So my final project has been hitting some major pitfalls the past couple days. First, there is no clear documentation about connecting the ATtiny84 and RFM69 packet radio. I need to do this with the MOSI, MISO, SCK, SS, and an additional S->M interrupt. I believe I had found all the correct pins for the connections on the ATtiny84 yet it still was not working. That was using the LowPowerLabs RMF69 library. I then found this branch of the same library which explicitly says it supports the ATtiny84 yet it wouldn’t compile. The error thrown was that the SPI interrupt pin wasn’t defined for the ATtiny84. I went into the library’s header file and defined it explicitly and then got another error saying the SPCR and SPSR are not defined. Now these correspond to configuration registers that need to be set in the ATtiny84 microcontroller and that is not something I think I would be able to accurately explicitly define…
At this point I believe I am officially going to pivot my idea. I am going to instead make a PCB with red LEDs in the shape of a heart and connect it to the ESP8266 which will be subscribed to the adafruit MQTT broker. When I send a text message that says “love” the heart will begin blinking as if it is beating. It is designed for people to remind their loved ones that they are thinking of them even when they can’t pick up the phone and call.