486 Pi Snake

486 : Pi Snake

Design render

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.

blue line meanders through circle, red line meanders through polygon minus circle

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

#InputOutputBidirectional
0
1
2
3
4
5
6
7

Analog pins

uaPCB PinInternal indexDescription
0A55voltage output