Comments on: Guide for LM35, LM335 and LM34 Temperature Sensors with Arduino

By: Blessing

Blessing — Thu, 12 Jan 2023 23:33:59 +0000

Hi how can I use esp32 with lm35 sensor to read both negative and positive temperature values.
for example reading temperature values below zero, instead of giving me 0 degrees, when temperature is below that.

By: Mike Sims

Mike Sims — Wed, 16 Nov 2022 09:26:14 +0000

I’m a little confused concerning your calculations. For example, you have Voltage calculating by taking the PWM value from the ADC times 5000, then divide by 1024.

So if the ADC says that the value is 1024, then (1024 * 5000) / 1024 will be 5000 volts. Which if you then divide that by 10, the temperature comes out as 500 degrees C … is it possible that the code you published is not the exact same code that you used to get the values you published?

By: Julen Trapilla

Julen Trapilla — Mon, 05 Apr 2021 10:26:08 +0000

Hi there!

Great tutorial! it really helped me with my project. However I still need a little push to have it fully completed.

I’m using a LM335Z sensor to activate a DC motor when it reaches a certain temperature. The sensor gives the correct temperature readings out. And these values increase or decrease correctly following the temperature changes.

When the temperature readings go above the temperature limit I´ve previously set the DC motor turns on. But just at the same exact moment the temperature readings (voltage) increases drastically and stay constant so I could never cool down the sensor so the DC motor turns off when the temperature goes under the limit temperature I´ve mentioned before.

I’m struggling with this issue and can’t really figure out what’s going on.
I am a beginner using ARDUINO and I’d really appreciate some help.

Thanks a lot!
Julen

By: Sara Santos

Sara Santos — Thu, 25 Mar 2021 15:04:49 +0000

In reply to Pedro Perez.

Hi.
Yes, you are right. It corresponds to GPIO 36. So, it can read analog values.
Bur, try another GPIO, for example GPIO 32.
Regards,
Sara

By: Pedro Perez

Pedro Perez — Thu, 25 Mar 2021 14:29:47 +0000

In reply to Sara Santos. I am using ESP32 DEVKIT V1 DOIT board, so I thought that VP pin could read analog reading. Where do you suggest to connect it? Thanks

By: Sara Santos

Sara Santos — Thu, 25 Mar 2021 11:46:15 +0000

In reply to Pedro Perez.

Hi Pedro.
Why are you connecting the sensor to the VP pin?
Connect it to a GPIO pin that supports analog reading.
See the pinout for the ESP32: https://randomnerdtutorials.com/esp32-pinout-reference-gpios/
Regards,
Sara

By: Pedro Perez

Pedro Perez — Wed, 24 Mar 2021 16:53:37 +0000

Hi, First thanks for this good tutorial I am trying the code but I get a very high temperature, not sure why. I am using ESP32 board and my connections look like this:cloud.elalemanyo.de/tmp/Bildschirmfoto%202021-03-24%20um%2017.50.00-w2xMiwdjlx.png The code is the same as the one used here. But I am getting this output: Temperature(ºC): 45.66 Voltage(mV): 456.56 Temperature(ºC): 45.66 Voltage(mV): 456.56 Temperature(ºC): 45.66 Voltage(mV): 456.56 Temperature(ºC): 45.66 Voltage(mV): 456.56 Temperature(ºC): 45.66 Voltage(mV): 456.56 I am living in Germany so no way is this correct I am doing something wrong? I use LM35 DZ Thanks

By: JOSE GUSTAVO ABREU MURTA

JOSE GUSTAVO ABREU MURTA — Fri, 20 Dec 2019 13:04:43 +0000

Great Tutorial! Thanks a lot.
For best results, I recommend measuring the AREF pin on Arduino with voltmeter. And change the value on 5000.
voltageOut = (sensorValue * 5000) / 1024
For example AREF = 4.87V
voltageOut = (sensorValue * 4870) / 1024

By: Sara Santos

Sara Santos — Mon, 22 Jul 2019 11:04:01 +0000

In reply to Christopher Leech.

Hi Chris.
Yes, that’s right.
Sometimes parts from China take a long time to get to its destination. But, they are also very cheap. So, we have to wait.
Regards,
Sara

By: Christopher Leech

Christopher Leech — Sun, 21 Jul 2019 20:01:50 +0000

Much appreciated !
I am still waiting on the LM35DZ amongst other items
This can be a real show stopper as some shipments get lost and or take as long as 90 days to arrive.