I am seeking guidance on a remote iPhone camera shutter triggered by lightning. It is based on the project described here.
Everything works. But since I am new to transistors (and catching lightnings on camera) I would appreciate some guidance if anything else is needed (flyback diode? base resistor? optocoupler?) before I commit to pcb.
In a nutshell
Lightning HF signal is picked up by wire antenna, pulled down by 3.3 MΩ resistor and centered by a 20 kΩ voltage divider. The variable resistor lets me adjust the output signal somewhat which goes to pin A0.
When A0 input exceeds a hard coded threshold (500), digital pins go high for 50 ms to close the transistor and blink the LED.
The transistor needs to briefly short two leads coming from a hacked earpod remote, simulating a volume up (or down) press on the remote.
The physical switch lets me adjust the sensitivity without triggering the shutter.
Here is a schematic:
(The reason I use a TIP120 is because that is what I had.)
I realize lightning is potentially hazardous to Arduinos, iPhones and human beings. Aside from that, is there anything I should fix?
Thank you most kindly for your guidance.
Any signal from any antenna is AC. You need a diode rectifier to convert to DC. Like any old crystal radio set. Then your Arduino may or may not be able to see the voltage change.
Hmmm, works as is. If I light a lighter (piezo) or get up off my chair (static) or touch the antenna - click.
And that is NOT lightning, is it?
The link the OP provides leads to a fairly plausible project, so simple Imma try it myself for fun.
And after sorting through all the google hits telling me how to figure out how far away lightning is I discover bolt can stab away for an average of 0.2 seconds, which means there may actually be enough time to get the iPhone to take a picture.
Certainly enough time for a real camera to react.
The actual difficulty may be in matching the RF signal to the direction the camera is pointing, particularly when there are multiple strikes in a very short period of time.
@A7711 Actually I plan to include a delaying function. Lightnings can take a dozen or two millisecs to fully build. Testing will tell.
@Paul_KD7HB Absolutely. I am hoping for an approaching front to improve chances.
Btw: This site shows lightning strike locations worldwide in (almost) real time: Blitzortung. Lets you know when it's worth while setting up.
Yes, I have watched it and it misses a LOT of lightening strikes.
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