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.… Read more

PCB: step 2

On Monday, I routed the 4×4 PCB I placed on Friday. I choose to put one multiplexer at the top of this cell and another one at the right. So the SDA lines (which come from the STM32, not from the multiplexer) will come from the left and the bottom. I also changed the scheme by removing a pull-up I put between the main multiplexer and the other multiplexers.

I try to use some shortcuts I found such as one that swaps the pins, but after reading the manual, I found that without a change in the part editor, I cannot use it, so I finally change the pins in the scheme

Now, I will copy 16 times this cell and continue routing with the other components

PCB: step by step

On Friday, I continued to place components. I spent some time to put the 4×4 coils precisely (in the same way as for the test PCB. I found some keyboard shortcuts that help me to do this quickly, but of course, I found the best shortcuts on Monday, when most of the work was done. I take a look at Alexis’ work he made on our test PCB and found some toolbars that will be very useful for me.

Now, I will try to place the multiplexer and to route it. Then I will copy this 4×4 grid sixteen times to finish the PCB until placing and routing the unique components.

Ready for a test of PCB?

On Thursday, I went to Telecom for the first time of the week. I took advantage of this journey to print the prototype of our box for the test PCB. But I lack plastic plank for the middle part (in green in other photos), so we need to wait for a week to have it. However, we will have it on time because we won’t have the PCB before.

In the afternoon, I began the final PCB. We found before a component for charging the battery on a USB cable (the LTC4088), that I put in the schemes.

After some hours on it, I finally find how to import a DXF file of our PCB.… Read more

Heavy Lies the GND

Here’s an update on the work done to the PCBs :


We slightly changed the schematics to accommodate for the sensors. We will need to make a small dedicated PCB but this should be fairly easy and can be done in house. As for routing, some slight changes were made like adding bigger areas where routing is forbidden around mounting holes.

We still need to change the connectors between the mainboard and the highway (on the mainboard side) to get the right board stacking height. this should be done soon as the connectors only differ from the others in their height so routing won’t need to change.… Read more

No Main Is Without Fear

Some news about our Mainboard. After some decisions had to be made to finish routing the Mainboard, it is finally ready to be reviewed and prepared for production. Some changes include adding plated mounting holes for mounting the board and passing GND. Some holes were added in order to make balancing the board easier as it will be spinning fast enough that weight distribution will be an issue.

The holes on the mainboard and the Highway PCB need to be aligned which was an issue with connector placement on the latter. Nathan had to get the proper coordinates and angles for the connectors that could fit the mounting holes that we need.… Read more

Bulletin boards

Ready to roll

After a few days (or weeks) of proofreading, three of our PCBs are ready for production : top PCB, petal PCB and processor PCB. You can find the final version of our schematics for these PCBs attached to this article.

We will need 62 petal PCB, 12 processor PCB and one top PCB for each phyllo. As we plan to make 3 Phyllos, it’s a lot of PCBs, but apart from the top PCB, they are all in two layers and quite simple. The tough part will be to connect them together and place them inside the sculpture.… Read more

Some tests before the prototype: Let’s PCB

A Test PCB

Before making our first device, we aimed at having a smaller one to test some components we do not have time to test: h-bridge, multiplexer, etc.

So, I had to complete a Test PCB that Alexis began. We already have chosen the components, and he chose the step-down converter, which we would use for our circuit.

I spend two days for placing and routing this PCB. We had two constraints: to put our coils at a precise place and the hall sensor just under them and to add the other component where there was still someplace. We choose to try to not add a battery since a phone charger can give us a 5V voltage with 1,5A current.… Read more

Lots of IRons on the fire

Since Friday, Xavier and I have worked on the placement and routing of the main rotating PCB. We have a lot of constraints to place the components of this PCB, notably for the IR which is used for the detection of other Phyllos and the reception of the common time reference, and the IrDA, used to communicate between the fixed and mobile parts.


The IrDA would be used to send speed commands from the rotating part to the fixed PCB below, which controls the motor. This fixed PCB will handle the feedback control of the motor, so we really only need to send it a target speed with the IRdA.… Read more