520 Pi Snake
520 : Pi Snake
- Author: htfab
- Description: Voltage divider that generates π volts
- GitHub repository
- Open in 3D viewer
- Clock: 0 Hz
- Feedback: ✅ 1
How it works
The blue circle has unit radius and therefore an area of π units. We can enclose it by a polygon with exactly 3.3 units of area, adding the parts marked red. Using precision resistors that meander through the blue and red areas respectively we can construct a voltage divider that subdivides the the 3.3 V power and ground rails to achieve a π V output.
How to test
Measure the voltage between the single analog output pin and ground. It should read approximately π volts.
External hardware
Multimeter or other test equipment
IO
| # | Input | Output | Bidirectional |
|---|---|---|---|
| 0 | |||
| 1 | |||
| 2 | |||
| 3 | |||
| 4 | |||
| 5 | |||
| 6 | |||
| 7 |
Analog pins
ua | PCB Pin | Internal index | Description |
|---|---|---|---|
| 0 | B0 | 6 | voltage output |
User feedback
- smunaut: Output reads 3.16597 V (but my 3.3V rail reads 3.30595V so if you correct it's 3.16027V output). Measured with a Keithley 2015 THD.