this is an rf receiver prefilter for pilight build with an ATTiny45 / 85. it prefilters the received signal to reduce the load for pilight (http://www.pilight.org). you be warned: this could potentionally damage your raspberry pi and also other hardware. i take no responsability for any damages! use at your own risk!
- Install avrgcc:
sudo apt-get install gcc-avr avr-libc
- Install modified avrdude:
wget http://project-downloads.drogon.net/files/avrdude_5.10-4_armhf.deb
wget http://project-downloads.drogon.net/files/avrdude-doc_5.10-4_all.deb
sudo dpkg -i avrdude_5.10-4_armhf.deb
sudo dpkg -i avrdude-doc_5.10-4_all.deb
- Calculate the MIN_PULSELENGTH and MAX_PULSELENGTH values
MIN_PULSELENGTH = ( shortest expected pulse - 10% ) / 10
MAX_PULSELENGTH = ( longest expected pulse + 10% ) / 10
the shortest expected pulse is the minimal base pulse-width of all your protocols
the longest expected pulse is the maximal base pulse-width of all your protocols multiplied by 34
- Compile and program ATTiny:
make all
###Calculate fuses: http://www.engbedded.com/fusecalc/
###Pinout:
I use this circuit without resistors. if you want you can even power the ATTiny with 3.3V, it works for 4 out 5 ATTiny's, but i think the timing is less accurate.
| Name | Raspberry Pi V2 | ATTiny45 | 433 Receiver |
|---|---|---|---|
| MOSI | 19 | 5 | - |
| MISO | 21 | 6 | - |
| SCK | 23 | 7 | - |
| RESET | 24 | 1 | - |
| PI_IN | see pilight cfg | 2 | - |
| REC_OUT | - | 3 | DATA_OUT |
to change the pins create an .avrduderc file in your home directory containing (the numbering is wiringpi numbering!):
programmer
id = "gpio";
desc = "Use sysfs interface to bitbang GPIO lines";
type = gpio;
reset = 8;
sck = 11;
mosi = 10;
miso = 9;
;
###ATTiny85
If you want to program an ATTiny85 add a parameter when calling make:
Make all type=t85