* Powerbutton

** Build

#+BEGIN_SRC sh
make client
make server
#+END_SRC

** Upload

#+BEGIN_SRC sh
make client-run
make server-run
#+END_SRC

** Console

#+BEGIN_SRC sh
make client-log
make server-log
#+END_SRC

** Configuration

The following fields in =secrets.h= have to be configured:

- CLIENT_MAC
- SERVER_MAC
- PMK
- LMK

You have to configure the real STA MAC address of *both* the client and server.
It might be odd that the AP MAC of the receiver isn't used, but that's how
ESP-NOW works. You can find the MAC address with the following code.

#+BEGIN_SRC cpp
#include <esp_wifi.h>

void printMacAddress()
{
	uint8_t mac[6];
	esp_err_t ret = esp_wifi_get_mac(WIFI_IF_STA, mac);
	if (ret == ESP_OK) {
		Serial.printf("{ %#x, %#x, %#x, %#x, %#x, %#x }\n",
		              mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);
	}
	else {
		Serial.println("Failed to read MAC address");
	}
}
#+END_SRC

PMK and LMK have to be 16 characters long and should be the same between the
client and server.

* References

- https://randomnerdtutorials.com/esp32-esp-now-encrypted-messages/