Makahiya – flexinol & schematic

Hi everybody,

During this first part of the week, I implemented Tanguy’s suggestion in the touch detection algorithm. For now, it works as well as the previous solution and is able to detect all the touches in the samples I’ve in the automatic tests. I didn’t have time to add new tests so I can’t say that tests proved that it’s a better solution for the moment (but I think it is).

On Monday, I did some tests in order to choose which coaxial cable to use because we had 2 different diameters. The bigger one, the one I’d used so far, appeared to be the best, by far: peaks when approching the hand are much more visible. So we’ll keep this one. And we talked with Alexis about the heat sink that we need for the LEDs. As finding information on this topic is quite difficult and as it’s not necessary to know it for the PCB, we decided to take care of this part later, after having finished the PCB.

On Tuesday, we received the Flexinol wires ordered by Alexis. I did several tests with them. To “program” a new shape, a candle seems to be enough. If possible, I’ll test with something a bit more powerful like a torch to see if there is a difference. These tests showed me that it’s harder to use than expected, especially programming a new shape. With the smallest ones (the one we asked Alexis to order), I didn’t manage to program a shape. However, Alexis had ordered bigger ones (thank you Alexis for this), that work better. I was able to move up and down a pair of scissors with them. But they need much more current than the others: 1.3A each.. So we have again a problem with the power supply… We have to think about it in the next days.

By the end of the week, we’ll do some tests with the audio codec embedded in our development board Olimex-P407 to see if it meets our requirements. And I’ll do more tests with the Flexinol.

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