One more note, The A1302 is a ratio metric device, the quiescent (No Mag field) is approx Vcc/2. As the other gentleman suggested you might do better with a Hall effect Switch if an On / Off sense is needed, although a pair of those A1302's and containment (pole pieces for shielding) would make a nifty coarse position or X/Y indicator as the output polarity changes with magnetic polarity @ +/-2.5mV per N/S Gauss change in polarity or intensity, A1301's will give a +/-1.3mV / N/S Gauss change. I bought a couple from eBay for $2.00 or $3.00 and had great fun with them. I thought to make a 'unique mag key' with one and an op-amp for level shifting (Decode) small coil of wire (solenoid)/ LM350T (encode) and two Arduino's for encode/decode... I do hope this is useful information...
From the Allegro Data Sheet @ (1.508.853.5000; www.allegromicro.com)
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