Eat to live or live to eat ?

The power supply is extremely important and is quite complicated in a Phyllo since there are so many PCB as well as several voltages needed.

Capacitor reliant power supply

We have 79 LEDs working under 600mA which sums to 48A. As we flash 30 times every second and each flash lasts around 100us, the LEDs are on at most 0,3% of the time. Thus the average power supply needed is 0,16A.

We have decided to rely on capacitors to fully provide the LED power supply. There are two main reasons for this choice. First, the LED are switched off most of the time.… Read more

New Year, new skin

Happy New Year everyone, hope you enjoyed the holidays !!

Today we are going to talk about the latest trends of our hardware architecture.

New PCB disposition to drive the petals

We used to try to drive each LED with its own processor. However we could not manage to get every component to fit on the PCB petals. Moreover, the processors were underused as we barely needed half of their timer outputs. Therefore, further inside the Phyllo, we decided to add a layer with slightly bigger PCBs (let’s call them the petal controllers). They have a STM32F207VIT6 which can drive up to 10 LEDs.… Read more

Ruling the colony of Phyllos

Yesterday we mostly worked out the detail of how we’ll be detecting neighbouring Phyllos.

Without further ado, here it is :

Step 1 : Discovery and identifier attribution

The first step for the Phyllos is to establish collectively which other Phyllos are present. Each Phyllo must therefore broadcast its presence and be given an identifier. 

This step must be repeated regularly in case Phyllos are switched on/off. 

As described in this post, we plan to base the protocol on wifi broadcast: a Phyllo regularly broadcasts its IP over wifi to signal that it is still on. The others register this IP address in a local running Phyllos table.… Read more

Communicating between Phyllos : Who’s Who ?

In order to display animations that flow back and forth between several Phyllo, the Phyllos need first to be able to know each other’s position. 

For now, we have reduced this problem to this : to display animations in the proper orientation relative to its neighbours, each Phyllo needs to know the direction of each neighboring Phyllo. They have no real need to know exactly how far they are from each other.

Associating detection and communication

It is not enough to merely detect Phyllos if the detection method doesn’t allow us to distinguish one Phyllo from another. We have to be able to both talk to a specific Phyllo AND know where it is physically located.… Read more