The first prototype of the electronic board game Helvetios is the circuit that corresponds to one of the arms with sensors and leds. In each cell there is a magnetic Hall effect sensor and three RGB leds, what allows to detect if there is a piece or not over the sell and show the cell colour according to what is programmed in the game mechanics. This is the block design of this circuit:
In this prototype there is only 5 cells, but in the final design of the Helvetios board there will be 8 cells for each circuit. In the board will be 21 led circuits, which makes 169 cells counting the central cell. This size is selected so each leds circuit only will have one TLC5947 led driver, but could be increased in a future by connecting some of these divers in cascade. The distribution of these circuits in the board is showed here:
The PCB design and the 3D renders are showed here:
To develop the control firmware I’ve used an evaluation board for Cortex M3 from ST NUCLEO-F103RB, actually it was a Cortex M0 board but I’ve repurposed it with a new microcontroller and adding an 8MHz quartz so the USB peripheral could work. I’ve in mind to modify it again to change the microcontroller for the STM32F103RC so I’ll have 3 SPI peripheral which will help me to control the three ‘branches’ of led circuits at the same time. It’s mounted in a bakelite board with a male connector for the led circuit and a Raspberry Pi Zero W with a little Oled screen. In the next phase of the project the microcontroller will be connected via USB to the Raspberry due it will include the high level software to control the game mechanics, the ‘game master’.
And to finish some examples of animations that could be achieved with this prototype: