I’m getting ready for a vacuum test tomorrow at the central laser facility. I want to film from within the target chamber. This poses a few problems, one of which is that it is under a very pure vacuum.
The main problem with this is that things overheat in a vacuum, there’s no air to radiate away heat, and camera chips get pretty hot.
The other problem is that GoPro cameras only like to run off a battery. But I’ve just found a couple of ways around this. Firstly I just bought a new GoPro hero 3+ which can run straight off the USB with no battery, my slightly older GoPro 3 black won’t without a battery installed. So I also just got a DC coupler which makes the older Hero 3 work without one (it’s a Power2000 Chinese thing off eBay, came from the USA with free postage in about 2 working days which was amazing)
Not having batteries in the cameras is essential as even though they’ll possibly survive, they may outgas (leak gas) after a period of time. This will cause big problems in the chamber which has to be completely pumped down for hours at a time.
The final problem is controlling the cameras. They can’t be controlled manually, though there are hacks which involve hard wiring cables onto the camera buttons. The built in wifi with an iPhone app can’t be used as I can’t be in the chamber (there’s a lot of radiation when the plasma gets created), also the chamber is a Faraday cage - ie nothing gets out so no signal escapes that room.
So I just found an amazing bit of software that controls the camera via wifi from a mac (www.pionpion.fr). A mac can be placed in the chamber and linked to the camera, this in turn could be controlled from outside the room via Ethernet.
The heat issue is still there. I’m hoping that the camera will shut itself down before it cooks itself (it’s supposed to!). To try and reduce the heat build up I’ll see if I can attach it to the chamber wall with some metal sheet or braid. I know copper braid is supposed to work well, but copper may also be an issue (heavier metals can become very radioactive because of the plasma). The wifi app lets me turn the camera on and off as well as starting/stopping it, this will help prevent heat buildup. I can also get a live preview from within the chamber.
There is also the issue of the electro magnetic pulse that gets created by the plasma. I think there are ways of mitigating this too.
We’ll find out tomorrow !