We present a portable polarimeter capable of real-time visualization of partial and fully polarized light over a broad band of wavelengths. Our system utilizes a Raspberry Pi computer with a low-cost data acquisition “HAT” and an integrated photodetection circuit. Wide bandwidth operation is achieved through digital calibration of an arbitrary retardance waveplate presented herein. All mechanical, electrical, and software components are open source and available on a GitHub repository. This completely integrated approach provides an efficient tool for modern optics research laboratories and is well-suited for educational demonstrations.