Wednesday, June 18, 2014

The New Parts Arrive

Well, I am happy to say my orders from Aliexpress arrived yesterday with the small piezo buzzers and the light-dependent resistors.  That's the good news.  The bad news was that 13 out of the 20 buzzers were not working.  At first I thought I had ordered the wrong type and that it needed more voltage, an AC power source or something.  Then later I tried another one and it worked! (Albeit very quietly)  I then tested the whole bag and only 7 of them worked.  Disappointing.  However, I did not pay much... but I did not like the failure rate.

Fortunately the LDR worked great so that can be worked in to the sensor board.  I may have to change the compare resistance to capture the best value range on the analog input.  I am going to use this formula

     Pull-Down-Resistor = squareroot(Rmin * Rmax)

Where the Rmin and Rmax come from testing a few of the LDRs for Minimum and Maximum resistance.

So, I have order a new batch of buzzers from Aliexpress.  Since it was hard to tell if I would get the same result (even from another vendor) I decided to try the big lot-cheap price strategy.  So I ordered a lot of 100!  This time it will run me about $8 but I think the shipping will be a little faster (China Air?).  I can't imagine what I would do with 100 buzzers (especially if they all work).

Anyways, I have enough to start work on the new boards.  The first will be a new sound board with pin selection and passthrough headers.  The next should be a proper RGB board with a selectable blue pin. Fun!

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