Camera specs for using FPV camera

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erget
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Joined: Thu Apr 04, 2013 6:10 am

Camera specs for using FPV camera

Post by erget »

Hi there!

I'm looking around for cameras that I could possibly use with the Crazyflie. The one that I like the most at the moment is here:
http://www.unmannedtechshop.co.uk/fpv-g ... combo.html

The entire kit weighs 6g, which sounds pretty promising - I've had a tough time finding other suitable cameras that are light enough.

My question is if I would be able to get this running off of the Crazyflie's onboard power supply. Bear with me, as I've got next to no experience with physical electronics ;)

The camer and transmitter require the following voltage:
Transmitter: 3.3V DC
Camera: 3.3-6V 70mA DC

If I'm understanding the specs on the Crazyflie's power distribution, this should be doable, right? The two through hole pads behind the USB connector are the Crazyflie's power output, if I understand that correctly, and according to this link:
http://wiki.bitcraze.se/projects:crazyf ... stribution
the supply after the power management chip is 3.0-5.5V. 3.3V is in that range, so I would assume that the Crazyflie could power the camera. Or am I missing something? The site also lists 2.8V for VCCA as the analog supply voltage, but I'm not sure what that means. Before I invest so much money in the camera and a receiver, though, I'd like to know if I have a chance of getting it running first.

Thanks a bunch for the info!

foosel
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Re: Camera specs for using FPV camera

Post by foosel »

Voltagewise you should be fine, however the current draw by the transmitter module might make this module unfeasible...

Let's see if I can get this math down (it's been a while for me too, so if anyone now reads the following and bursts out laughing, please also correct it and not just roll on the floor ;))

According to the link it puts out 200mW of transmitting power at a consumption of 320mA. The CF's Lipo provides 170mAh (so a constant current of 170mA for a duration of an hour) and flies around 8min on that, so let's assume it has an average current draw of 170mA * 60min / 8min = 1275mA. If you now add a constant 320mA of the transmitter plus the 70mA of the camera on top of that you come out at 1665mA, which reduces flight time to just over 6min -- in ideal conditions that is. The CF will probably draw more during acceleration in whatever direction (the LiPo is rated at 25C constant discharge, which if I understand this correctly would allow the CF to actually draw 4250mA, or 50C == 8500mA in a short burst), the motors are rated at 810mA max each, so the actual flight time would probably be way less than 6min.

After I got my CF I also thought about getting a cam for it and actually have been circling http://www.fpvhobby.com/96-8ghz-micro-combo-set.html since then (I haven't bought it yet). This one has a transmitter outputting 10mW (instead of the 200mW of yours), which of course means less range but let's be honest, you won't fly the CF in such a great distance away from you anyway, and only draws 70mA (link) plus ~70mA for the camera module. So for our calculation above we would be at 1275mA + 140mA = 1415mA, or more than 7min.

So, basically, look for a transmitter with less power (you won't need it is my guess) and therefore less consumption, and you should hopefully be fine.
Image
Also: AR.Drone 2.0 (RC-enabled thanks to self-soldered MiruMod) and Hubsan X4 H107

zak
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Re: Camera specs for using FPV camera

Post by zak »

Just thought I'd throw my idea out to give people another potential option for a camera. Although I really like the look of the FPV Hobby kits (especially the super-tiny sub-nano kit they have), I've got a feeling it can be done cheaper. The cheapest place seems to be Dealextreme who have a 2.4 GHz wireless camera kit for US$36.20, though there are a couple of issues.

Firstly, the camera weight is a bit higher than I'd like at 10 g. I've managed to weigh a pretty much identical camera and found that the power jack makes up at least 50% of the camera weight. This is actually pretty great - I'll have to cut the jack off so the camera can be powered from the flie anyway which will hopefully drop the weight to something more suitable. The second problem is that the camera needs a 5 V supply which I'm planning to get around by using a voltage regulator. These can be pretty small and cheap - Pololu make a few that can output 5 V, all weighing less than a gram (I'm looking at the NCP1402 because it's available locally). Hopefully this will also solve the power-related problems described in this blog post and by tobias in this thread as well.

Unfortunately I'll be away from home for the next month or so and won't get a chance to try it out, but once I've got all the parts I'll give it a shot. Hopefully this will prove to be a low-cost FPV option for the file.

SuperRoach
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Joined: Fri May 03, 2013 2:06 pm

Re: Camera specs for using FPV camera

Post by SuperRoach »

Thanks for the info zak, very interested to see what others do!

With the sub nano set above,
http://www.fpvhobby.com/143-sub-nano-combo-set.html
How difficult would this be to integrate? It looks good from the website information, but I don't know much else about it.

The youtube comment for the video also mentioned they are a "rip off" - is there an alternate website for the same thing?

absoloodle37
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Joined: Sun Jun 09, 2013 3:04 am

Re: Camera specs for using FPV camera

Post by absoloodle37 »

One other concern with fpvhobby.com is that nearly everything they have is 'out of stock'. The weights and performance look too good to be true. I feel like I'm ordering from the back of a Boy's Life magazine (vacuum cleaner hovercraft anyone? Anyone?)

Would like to know if anyone has ANY experience buying/using products from fpvhobby.com.

SuperRoach
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Posts: 96
Joined: Fri May 03, 2013 2:06 pm

Re: Camera specs for using FPV camera

Post by SuperRoach »

Agreed with Abs above, it's odd that most links seem to refer to them when googling for FPV. Got to be careful to check for stuff instock.

Regarding Transmitters, consider this one:
http://www.fpvhobby.com/180-4-ghz-nano-size-vtx.html

20mw, 0.3 gram....
It lists the channels as difficult to change, so hope that isn't a problem.
Image

I've placed an order in for the above, as well as this camera.
http://www.fpvhobby.com/63-1-gram-nano- ... 80tvl.html

The TX I was suprised it was nice and cheap. Actually also bought another one, a 200mw 5.8ghz but understand it's likely going to have too much of a power draw. It can be a backup :)

tobias
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Location: Sweden

Re: Camera specs for using FPV camera

Post by tobias »

You have probably seen it but have a look in this thread as well. An investigation on how to get FPV working well.

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