Firefly jar software

The firmware was designed to simulate the flashing and behavior of the common Eastern firefly, P. pyralis, within the limits of the hardware. Starting with one male flashing with a period of 5.9 ± 0.6 s, additional males will arrive randomly, with differing phase and period, and will fall into sync with existing males. Females may respond if all males are flashing in sync, 2.1 ± 0.2 s later. Appearance of an unsynchronized male will cause the female to stop responding. There can be 1, 2, 3, 4 or 6 (but not 5) males flashing at once (when 4 males are flashing, two new males will appear rather than one, due to limitations of the hardware). The LEDs representing the currently active males will be randomly chosen each flash. When there are 1 or 2 males, they will avoid using the same LED as the female, but with more than 2 that restriction is lifted. The end state is usually 6 males flashing and one female responding. After a randomly selected number of cycles (lasting 5-25 minutes), the system will reset with no flashing males or females, and gradually build up again. The likelihood of new males or females appearing each cycle is reset as well, changing the character of the interactions each time around. Random number generator seed is stored to use a different one each time.

The program is written for the AVR ATtiny85 microprocessor (and also works with a ATtiny45 on my prototype board). It uses the internal timers to time the flashes and control the LED brightness with hardware-based PWM (pulse width modulation). Two simpler programs are also included that can be used as building blocks for writing new behaviors for the firefly jar. The programs are compiled in avr-gcc. You will need some kind of programmer to install the firmware on the ATtiny; I use the USBtinyISP. For more information on programming AVRs, try starting with this tutorial.

Source code is available at Github or Codeberg.

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