Simple magnetometer

Introduction:
To estimate the magnetic field strength of a coil, I designed this magnetic flux density measuring device. This device can measure magnetic flux density from ±0.01 to 100 mT with an accuracy of 5%.
The main controller of this magnetic flux density measuring device is an RP2040 (Raspberry Pi Pico), developed using MicroPython. The sensor is the MT9101, a high-precision linear Hall effect sensor manufactured by Magnetek, which converts the magnetic flux density at the location of the Hall plate into an analog output. The ADC is the TM7705, a 16-bit sigma-delta ADC manufactured by Tianwei. Data display uses a combination of a digital tube and RGB LEDs. The digital tube displays the magnitude of the magnetic flux density, and the RGB LEDs indicate the direction.
Working Principle:
The MT9101 generates analog signals of varying intensities depending on the magnetic flux density in different magnetic fields. When no magnetic field lines pass through the Hall plate, the output is 1/2 Vcc. With a magnetic field, the stronger the magnetic field, the greater the deviation of the output analog signal from 1/2 Vcc; the direction of this deviation also varies depending on the direction of the magnetic field.
To obtain higher precision data, I chose an off-chip 16-bit ADC, the TM7705, when designing the circuit. While this device can't achieve very high conversion speeds due to ADC architecture limitations, its ability to measure geomagnetic intensity makes it all worthwhile.
To determine the output in the absence of a magnetic field, the device first records the position of 1/2 Vcc through a calibration, then begins measurement. The measured result is compared with the output in the absence of a magnetic field, and the magnetic field conditions at the measurement location are calculated based on the direction and distance of the deviation. (
Working instructions: Measuring the geomagnetic field, facing east, zeroing north, south.
Random thoughts: I had a brain fart when wiring this board and reversed the inputs. Luckily, the TM7705 supports bipolar inputs, although I lost one significant digit.) The RPi Pico I'm using is manufactured by Hezhou; I bought it for 9.9, but now it's 19.9, double the price, and it's still cheaper than the original Pico. The FLASH decoupling capacitors are also a mess, and I feel the program is also a mess, but at least it works.