Speedometer

As explained in this post, Xavier and I worked on a setup to measure the motor speed. We had to laser-print a drilled plastic plate and some fixation for the dev-board with the optical sensor we’ve borrowed from LitSpin (TCUT1600X01). 

Setup

The plastic disk is thin enough to slide between the emitter and the receptors of the optical sensor, and has a small aperture on the edge so that once per rotation the receptors see the emitter and their output goes high.

The optical sensor, which we thought we damaged on Friday, actually works very well. We had some bugs when integrating the dshot code to control the motor’s speed, but very quickly we were able to measure the speed, and to determine the correspondence between a dshot command and an actual speed at a given voltage.… Read more

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