Today Xavier and I prepared the setup for the integration of the speed feedback module and the Dshot sender, and the test of the hall sensor :
There is a circular magnet lended to us by Touch at the end of the screw. It generate a magnetic fields in a radial direction, which will therefore point towards the breadboard. It is pretty powerful so we hope it won’t constantly trigger the hall sensor.
The hall sensor we will be using is the TLE4964-4M. It is a pretty basic hall sensor with three pins (VCC, ground and output), which outputs a low value when the magnetic field exceeds B_OP , and goes back to a high value when the field drops below B_RP .… Read more
I’ve been working on coding a section of a speed feedback system since Thirsday. We need a way to frequently measure the motor speed for two reasons:
To adjust the motor speed if it deviates from the target speed
To compute the precise time at which we need to flash the LEDs
To accomplish this, we have optical and hall sensors (we will use the sensor that gives the best precision) hooked up to our rotating PCB and our bottom fixed PCB. The rotating PCB is the one sending the commands to flash the LEDs, and the bottom is the one sending Dshot to our ESC.… Read more
As mentionned here, we will use 62 LED mounted small “Petal-PCBs” and 12 “processor PCBs” to drive groups of 4 to 7 Petal PCBs. Now you might be asking “how on earth will you assemble all these PCBs and solder all the wires involved on a structure rotating at 30 rotations per second ?”, and that would be a fair question…
In my last 3D printing post, I showed you a sculpture printed with the new translucid filament we bought, and a first test gluing a filled petal to the shell.
The last shell had some major flaws due to wrong print settings, but we fixed it and printed another one:
As you can see this one has support structure on the outside, this type of support is very easy to remove. The shell also has some support structure inside it, as with our first shell. It might be possible to remove these structures with acetone steam : acetone steam can be used to smooth a 3D model printed with ABS filament, and since the structure is made up of loose and messy filaments steam acetone might remove it, or at least smooth it.… Read more
You might remember we printed a Phyllo shell with success a week ago. The material we used for this shell however was not meant to be translucid, but actually phosphorescent. This meant our shell was not as translucid as it could be, and it’s phosphorescence was also problematic since we want a high contrast between the phyllo when lit with inner LEDs, and when not lit by any light source.
We therefore ordered a more suitable 3D filament. This time the result for the shell printed with this new filament was not as successful:
The deformation on the first picture was probably caused by the temperature of the nozzle (from which the filament goes out) being too low, which caused the printed raft below the shell to detach itself from the platform.… Read more
Since thursday I’ve looked into how to implement the wifi communication we need between our phyllos (see Ruling the colony of Phyllos ). We need a way for multiple Phyllos next together to broadcast data between themselves, and a way to communicate with the Phyllos from a smartphone or computer (for instance), and we will be using a ESP32 dev kit C integrated in our Phyllos.
Data exchange between Phyllos
The rate at which the phyllo need to exchange data doesn’t have to be very high at all: we just want to exchange small messages such as “Here is my ID: xxxx” , or “Start animation X at time T”.… Read more
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
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
Although our initial plan to light the petals was to put waveguides between the petals and LEDs placed on a flat rigid PCB (see “About LEDs“), Alexis recently told us using flexible PCBs might be possible.
Flexible PCBs could be placed directly on the inside of the demi-sphere of the sculpture, thus avoiding the use of waveguides and ensuring a good luminosity. Their drawbacks however includes a high cost and the fact that Alexis hasn’t yet used them for previous projects.
Using flexible PCBs, our idea would be to take advantage of the symmetry of the sculpture and place identical PCBs along each of the 13 spirals.… Read more