Time and material

LED-driving software

Today, Xavier and I continued to work on the software for the LED-driving processors. We have obtained fairly satisfying results 🙂 

First, we managed to fix the bug explained here for TIM1. 

We had just forgot to set one bit (MOE bit) in the configuration : TIM1 is an “advanced timer” and this bit is mandatory to enable the outputs. As for TIM9, it is actually not available on the dev board we use. But it is a “general purpose timer”, so we won’t hopefully have any trouble with it.

Then, with the help of Vlaya, we use her SPI generation code to test our SPI reception. After a few modifications, this part worked without issues : we can now receive the configurations for the LEDs and the “TOP” to turn them on through the SPI bus. For now, we have time to process the interrupts as they arrive, even with a SPI bus at 1MHz. But we will test this soon while sending configurations for all the LEDs of the processor in quick succession to see if that is still the case. 

We have also added a few lines of code to put the processor in sleep mode automatically, and only wake it up to handle the interruptions. It works fine 🙂

Tomorrow, we will adapt this code for the top PCB, which has one additional LED and doesn’t use the same GPIOs for routing reasons.

PCB newcast

Alexis is working hard and the top PCBs, petals and processors have gone into production. We have added what was missing for the Phyllo’s ignition and extinction procedure (wake-up button and interrupt lines when necessary).

Change of motor

We didn’t mention it till now but last week Alexis removed the built-in ESCs from our black motors (as opposed to our green motors which came without a built-in ESC) and soldered our BLHEli ESC to replace it. 

This has two major consequences : 

  • The black motor is now only 31mm high, so we can place it inside the structure without have to redo parts of the fixed base.
  • We can control the motor in DShot, same as the green one.

After a few mechanical adaptations (the motor shaft screw-thread wasn’t in the right direction), we fixed the black motor inside the fixed base. We had to calibrate the ESC using BLHeliSuite as mentioned here

We cast about for a while to find the best parameters combination, here is our final setup :

After a few tests,with an input voltage of only 10.8V (minimum voltage of a 4S LiPo), we managed to spin the PVC plate, a Phyllo sculpture, and the structure supporting the LED-driving PCBs. Vlaya started the 3D-printing for the PCB-petals support, we will test it as soon as possible 🙂

Stay tuned !

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