Tag Archives: update

The Fan Controller Wrapped Up

Yesterday I found some time to put the fan controller in a casing. I used a very cheap no-name case with the dimensions 130 × 68 × 44 mm. First I drilled some 2.5mm holes into the lid, and fastened the Arduino board on it using M2.5 spacers. You see the bottom of the case in the photo – I mounted everything top down, because this simplified everything.

I experimented with the spacer size, until I found the right height, so the display is more or less at the same height as the case bottom. Next I put very small bits of double sided tape onto the corners of the display and put the case bottom on top of the lid. After removing the bottom, the exact position of the display was marked at the bottom with these double sided tape bits.

First I drilled four holes at the expected corners to see the position from the other side. Next I used a Dremel tool to cut the rectangle out of the case.

As usual: This was my expectation of the result… 😉

lucky-resistor-2

…, and this was the actual result:

lucky-resistor-3

No, seriously, I did not expect much. I just hoped the controller will fit into the case and I cut the rectangle at the right place. So, this worked out very well.

Using the TDA 7052 as Amplifier

The LM386N-1 I used before worked well, but has some disadvantages. There was a hearable distortion in the sound and I needed more amplification to create the required loudness.

I found the TDA 7052 chip, which was formerly produced by Philips, but now by NXP semiconductors. It contains everything required for an amplifier. You just have to supply power, the input signal and there are two outputs to connect the 8Ω speaker.

The updated schema looks like this:

Amplifier 2

I also added a trimmer to adjust the volume of the output. The value of the trimmer is missing in the schema. I used a 47kΩ trimmer, but a 10kΩ trimmer will work fine as well.