This is a quick write up about getting some IoT bits hooked up and talking to each other. To start playing with IoT I went with a cheap ESP32 chip from e-bay along with a basic temperature sensor. This is a list of stuff I used:
- ESP-32S ESP32 NodeMCU Development Board 2.4GHz WIFI+Bluetooth Dual Mode (spec) (129,00 CZK)
- BME-280 (90,00 CZK)
- breadboard and jumper wires (360,00 CZK)
- soldering kit (500,00 CZK)
In terms cost, the entire lot came in at just over 1000 CZK (40 EUR) and I have cables to last many projects.
Keep in mind that the soldering iron should have a very pointy tip. One of the mistakes I made was to start soldering with a fat tip and that caused the solder to go all over the place. Once I replaced the sensor with a new one, I managed to solder it nicely. The end product looks something like this.
The trickiest part was to find which pins to map to SCL and SDA ports on the temperature sensor. As there are many boards out there it’s impossible to guess which pins you need to use. The thing to watch out for is to be sure as to which board you are using. I’ve wasted lots of time of looking at docs and videos for slightly different boards. Once I found the exact spec for my board I was able to update the source so map the pins like so:
#define I2C_SDA 23 #define I2C_SCL 22
With this mapping in place and correct baud rate setting, the Serial Monitor began showing output: