How to connect and multiplexing multiple lm35 sensors on arduino uno

Other Hardware Sensors
1

Hello anyone i am new here and i want to build a temp station at my house for temperature checking.
I searched the internet but i was not satisfied about the results so i want to know how to connect 5 and more lm35 sensors on the arduino board and how can i read each sensor's temp on the pc.
Thank you in advance

2

For this purpose : five or more sensors, which will be far away from the micro-controller LM35 is not a good idea.
The DS18B20and is OneWire bus is more suitable

3

Thanks for your answer.
The distance will be max 30 to 50 cm from the controller.

I want to try with that. One professor of mine proposed that http://www.omron.com/ecb/products/pdf/en-g5v2.pdf

this is an DPDT relay at 5v rating. Every 2 lm35 will connect on this relay

Is that possible to make it.

4

I'm not sure why you need a relay for this. You can read individual LM35 sensors from an Arduino's analog pins - since the Uno has six, it should suffice for your application.

5

wildbill:
I'm not sure why you need a relay for this. You can read individual LM35 sensors from an Arduino's analog pins - since the Uno has six, it should suffice for your application.

This is the way I'd go.

6

Ok understood.
Could you please tell me that. If i want to connect 8 lm35 because i need them for check more points simultaneously can i do this without the multiplexer and connect them to a relay like the omron gv5? It had to be 8 lm35 for 4 relays dpdt right? That is my idea.
Thanks a lot.

7

Most arduinos would handle that quite easily. Which model do you have/intending to get? Checkout the table on this page. You'd be interested in the number of analog inputs. Most are capable of 8.

http://arduino.cc/en/Products.Compare

8

I have the Uno

Has 6 analog inputs and 14 digital outputs

I noted that every relay i posted early needs one digital input to work.

9

It looks like you could attach four sensors to one of those relays, using two analog pins to read them.

Note though that although the Uno has six analog pins, it only has one ADC shared among them. This means that readings from one pin may impact the results of the next. If you see this, a common solution is to read each pin twice and discard the first reading.

10

Hello again.
Finally after a lot of googling around i decided to use this mux for analog signals SparkFun Analog/Digital MUX Breakout - CD74HC4067 - BOB-09056 - SparkFun Electronics

For starters i want to connect 8 lm35 sensors and add more of them in the future.
So, because i am new to this could you please help me with the code in order to connect and get this circuit to work. I only tried to start the arduino board with only one lm35 but i don't know how to do this with the multiplexer and 8 lm35.

Thanks a lot