Hall-effect Switches and pic Inputs

[andybarrett1]

Hi...

Has any body had experience in using hall-effect switches with Pics.

Are there any design considerations it would be good to be aware off.... I know most switches have Hyst. circuits built in (Allegro A1104) but are there any other rules.

Both hardware and Software advice thank you.

Thanks for reading

Andy

[Dave]

I try to use only open collector to ground output devices with an on board pullup resistor so as not to chance injecting any high voltage spikes on any pins. Hall Efect Switches are much better than mechanical ones as there is no contact bounce. Watch for the ones that source or have PNP outputs as the source of there voltage is the source of there supply. If placed a resonable distance from the PIC input pin lines become great antennas. Most all of my designs however use opto isolators for digital input to elimnate these problems. Even with Hall Efect Switches.

[richard]

the a1104 is a unipole device
where the TLE 4913 is omnipole
if N/S pole detection is wanted

as dave said open collector/drain is the go

[richard]

there is always the ubiquitous UGN3503LT if you want to read analogue mag field strengths too

[andybarrett1]

Just ordered a free bunch from Allegro

Will let you know how I get on.

Thank you for advice....Open Drain Mosfets !!!