Canadian e-geek and nascent YouTuber [Technoyaki] I want to measure a 20 volt signal on his Arduino. One might usually use a voltage divider to reduce them to the 5 volt range of the Arduino 10-bit A/D. But he is not the kind of person who adopts traditional methods. Instead of using two resistors, [Technoyaki] Decided to build one Analog circuit consisting of sixteen resistors, four operational amplifiers and a single 6 VDC power supply.
What is a quantizer? In the usual sense, the quantizer converts an analog signal (with infinite possible values) into a smaller (and finite) set of digital values. The A/D converter is a perfect example of a quantizer. [Technoyaki], Stretch the definition a bit, and use the term to describe his circuit, which is basically a voltage limiter. It decomposes the 20 V signal into four independent 5 V bands. Of course, just use the Arduino Due with a 12-bit A/D converter to almost achieve this (almost because of its low reference voltage, which is 3.3 V). But this will not be so interesting.
Why use all these extra components?Obviously, reducing the number of parts and circuit complexity is not one of them [Technoyaki]The goal. As he described, the reason is to avoid the inherent A/D resolution loss of traditional voltage dividers. In terms of semantics, we want to point out that no bits of resolution are lost when using a divider-to be more precise, you get a bit of resolution when using a circuit such as a quantizer. Not surprising for precision analog circuits, [Technoyaki] Note that there are still some issues to be resolved. Even if this circuit turns out to be impractical, it is a clever concept worth exploring. Check out the video below the break, where he explained the design and his experiments brilliantly.
Although this is not a simple cut-and-paste circuit solution at the moment, it does show another way to process large signals and obtain some resolution at the same time. We have previously written about a similar method of doubling the A/D resolution of the Arduino. If you have any techniques for measuring higher voltages and/or increasing the resolution of the A/D converter, please let us know.