Back to school after the holidays, we ran tests to validate our idea for detecting other Phyllos with IR radiations. Quick reminder, we had ordered two powerful IR transmitters (LTE-R38381S-ZF-U and SFH 4441) and several receivers, some in AGC2 (TSOP2256 and TSOP4856) and others in AGC4 (TSOP4456). Signal management is a little different depending on the type of gain control (AGC): some receivers are more suitable for noise reduction and other lower detection times.
We will briefly go through the IR detection protocol once again.
First of all, Phyllos give themselves a unique identifier by communicating via Wifi.… Read more
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
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
In a previous post we discussed several ideas on how to detect the direction of neighbouring Phyllos relative to a given Phyllo. Our favourite idea in this post was based on a mix of Wifi and IR : the Phyllos would cooperate using Wifi to turn their IR emitters on one at a time to allow the others to detect it using IR detectors.
But this idea raises several problems. The most notable is IR reflections : they could spoof the Phyllos into detecting neighbours in the wrong directions. We thought we would be able to differentiate an IR reflection from a direct emission by comparing the amplitudes, but according to Alexis, we will have too much trouble.… Read more
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