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Create Your Own Bullet Time Camera Rig With Raspberry Pi
sfcrazy writes "A team of extremely creative people have created a really inexpensive bullet time set-up using Raspberry Pis — and the whole set-up costs less than a professional DSLR camera. The rig looks more like the LHC at CERN using nearly half a kilometre of network cables, 48 Raspberry Pis fitted with cameras and PiFace Control. The rig worked perfectly — in terms of doing what a bullet time set-up should do. Raspberry Pis achieved the Hollywood's 'frozen time' effect at a much lesser cost."
48 rpis = 48 * $35 = $1680
48 cameras = 48 * $30 = $1440
48 piface = 48 * $34 = $1632
48 2gb sd cards = 48 * $8 = $384
48 5V PSU = $48 * 3 = $144
Up to here, it's $5280. Not including:
about half a kilometre of network cable
2 x 24 port switches
1 wireless router
custom laser cut frame
shipping
So let's say $6k. You can buy a nice professional DSLR for much much cheaper than that.
The "really inexpensive" part was what I thought was humourous. "costs less than a professional DSLR camera". Math is fun!
So the "best" DSLR right now according to reviews is the CanonEOS-1D X which can be had for ~$5500. Divide that by 48 because that's how many pi complete devices they used and we get $114.58. The Pi that they used was the $35 unit because they needed Ethernet. They also had a $30 camera and a $33 PiFace display on each. We're up to $98... oh wait, they used preloaded SD cards at $13 a pop, and we're up to $111 with no power supply. Fine, lets say that with bulk prices we get PS from the goddamn Loch Ness Monster for three fiddy a piece. Bam, we've hit or target. Or at least we would if we didn't have to factor in networking components, a custom "laser cut" frame, or 0.5km of cable and a days worth of time to crimp ninety six RJ45 plugs.
The TL:DR point is to stop giving us meaningless indicators of how much some shit costs. Just tell us a number. Did you know that this project supposedly costs less than the average trade in value of a 2005 Honda Accord? ($5775) It costs sufficiently less than giving birth to a child ($8802) It even is less than the cost of eating a donut a day for thirty years? ($5962.50 @ $0.50 ea plus 6% sales tax) and that doesn't even factor in the added costs of type 2 diabetes!
So just tell us how much it costs. Everything else is just wasting our time. My apologies if you actually read through my entire post.
For each station, we have (priced at Newark):
$40 Raspberry Pi B w/ NOOBS SD card.
$25 Camera module
$34 Piface display/control (seriously? why? aren't they controlled over the network? why aren't they headless? Oh, right: because this whole project is advertisement for Piface, even though their hardware contributes nothing of value to it...)
Making a total of $99 at each station. That's not counting ethernet cable, switches, and for no obvious reason, a separate 5V PSU for each Pi -- I left that out of the per-station cost, because anyone sane would use one power supply for multiple stations.
Now for $99, I can damn sure buy a cheap digital camera for each station, (and an SD card for each of them, if necessary), and have larger sensors, better glass, and crazy features like not being fixed-focus vs. the Raspberry Pi camera module. Sadly, remote shutter is not a common thing on the sort of cheap camera we're looking at, so some hardware hacking (*gasp*) might be required, and many camera models have issues like automatic power off that will make your life miserable -- so for an arbitrary cheap camera, this is better in some ways, worse in others, and not necessarily better on the whole. But with CHDK, we can beat it easily.
It'd be great if we had $120 a station -- for that money, we can easily rock CHDK. $99 is just on the edge, but I think you can find CHDK-compatible Canons for less (e.g. this one; note that other colors are cheaper, but very limited quantity, and without more research, I'm not sure that any of them will actually have firmware revisions supported by CHDK) -- if so, or if we can agree that the combination of better image quality, extra features, and reduced ethernet hardware, is worth a few extra bucks, you should have two options:
1. use USB hubs with CHDK's PTP extensions to control multiple CHDK-loaded cameras from each Raspberry Pi -- this will allow staggering individual cameras for the true bullet-time effect where the viewpoint revolves around a slow-motion (not completely frozen) subject, as well as the all-at-once mode described in TFA, and any combination.
2. forget the Raspberry Pis, and control the cameras using CHDK's USB remote shutter capability -- this is very simple in the all-at-once case, as you can simply wire 48 USB ports to a single 5V PSU, and switch it on and off. The proper effect is a little more complicated, but still no-CPU-required, e.g. use a single debounced pushbutton to generate a pulse, and clock source + a half-dozen 8-bit shift registers to sequence that pulse to all 48 USB cables. Or use a microcontroller with those shift registers to generate the pulse and the clock -- by varying the clock, you speed/slow the ratio of subject motion to viewpoint motion. Or use a microcontroller with enough GPIO to control all the cameras directly.
I don't think you get it -- each station has a ~$40 RPi-B, a ~$30 5MPx camera module, and a ~$30 LCD+buttons board (which AFAICT serves no actual purpose in this project, but is the product being sold by the people who put this project together to promote that product, so it kinda has to be in there).
You'd use an AVR/PIC at each station to control a point-and-shoot digital camera -- and a $40 RPi would be insane in that role. In this case, they're using the RPi not to control a standalone camera, but to be the mainboard of a digital camera. Depending on the smarts present in that camera module, and particularly on how slow a data rate it's capable of speaking, an AVR/PIC might be able to handle this, but it would be some heavy lifting. From that perspective, it almost makes sense -- if only a CHDK-capable P&S weren't basically the same price and a whole lot more featureful.