raspberrypi:blackoutdetector
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raspberrypi:blackoutdetector [2013/11/10 00:54] – rlunaro | raspberrypi:blackoutdetector [2022/12/02 22:02] (current) – external edit 127.0.0.1 | ||
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==== Ladies and gentlemen, the power source ==== | ==== Ladies and gentlemen, the power source ==== | ||
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+ | I've started with this power source, and my initial idea was to use a simple | ||
+ | resitor to lower the voltage to 3.3V, but when I went to measure the output | ||
+ | given, I received a big surprise: the output was 8V, very far from the 4.5 | ||
+ | expected. | ||
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+ | I've asked around and I found out that you can lower this value in a safe | ||
+ | way by connecting it to an voltage stabilizer. It is a circuit that outputs | ||
+ | some voltage regardless of the input voltage you have. | ||
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+ | In essence, this is made by an integrated cirtuit called LM317, a pair of | ||
+ | resistors and two capacitors. Here is the schematics: | ||
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+ | {{ : | ||
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+ | Picking the values of the resistors is the most complicated thing. To ease | ||
+ | it, I've selected one fixed and the other a variable resistor: by trimming | ||
+ | it afterwars you can fix the voltage to a very precise value. Moreover, I' | ||
+ | discovered how handy is it when the output voltage changed when I' | ||
+ | enlarged the output cable. | ||
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+ | Here is a picture of the resulting circuit: | ||
{{ : | {{ : | ||
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+ | I've bought a box to protect it. Here is the final product: | ||
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- | {{ :raspberrypi: | + | ==== References ==== |
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+ | http:// | ||
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raspberrypi/blackoutdetector.1384041265.txt.gz · Last modified: 2022/12/02 22:02 (external edit)