LED Thermometer with LM35 & LM3914 - PCB Tutorial

[@niko2388]

Thank you so much bro, I had project work and I chose this thermometer and got the highest grade!!!!!!!

[@Stefano91ste]

Glad I could help!😎😎😎

[@mikewelch3903]

Stephano, I have the PCB file in my JLCPCB cart. I am going to order these circuits. But before I do, I was wondering if you could advise me about an alteration to this design? In place of the LM35, could you offer a suggestion to replace it with the KY-024 linear Hall Effect module? I’ll wait on your reply before placing my order with them. Thanks!!!

[@Stefano91ste]

Hello, No, you cannot replace LM35 with the KY-024 sensor, since the integrated LM35 is a sensor with an internal resistance that varies as the temperature changes, while the one you propose has a completely different operating principle.

[@mikewelch3903]

@@Stefano91ste, thank you for your reply. Maybe I can ask it in a different way: “What modification to this circuit would you need to do in order to use the KY 024 instead of the LM35?” If that is something that would be possible, I will go ahead and place my order JLCPCB.

[@kiranbabu2414]

Simply superb, can the temperature be displayed on led board. Instead of many led lights can a single multi coloured led be used. Thanks in advance

[@fuelknightmare]

Can you please provide a schematic and pcb file. Thanks. need these for my school.

[@Stefano91ste]

Hi, you can find the circuit diagram in the video at 0:28 and link to download the PCB in video description.

[@ahmedrayhan3625]

hi ! thanks for the video, I tried to setup this circuit using all the components you mentioned. But mine is not working for some reason. I used a 9v DC battery to power the circuit. Wherever I connect the vcc with the input of LM35, the sensor gets very hot, unbearable to touch. also the lights doesn't turn on. Is there any troubleshoot or other circuit you would recommend please.

[@Stefano91ste]

Hi, it also happened to me during a first test on breadboard.. unfortunately, due to an oversight, I had mounted the LM35 sensor in the wrong way

[@ahmedrayhan3625]

@@Stefano91ste Hi could anyone please let me know why we used 1k resistor and the 10k resistor here ?

[@Vorterix8]

Does this pcb come with coronavirus? :(

[@Stefano91ste]

Hi Vortex 8 - JLCPCB has issued a notice on its site where it says the factory has been disinfected and that coronavirus is not transmitted via objects, but only through close contact with infected people. However, until now, until February 10 it is possible to order only basic PCB (only green, maximum 10x10cm, without special processes)

[@Stefano91ste]

However, this thing about the virus scares, I live in Italy and people are starting to worry.. in your country how is it going?

[@Kostanj42]

corona virus dies after 24 hours outside so we shouldn't worry ;)

[@Stefano91ste]

Excellent news, although 24 hours can be many!

[@milosgagic4820]

@@Stefano91ste In my country, Serbia, journalist are just bombing people with scary news trying to move attention from some bigger problems we have. People even started to think if they should go to local Chinese stores.

[@gumm238]

What would I have to do, to change the increments of the temperature? For example 5 degrees? Thanks

[@Stefano91ste]

I have inserted the trimmer for small adjustments in general, otherwise it cannot be changed because LM3914 has standard values

[@gumm238]

@@Stefano91ste That's what I assumed... thank you :-)

[@HenryGhost]

how can I make something just like this but measuring only temperatures between (for example) 20 - 40 ° C ??

[@Stefano91ste]

Hi, yes it is possible, but for a job like this I would opt for a configuration with LCD and arduino display

[@whitefeatherflock5370]

U have attached a nine volt battery 🔋 na or any other to test the circuit

[@Stefano91ste]

Hi, I used a benchtop power supply, set to 5v dc

[@ahmedrayhan3625]

Hi could anyone please let me know why we used 1k resistor and the 10k resistor here ?

[@wr30025728]

Pretty nifty little project. I may have to look into acquiring one. I am a would-be electronic hobbyist. I know many things, but not enough - I am no electronic engineer. I have a very ambitious (for me) project in mind and need some help. Could you or would you (or anyone else) be willing to help? What I am seeking to do is randomly flash a field of 50 sets of 6 LEDs. I also want to make a field of 30-50 LEDs be constantly on, but randomly strobe the LEDs in each field as though they are getting a voltage spike. I don't even know if any of this is possible. I have found that maybe the 555 timer and the 4017 counter might be the ICs I need. I am not sure about caps or resistors or transistors. Timing is a challenge, too. Your help would be greatly appreciated. If this could be made on a PCB, that would be soooo cool.

[@Stefano91ste]

Hi, NE555 and CD4017 are fine, but can handle a limited number of LEDs

[@wr30025728]

@@Stefano91ste I would like to talk with you more about this. Really get into specifics. I think I am gonna be stuck with cascading 4017s. Two weeks ago, I didn't even know 4017s existed.

[@esteban19h08m]

i think you should adjust the trim to the real temperature where you have.. because you actually could have damaged the circuit by setting it to 0 celcius and should be on the real temperature you are located. So in that instance you problably remove or lowest the accuracy of the transistor specially if the soldering iron was on hot enough to melt a bit the poor transistor

[@Stefano91ste]

Hi, in the room I had about 18 degrees celsius, and the first led indicates the range 0-20 degrees - from datasheet the LM35 is designed for temperatures from -55 to +150 C Celsius, and that part of the soldering iron is not hot enough to damage it. This thermometer is designed for larger applications than the measurement of the ambient temperature, for example you could use it to measure the temperature of the boiler pipes, measure the temperature of the water, or oil, of an engine, etc... :)

[@esteban19h08m]

@@Stefano91ste i dont believe you, you even did not compare it with a conventional termometer of mercury or any other technological tecnic.

[@HanshaniLavanya1]

It's not a transistor btw

[@tonyd1149]

Dear sir, can one cascade two or more of these drivers to achieve more steps for a reduced rate of temps (0- 50C/32~120F) (for higher resolution), please? (w/more LED steps). (The idea is for a thermometer-like board, for use, in 120F to ~25F environment). Please don't spend too much of your time answering kindly. Just wondering if it's possible. Thank you. (Your results with the work displayed it awesome). 🙂

[@Stefano91ste]

Hi, no this thermometer is finished like this, I didn't think of making it expandable at the moment

[@tonyd1149]

@@Stefano91ste Thank you for the kindness of a reply. Nice work you do. Thanks again. God[Bible] Bless you. (Molte grazie).

[@Gigicdtvjvuc]

Is its ok to use a 50k trimer?

[@Stefano91ste]

Yes you can

[@Gigicdtvjvuc]

@@Stefano91ste thanks, and is it ok to not using the 18k resistor if the mode was connected

[@LC-ue6mp]

Thank you sir for your videos. They help me learn and make me happy.

[@Stefano91ste]

Thank you :)

[@milosgagic4820]

Very clear explanation! Thanks!

[@Stefano91ste]

Thank you :)

[@احمدابراهيم-ق4ف2ن]

please, I would really appreciate it if you can send me the proteus pcb lay out of the project, love your video its very useful.

[@Stefano91ste]

Hi, in the video description you can find the gerber files forf the PCB

[@sokauo]

Can you make a tutorial on how you create your pcbs??

[@Stefano91ste]

Hi, I have been planning to make such a video for a long time, however I will! I can tell you that I currently use Sprint Layout 6 as software for PCB

[@sokauo]

@@Stefano91ste ok cool thank you.

[@Bularistan4o]

Whats the purpose of the 18k R?

[@Stefano91ste]

Hi, its purpose is to prevent tht the first LED staying slightly ON even when it shouldn't

[@eberhardbohrer6230]

Get es auch nicht LM 335 auch oder nur mit dem LM35

[@АлександърКолчев-х7п]

is it possible to measure below zero also? like -20

[@Stefano91ste]

Yes, but the circuit must be redesigned

[@antonioagostinelli9430]

Hi! Nice project! Is it possible to have an estimation of the overall current consumption? What voltage are you supplying the circuit at?

[@Stefano91ste]

Hi, the circuit works at 9V DC and has a current consumption of about 0.05 A

[@antonioagostinelli9430]

Thanks!

[@electronic7979]

Very good

[@Stefano91ste]

Thank you!=)

[@itcprojects]

like to see one that is for Hot and Cold Thermometer if possible ?

[@Stefano91ste]

Hi, for this purpose I would have to make one with a microcontroller, unfortunately LM3914 is very limited in this.

[@itcprojects]

@@Stefano91ste could a Head Probe stick be adapted to this .?

[@Stefano91ste]

It depends on which probe you use, this thermometer as a probe has an LM35, which varies the output voltage as the temperature varies, from here it manages to drive LM3914

[@cuitala1445]

Se podría medir la temperatura corporal? Por ejemplo De una persona con fiebre

[@Stefano91ste]

- Hi, With the LM35 sensor it is possible, but it would be better to use a display with precise digits. - Hola, con el sensor LM35 es posible, pero sería mejor usar una pantalla con dígitos precisos.

[@cuitala1445]

Electronics Projects - Stefano91ste ah bueno es Perfecto gracias.! En tu canal tienes circuitos así usando una pantalla ? Me sería de gran ayuda ver cómo se junta una pantalla a circuitos así estoy estudiando electrónica y tendré que aprender a hacer proyectos cada vez más complejos, nuevamente gracias por tu contenido.

[@Stefano91ste]

- I only have a video demonstration of a display with arduino to measure the temperature, but nothing special.. - Solo tengo una demostración en video de una pantalla con arduino para medir la temperatura, pero nada especial.

[@keessmit4001]

Do you need software for the driver

[@Stefano91ste]

Hi, no it's just analog electronics

[@fuelknightmare]

I don't understand why is there only 3 resistor in the diagram he showed but when he create the circuit it has 4?

[@Stefano91ste]

@@fuelknightmare The fourth resistor that does not appear in the schematic is for the small red Led near the LM3914 (it's just a led to indicate that the circuit is powered, pwr led)

[@fuelknightmare]

@@Stefano91ste thanks, where do I coonnect this led? Because I'm trying to create this same diagram in expresspcb but don't know where to connect the 4th resistor and the pwr led, would appreciate if you tell me thanks in advance.

[@Stefano91ste]

@@fuelknightmare If you use my PCB there is already the predisposition, otherwise it is just a Led connected between + and GND, with a 1Kohm resistor on one of the two poles

[@carlob8766]

Awesome project!

[@tonyd1149]

Beautiful stuff. Molte grazie, Stefano. God[Bible] Bless.

[@Stefano91ste]

Thanks!

[@nikoborovec2087]

can i use LM3914N ?

[@Stefano91ste]

@@nikoborovec2087 Hi, yes is the same IC

[@nikoborovec2087]

@@Stefano91ste Okay thank you, is LM35DZ good for this because i cant find LM35?

[@nokiaapna]

hello sir this project make with K-type thermistor

[@joseluisureno444]

How to make it for Fahrenheit?

[@Stefano91ste]

Hi, the scale on the PCB should be redrawn for Fahrenheit

[@kasunkaushan827]

Is it didn't stop room temperature ?

[@Stefano91ste]

Hi, what do you mean with "it didn't stop room temperature ?"

[@kasunkaushan827]

@@Stefano91ste is it show room temperature ??

[@Stefano91ste]

Kasun Kaushan Yes, with the first LED (0 to 20 C) - there were about 17/18 degrees Celsius in the room

[@kasunkaushan827]

@@Stefano91ste thank you bro

[@Create-k9d]

Bhai iski ppt kha milage..

[@CoquiAudio]

awesome bro when you are gonna make an audio amplifier? 😊

[@Stefano91ste]

Thank you! - for the amplifier I don't know, I don't have much experience in that sector to design a serious one from scratch.. maybe some KIT =)

[@CoquiAudio]

@@Stefano91ste I have a project that is easy too build the Greenamp IPS driver audio boar plus the Arc Welder output power board OPS 5P bias adjustment is easy to do 26mV voltage drop across a emmitter resistor if you want I can send you the files and schematic and studied before you comit to it :)

[@Stefano91ste]

I know, I saw some of your videos on amps, they are very professional! If you want, it would be interesting to see them, but I think I will have to start from something simpler =)

[@didieralbertoparedeszarago2154]

Súper cool.

[@Stefano91ste]

Thank you!

[@tulussetiawan6534]

Very nice

[@Stefano91ste]

Thank you!

[@Zen-fb1pz]

i will sub you

[@rodrigomonguilhotti]

Like!!!