Four similar SMDPLCC 2 (the package compatible with the flexible waveguides we were considering) LEDs: ASMB-MTB1-0A3A2, HSMA-A431-Z50M1, CLM2D-GCC-CC0F0783 and ASMB-BTE1-0B332, all requiring around 20mA
The LEDs for the PCB petals (see our latest architecture post) were to be either the LE RTDUW or the ASMG-PT00, and the LEDs for the top PCB were to be the ASMG-PT00 or one of the four SMD PLCC2 LEDs.… Read more
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
Last week, we thoroughly tested the MPU9250 that Alexis lent us. At first glance, it looked a lot more promising than the TLV493D-A1B6 MS2GO () we tried before : the range is way better ! Unfortunately, magnetic detection is more complicated than we first thought and it looks like it’s not going to cut it.
You can take a look at this post to remind you of the detection scheme we had in mind.
Essentially, the idea is to use electromagnet in every Phyllo that can be turned on and off, so as to detect the Phyllos one after another, and use Wifi or Bluetooth to coordinate.… Read more
Yesterday I set out to test the LEDs we received : ASMG-PT00-00001 and LE RTDUW S2WP. The first is a powerful RGB LED, while the second is an even more powerful RGBW LED. They need to be quite powerful because in order to avoid a blurry image due to the motor rotation the duration of the flashes must very brief, and since the LEDs are flashed only once every 137.5 degrees of rotation that means they are off most of the time.
The goal here is to test under conditions similar to those the LEDs will actually be used in : once every 1/30 seconds, they will be turned on for 100µs using high frequency PWM modulation for the colors, and then switched off again.… Read more
We discussed in our post Generating 3D Models the script I wrote to generate the 3D model of our phyllotactic sculpture. In this script, I start by generating a polyhedron made up of quadrilaterals arranged in a phyllotactic pattern:
Then, my script takes as input a 3D model of a petal and copies it on each quadrilateral:
One problem with this method is each quadrilateral is different, which means I had to slightly deform each petal to fir the quadrilateral’s shape. Figuring the exact 3D transformation to accomplish this seemed a little too time consuming so I used lattices in blender, which are a way to deform objects according to a 3D grid.… 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