Pic Lab, PIC16, Experiment #23: Saving data to EEPROM before the power off event

I guess, that sooner or later any developer has a question in his head – how do I save the data if the supply shut down?

There are some solutions listed:

  • The reserve battery (the RTC clock, the motherboard);
  • The constant saving to the memory – not nice, the EEPROM has limited cycles;
  • Saving to the external memory – the complication of the PCB and the code;
  • Saving when the lowering of the vdd level is detected – that what I need!
The voltage detector
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Remote control for the fan

It was a hot, really hot, really very hot summer in 2012 in place where I used to live. I bought some cheap fan, though it was quite powerful, but there were two major drawbacks for me:

  1. No remote control
  2. No timer for scheduling switching off, let say at night. And I did not want it to make noise a whole night.
a fan with the remote control
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Voltage supply 12V, 5V for the audio-amplifier

Now it is time to provide an appropriate voltage supply for the audio-amplifier. Since I care about the noise and the amplifier is dedicated to work from the outlet only, I decided to move in the linear stabilization direction.

What do I want?

  1. The +12В voltage for coolers and relay, which in charge of the stand by mode.
  2. The +5В voltage for everything else, I have a lot of “everything else”, so I need to project a lot of different connectors.
  3. Powerful output capable to provide enough of the power for everything I have.
  4. To not forget to put all powerful transistor underneath of the radiators and coolers.
  5. Add outputs for indications and switches.
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Menu for the audio amplifier

Describing my struggles with a menu for my home small project – an audio amplifier. The main challenge is that we have just 3 buttons (the encoder), and two of them are actually not buttons but rotation directions.

First of all, I drafted a block diagram with the logic of the operation (right-left is a rotation direction, down – the button is pressed).

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USB to RS-232 – FT232RL

There are tons of articles out there, but I decided to make my own device at the moment:

I had thoughts to make such a device long ago, but at this point of time, the necessity of having this stuff increased significantly. Initially, I found a cheap CP2102 IC, it was cheaper than the huge FT232RL, which has a lot of redundant for me functions. Then I went shopping (here I’m talking about Belarus like 8 years ago) and realized that for us CP2102 is more expensive than FT232RL. Well, my choice was kind of obvious.

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