For room temperature 21*C LM35 showing,
- 23 *C while powered by CPU USB port.
- 18 *C While powered by a 7amph 12V SLA.
My controller consist of Arduino, adruino wifi shild, and ATMEGA32. ATMEGA32 is attached to the 4 redundant lm35. regulated 5V and GND Power rail are interconnected for all controller.
I want to share some of my observation:
- If I do another Analogue read on ground as the same manner That I do for data, e.g. For this observation I an using gain=3 for both data and ground, and taking the difference, the result become far better.
- When the power is only Battery and no connection with CPU/AC Main line, there is no apparent disturbance on the output.
In the given figure the room temperature are noted for around,
a. 1 Hr for Battery and
b. 45 min for USB USB power. Data are communicated over USB serial cable.