HMC1001 / 1002 / 1021 / 1022 are a series of small magnetoresistive sensors produced by Honeywell. They are widely used in navigation systems, attitude reference, traffic detection, medical devices and non-contact switches. These sensors have a wide field range (up to ±6 gauss), can be configured as 1-axis or 2-axis, and are solid state devices with low cost, high sensitivity and high reliability.