile with warnings like "Warning: platform.txt from core 'WeMos LGT Boards' contains deprecated tools.avrdude.cmd.path=" Please keep in mind, the deprecated code will only stop you from developing with the latest IDE, it works very well with the last version! I feel certain that the Wemos developers will soon fix the library. Overall I think this is a valuable product for those that wish to go beyond the capabilities of a standard Arduino and considering the fact that it has built in WiFi one should conclude that this board is a bargain. See request at "http://webcache.googleusercontent.com/search?q=cache:zKBDmcwzwEsJ:https://github.com/wemos/WeMos_Boards/issues/4+&cd=1&hl=en&ct=clnk&gl=uk"
After configuring my IDE and downloading the relevant examples (takes about 15 mins to do this) I then had great success and managed to create a simple HTTP Web Server (see photo). Only restriction is one analogue input pin available so only one sensor can be connected. Perhaps I2C can get round this limitation (not yet tried). Also, all pins are 3.3v so watch out for 5v external boards which will damage this one without reducing that (easy to do with level converters or even a voltage divider with two resistors). I also connected this to a NTP (Timer Server) so no need to connect to a DS3231 RTC (Real Time Clock) module; time always up to date! Worth buying one just to experiment with and seeing what can be done once the wires are gone and you have wifi freedom.