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Things like controlling robots or playing World of Warcraft.
But what if you just want one weight sensor, not four?
It seemed like if we could use the sensor from a digital bathroom scale, the filtered output would probably be accurate enough to detect the difference in weight from just one beer. For example, this SD Card Bathroom Scale project uses a microcontroller to ‘read’ the LCD by decoding the signals used to drive it.
This was a great idea, and he pulled it off quite well.
You might be able to use some of the same procedures on other types of digital scales.
This voltage across the capacitor is fed to a comparator, where it’s compared to a reference threshold.
They are arranged as two independent load cells, each with two sensors that act as a differential pair.
The front-end amplifies these tiny differences in resistance, and sums them into a single analog signal.
The separation of functionality into discrete analog and digital circuits makes this model of scale quite fun and easy to hack!
This section will explain the process I used to figure out how this scale works.