Introduction: PIC16F84A Thermometer

This is simple thermometer with just few components.
The brain is PIC16F84A and sensor is DS18B20
Range of sensor is -55 to 125°C is possible if ONLY the sensor is in that area not the whole device!
The schematic and other stuf to make this thermometer you can find on my blog:

maco PIC Projects


ErickV1 (author)2017-02-01


romainhuon514 (author)2015-01-22

Hi, I'm trying to build this, but because the lack of some information regarding translation I'm not able to mount this circuit. I think my problem is from the ds18B20 to the 0.1uf capacitor and the battery... When I put 5v through the circuit, my 4x 7led display goes on, but nothing happens.... They are all on 0000... Can somebody help me please?

nightbringer75 (author)2011-03-04

is there an asm file of this with english comment?not other languages?coz i cant understand the program...

google translator works fine,shall I translate it for you?

Suraj Grewal (author)2013-06-11

I also made a handheld version of it with cr2032 cell,skipping the resistors of display to give them just enough charge.

Suraj Grewal (author)2013-01-19

I made one too just like you'r one-

macobt (author)Suraj Grewal2013-01-20

Good job suraj.

Suraj Grewal (author)macobt2013-01-20


Suraj Grewal (author)2012-10-12

What does those two arrows represent? General male contact

had a hard time figuring out russian schematic
those arrows are representing that those are connected to ic.
will upload a schematic soon
and also show pics of my version

abtrooper82 (author)2010-03-17

link on blog to HEX code does not work, please post here or provide a new link


macobt (author)abtrooper822010-03-18

 I check the link it's OK

abtrooper82 (author)macobt2010-03-20

This link does not work, can you email me the file.


macobt (author)abtrooper822010-03-20

hello again
And here is other link to download the hex code

abtrooper82 (author)macobt2010-03-20

thankyou, you are most kind

macobt (author)abtrooper822010-03-20

 If you need any  help,just email me.

dimjan (author)2010-02-19

geoper2 (author)2010-02-07

he is probably multiplexing the two led displays
the thing is that this is not an instructable mate its just a video of how your project works ... so please provide with the steps ?/

banja711 (author)2010-01-18

Where is the second LED display on schematics?

macobt (author)banja7112010-01-18

The thermometer in original schematis is with 4 segments,but I built it with 2 segments,other 2 show when thermometer is measuring below zero and other show half degree,example 26.0 or 26.5

banja711 (author)macobt2010-01-18

I understand that, but I can`t recognize second LED display on schematics... I see just one! How to wiring second?

macobt (author)banja7112010-01-18

Here is picture,I think I helped.

banja711 (author)macobt2010-01-18

Ok! I understand...  RB0-RB7 is a same for first and second number! RA0,RA1-Anode
I found DS 18B20+...Is it ok?

macobt (author)banja7112010-01-18

Yes,RA0 for first and RA1 for second number(anode)
And sensor is ok DS18B20
If you make post some pics.
Regards maco bt

alexev84 (author)2009-10-30

can i replace the thermic sensor used with a lm35 one with minimum modification?

macobt (author)alexev842009-10-30

I dont know about that, I am not profesional in programming,sorry

alexev84 (author)macobt2009-11-11

excuse my "complicated-preision" questions...i'm not very good at this...i need to ask you: are those led displays you use,common  anode or cathode ones?does it make any diference?mine's have a double common anode pins with op. voltage between 1.8-2.2V.and the second question is why did you used 15k resistor(alot of ohms) for the pic and the led use 5 volts for powering the pic...isn't that the actual op. voltage of the pic anyway?Thanxs in advance!

birdman0_o (author)alexev842009-11-09

The ds18b20 uses Dallas' one wire protocol. To use a lm35 you just need a A/D converter which most uC's have.


alexev84 (author)birdman0_o2009-11-09

uu thanks 

Dr. Pepper (author)2009-10-16


dude join my group!!!!!!

macobt (author)Zaphod Beeblebrox2009-10-17

What group??

Kiteman (author)2009-10-17

Looks good - how about posting the project over here (as an Instructable) as well as on your blog?

About This Instructable




Bio: My name is marjancho and I love electronics,makeing gadgets,hack and pranks.
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