Digi XBee User Manual

API Operation Frame descriptions
XBee/XBee-PRO® S2C ZigBee® RF Module
187
AD0 = 0x0002
AD1 = 0x00CE
AD2 = 0x00EA
AD3 = 0x0052
T = 0x016A
To convert these to temperature and humidity values, the following equations should be used.
Temperature (°C) = (T / 16), for T < 2048
= - (T & 0x7FF) / 16, for T >= 2048
Vsupply = (AD2 * 5.1) / 255
Voutput = (AD3 * 5.1) / 255
Relative Humidity = ((Voutput / Vsupply) - 0.16) / (0.0062)
True Humidity = Relative Humidity / (1.0546 - (0.00216 * Temperature (°C))) Looking at the sample
data, we have:
Vsupply = (234 * 5.1 / 255) = 4.68
Voutput = (82 * 5.1 / 255) = 1.64 Temperature = (362 / 16) = 22.625°C
Relative H = (161.2903 * ((1.64/4.68) - 0.16)) = 161.2903 * (0.19043) = 30.71%
True H = (30.71 / (1.0546 - (0.00216 * 22.625))) = (30.71 / 1.00573) = 30.54%
Frame fields Offset Example
Start delimiter 0 0x7E
Length MSB 1 0x00
LSB 2 0x17
Frame type 3 0x94
64-bit source address MSB 4 0x00
5 0x13
6 0xA2
7 0x00
8 0x40
9 0x52
10 0x2B
LSB 11 0xAA
16-bit source network address MSB 12 0xDD
LSB 13 0x6C
Receive options 14 0x01
1-Wire sensors
15 0x03

Digi XBee Specifications

General

Operating Frequency	2.4 GHz
RF Data Rate	250 kbps
Model	XBee S2C
Category	Control Unit
Operating Voltage	2.1 to 3.6V DC
Operating Temperature	-40 to +85 °C
Interface	UART
Dimensions	24.38 x 27.61 x 9.14 mm