LORA Temperature and Humidity Sensor

In this instructable you will learn to make a sensornode that sends data to a LORA server. This node will send:

• Air temperature
• Humidity sensor

You can use this instructable to make a node that you can use as a server.

Sensornode:

• AM2305
• capacitive moisture sensor
• arduino pro mini 3.3v 8mhz
• esp breakout
• rfm95
• wire for antenna and connections (I use a 0.8mm solid core wire)
• male to male jumper cables
• female to female jumper cables
• breadboard
• CP2102 usb to TTL

Tools:

• soldering iron
• side cutter
• wire stripper

For the antenna I use some leftover cable of my 2x2x0.8mm or 2x2 20awg bus cable.
On the things network you can choose your tranceiver and antenna frequency band by country.
These are the lengths per frequencie:

• 868mhz 3.25 inches or 8.2 cm (this is the one I use)
• 915mhz 3 inches or 7.8 cm
• 433mhz 3 inches or 16.5cm

• Remove the resistors of the esp shield (see R1 to R3 in the red field)
• Solder the rfm95 chip onto the esp shield.
• Solder the pinheaders onto the esp shield
• Solder the antenna onto the esp shield. Don't use without an antenna you can damage the shield.
• If the pinheaders aren't soldered onto the arduino solder these too

I know I can use the DTR to automatically reset the arduino but in my case I had errors uploading the code. Therefore I also used a manual reset in this instructable so if you have the same problem you can solve it by a manual reset.

• Wire the arduino to the CP2102 as following:
  • CP2102 txd -> Arduino pro mini rx
  • CP2102 rxd -> Arduino pro mini tx
  • CP2102 gnd -> Arduino pro mini gnd
  • CP2102 3.3 -> Arduino pro mini vcc
• Open the schetch in the arduino ide
• Select board arduino pro mini
• Select atmega 328p 3.3v 8mhz under processor
• Select your com port
• Click the upload button
• While the code is compiling at the moment you see the bautrate (see picture) press the reset button on the arduino pro mini (the cp2102 doesn't reset the board) also be sure to close your serial monitor while programming.

• Wire the arduino as in the sketch above
• Your arduino should now send data to the server node.

The AM2305 actually is a 3 wire sensor so you don't need the resistor. Just wire the sensor as in the picture above. The colours are the same. If you use the DHT22 instead you need to connect a 10k resistor between the red (5V) and yellow (data) wires.

In this instructable you have learned to make a sensor who sends data to a LORA gateway. It sends the temperature and the humidity of by example a greenhouse. This way you can monitor your environment and you can plan the planting of your vegetables using this data. Also you can use this sensor to decide when to open a window or to start a fan.