Few months ago, I published my first DIY digital thermometer. However, like any simple projects/prototypes, that project needs some improvements. Previously, I used a voltage regulator that has a 100mA rating. Though it was able to source current to the whole circuit, it gets too hot easily. Another problem with that was that the voltage regulator was very close to the sensor. Since the voltage regulator heated up easily, it always affected the temperature reading of the digital thermometer.
To solve those problems, I came up with a second version of digital thermometer.
This version of digital thermomter is basically the same as the previous one. However, this version of digital thermometer solves the problems encountered previously. There is also some improvements in the aesthetics aspect and also in the firmware.
I used a voltage regulator with a higher current rating. This is to avoid the regulator to heat up easily and to dissipate any heat as fast as possible. I also put the voltage regulator as far from the sensor as possible.
I also used a smaller and better seven-segment display. This has resulted to a smaller but more beautiful board. It also resulted to easier PCB routing.
However, I kept LM35 as the sensor. I had no reason to change the sensor at all. Besides, this temperature sensor is probably the easiest to use.
To keep the functionality simple and the same, I did not replace the microcontroller that I used in the first version. I kept ATtiny26 as the brain of the digital thermometer. It is easy to use and just enough to my application.
Build it…
If you are interested to build this project, here are the source files for you:
good day sir., can I use any 4 digit &-segment display in this project?
Not always. I saw some 4-digit 7-segment displays with different footprints. However, you are always open to modify the schematic and PCB to suit your needs.
I see, can you send me an email sir about the data sheet of that 7-segment. Thanks in advance
I’ll post the link of the datasheet. I’ll also send it to your e-mail. Thanks.
http://www.sparkfun.com/datasheets/Components/LED/7-Segment/YSD-439AK2B-35.pdf
Will be much convenient for every one, if you put schematic and other details in single PDF document. Like most of others, I dont have schematic designing software to view your schematic and PCB details. However thanks for excellent enhanced project.
Thanks. I’ll consider your suggestion in the future. I’ll upload the pdf files later
is this doable with this
https://www1.elfa.se/data1/wwwroot/assets/datasheets/neCA56-12YWA.pdf
Im a noob at these things and Id love to do this but how do I need to modify the schematic to make it work?
Could you show me?
All I know it needs common athode.
Thank you very much.
Really nice job with the thermometer. it looks very clean, which i respect. i’m really interested in building one for my car, i could really use the help from that pdf document you promised. good luck with everything!
Sir i want to to a similar project using ATmega 168, MCP9700, and 4-digit seven segment display. Will i have to make so many variations in my project? Am a newbie and i wish to use your tutorial. thanks in advance.