Bulletin boards

Ready to roll

After a few days (or weeks) of proofreading, three of our PCBs are ready for production : top PCB, petal PCB and processor PCB. You can find the final version of our schematics for these PCBs attached to this article.

We will need 62 petal PCB, 12 processor PCB and one top PCB for each phyllo. As we plan to make 3 Phyllos, it’s a lot of PCBs, but apart from the top PCB, they are all in two layers and quite simple. The tough part will be to connect them together and place them inside the sculpture. As explained here, Vlaya works on a 3D-printed support structure. The first draft will be printed tomorrow.

Still in discussion

We still have some minor modifications to do on the main board and the bottom PCB.

We brainstormed yesterday about the Phyllos’ extinction and ignition procedure. 

The simplest method would be to simply add a button to the battery and turn off the power to turn off a Phyllo. However, we would like to establish a slightly cleaner method. By adding just a few wires, here is what we could do:

  • On the bottom PCB, we add a wake-up button connected to the processor and a wire from the CPU to the wake-up pin of the ESP32. We connect the 5V-regulator enable pin to the CPU.
  • To turn on a phyllo, assuming that the bottom CPU is in sleep mode, we just have to press the CPU wake-up button. The STM32 CPU then wakes up the ESP32 and switches the enable pin on the 5V-regulator to “1”, turning on all the rotating CPUs (main board and processor PCB). To completely turn off the bottom PCB, we have to disconnect the battery.
  • To turn off a Phyllo, we press the wake-up button. The bottom ESP32 sends a signal “power-off” to the main board’s ESP32, which transfers it (via UART or SPI) to the main board CPU and then goes to sleep. The main board CPU sends a SPI signal to each LEDs-driving processor, and switches to sleep mode. Then, the bottom PCB switches the enable pin of the 5V regulator and enters sleep mode. 

We are also considering the possibility of making an ACK chain so that the bottom pcb can ensure that all the rotating PCBs are in standby before switching off the power with the switching regulator, but this is probably not necessary. We will add these few wires in the coming days. We’ll keep you updated 🙂

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