DESCRIPTION
Temperature and humidity sensor with link RF 2.4GHz, one version for internal use powered by battery, another for external with battery rechargable by solar panel..
Sensor based on carrier board for Arduino Pro mini described here
RF board: NRF24L01 + 2.4GHz Wireless RF Transceiver
Temperature sensor DS1721 -55°C à +125°C with precision 0.0625°C
Humidity sensor DHT11 20 to 80% (relative humidity) +/-5% or DHT22 for external use
The main application is a temperature and humidity sensor with Radio link, it is used in the FCALLBOX DOMOTIC SYSTEM
described here
Sommaire
BOM
Top view
| Ref |
Description |
Manufacturer / reference |
| L1 |
inductor 10uH 300mA min 1812 |
All brands |
| C6 |
Capacitor 10uF 10V 10% X5R 0603 |
All brands |
| C1,C3,C5 |
Capacitor 47uF 6V3 10% X5R 0603 |
All brands |
| IC11 |
DC/DC boost 0.8V to 3.3V |
MAX1724EZK33 |
| R2 |
Resistor 0R 5% 0603 |
All brands |
| R4 |
Resistor 4K7 5% 0603 |
All brands |
| R5,R6 |
Resistor 220KR 5% 0603 |
All brands |
C4,C7 |
Capacitor 100nF 25V X7R 10% 0603 |
All brands |
U3 |
Humidity sensor DHT11 |
DHT11 |
U2 |
Temperature sensor DS1721 |
Maxim (DALLAS Semi Conductor) |
|
Assembly
The board has dimensions 48x20mm
Download here the assembly drawing in PDF format
Cabling Sensor based on NRF24L01 without PA
Pictures
|
Arduino on carrier
Remove the 2 leds and the rebulator on the red circles to decrease the consumption
|
Modification to control RF module power
To reduce the consumption at minimum, add a PNP MMBT5401 and a 100R
|
Modification to reduce noise for RF module
Add a 10uF and 200uF 6V3 min.
|
Software
The project has to be compiled and loaded with Arduino IDE
Modify this line to adapt to sensor DHT22 or DHT11 :
#define DHTTYPE DHT22 // DHT11 DHT 22 (AM2302), AM2321
Download here the zip of the Arduino Project
