Fig. 9: Assembly of the celestial compass sensor.
From: Celestial compass sensor mimics the insect eye for navigation under cloudy and occluded skies
a Block diagram of the polarisation axis analyser (PAA) printed circuit board (PCB). Red lines represent positive voltage, blue lines are bias voltage, and the black line is ground; the rest are as indicated in the figure. TIA: trans-impedance amplifier, MUX: multiplexer, PGA: programmable gain amplifier, ADC: analogue-to-digital converter, I2C: inter-integrated circuit. b Schematic of the TIA circuit. PD: photodiode. c Front (left) and back (right) images of the PCB. d Picture of the photodiodes. e Four photodiodes on the PCB, and (f) in the 3D printed casing with polarisation filters attached. g The array of PAAs and the camera mounted on the 3D-printed caddy. Numbers denote the identity of each PAA and the order in which their output was read. h The acceptance angle was measured using a torch; the average response distribution of the photodiodes was estimated by using data from photodiodes 3 and 4.
