First, thanks for the photo analysis. If you're scratching your head, I must have done a decent job processing the image. What you're seeing is actually a mirrored and composite of 2 photos. One taken in clear weather (by my daughter) and the other taken at night on Bulb. The actual lightning photo that I used is here:
As for using a Peltier for lightning photography, I think it might not be the best choice. The peltier would have a time constant that is too large for lightning photography. It's definitely better at the long integration signals and energy measurement, rather than signal detection.
Cool project, but when I saw your portrait on the article, my first thought was, "why is he standing out in a lightning storm?". My second thought was, "From the exposure, that looks like an impressive picture to capture for not being a bulb exposure at night." My third thought was, "is he using the Peltier device as a lightning sensor to trigger the camera?" I didn't see a mention of that and I suspect the heat sink on this implementation might make it too slow to respond, but do you have any idea what kind of responsiveness is possible for a given size of thermopile?
I see that 78RPM has used a rail-splitter component. I didn't know they existed. I always used an opamp set at unity gain and connected between two identical resistors connected to the power supply rails.
I have been designing electronic circuits all of my life, and even I learned something new from this blog.
I agree. This cloud sensing device would make a great addition to Earth Science and Physics classes. I like the compactness of the sensor and the fact the design can easily be packaged to accommodate the user's application. This project reminds of the work Forrest Mims is conducting on atmospheric HAZE using homebrew sensing circuits. Great post and project!
Eric, this had to be a fascinating project and one that obviously gave a great deal of satisfaction when completed. I would love to see university classes teach this type of thinking to student AND provide the hands-on experience building the device would provide. It would make a great semester project if the theory were presented along with the assembly. Great post.
Thanks for the link, 78RPM. I've been tinkering with electronics for most of my life. Admittedly, I'm much better at the mechanical side of things. But how on Earth did I not know about this Rail Splitter/virtual ground technique...??? You have no idea how many bipolar power supplies I've built over the years. I'll definitely file this one away for future projects.
Thanks for taking a look at my project and for the comments on the rail splitter. That's a new device for me. I knew the electronics were not optimal, but I'm much better at the mechanical end of these projects. So your comments and ideas are definitely appreciated.
I like the datalogging idea. I do a lot of deep sky astrophotography. As you can imagine, the best results are on very transparent nights. I mainly rely on GOES satellite images, on the water vapor channels. But that's always up for a little interpretation. I was looking at this as one of the options for measuring the transparency and logging these, when I do my deep sky imaging.
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