Introduction: IR Wireless Temperature Sensor With ATtiny85
Arduino is simple and very powerfull open source/hardware platform where only your imagination can stop you.A few days ago I read an instructable that inspire me to do my own.The instructable is about how you can send strings of data from one arduino to another.Everything is ok but I wanted to make it with Attiny85 .but unfortunately libraries are not supported with this microcontroller.So, I need to find a way how to generate 38khz and send modulated data and how to translate those data.I'm not enough pro :) to know how attiny85 to generate 38khz itself so I used old good one 555 timer.Everything is good but now I must to send data somehow.There are 3 possibilities:
1-By controling reset pin of the 555 timer
2-switching on/off power supply of 555 timer
3-switching on/off LEDs(timer is always on)
I used 3th variant.
Step 1: Parts List
Microcontrollers and timers:
1xATtiny85(you can use any microntroller from Attiny family)
Resistors and trimers/pots:
Any pnp/npn transistors.In this project I used 1xBC547(npn) and 1xBC327(pnp)
LM35DZ couse it's easy to use
LEDs and transmitters:
Any IR leds.
You can use any ir receiver.Why??Because you can tune to the right frequence 555 timer with 10k trim/pot.
*To be exactly 38khz you must to tune trimer/pot around 7.979k or just mesure frequency with multimeter
*Supply voltage can be everything between 6.8v-30v
*Attiny85 is running at 16mhz internal oscillator
Step 2: Shematic and Pinouts
Step 3: Transmitter Code
After you finished with circuit you must to upload some code..right? :D
In my project I used morse alphabet to send data.
There are two files, first one is little modified Morse library and the second file is main program.
I uploaded the code trought Arduino with tiny cores.
You can find it here:
Step 4: Receiver Code
It can be done a lot of optimizations.Because now you can only send numbers(in my case temperature).
Step 5: Update
Couple pictures how I integrated this circuit.
Step 6: Final Product
Single chip solution, less power consuption
Please comment and share your ideas for improving this device.
Thanks for reading!
btw: English is not my native language so sorry for mistakes and etc.