Hi, I have a Raspberry Pi camera with switchable IR filter, I want to control this filter with the GPIOs of the Raspberry Pi. I used an oscilloscope (see my images) to measure the switching signal (by default the filter is switched by the led of camera). To make the filter switch in one direction I need to apply 3,3V for about 150ms (no problem so far) but to switch it back (to make the filter go away) I need to apply the 3,3V with reversed polarity. What (easy and cheap) circuit can I use to give a signal in both directions? (So one GPIO in one direction and another for the other direction.
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FJIMG_20180611_140058.jpg
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I think you should control a half bridge with two gpios. Generate the -3v3 with a single inverting charge pump. You don't tell about current needs. There are many cheap charge pump ICs like icl7660 available.
https://forum.allaboutcircuits.com/threads/half-bridge-circuit-with-dual-supply.53364/ googled that for you
Thank you very much, that looks very promising. Current draw should be minimal as it uses a power rail thought for a SMD LED, I haven't measured it though
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