Thursday 29 August 2013

Ghetto fpv quadcopter: episode 2

Ok, so in my previous blog post, I wrote a fairly comprehensive instruction on how to build a ghetto fpv quadcopter for around £115. It works well. However, just this week I was given a camera module MC495a

I decided to test it and see how it works. 
Connecting the mc495a to our 200mw tx is fairly straight forward. Desolder the simple usb wire from the tx's video out, snip off the connector attached to the rca a/v adapter cable included with the camera, and solder that on to each of the 4 connections on the tx - video, audio, power, ground. Not forgetting the diode at the power. Done. Now, you just plug the camera into that new 4-pin connector. I sealed the exposed back of the camera using tape.

mounting the camera and tx I tried a different approach than the top-mounted 808 #16 camera, as I have thought about the damage to the cloverleaf antenna I have had to repair often, using this method. I opted for a tail-like antenna mounted out the rear of the quadcopter using a simple 'bag-pouch' made from anti-static plastic bag material and a small ziptie. The front, I screw mounted the camera to the front of the quad frame (the screw was a silver screw from the case of the 808 #16 camera).

Using an rca-to-3.5mm plug pigtail cable, connected to the rca audio plugs on the rc305 output, I am able to get audio aswell as video on my controller, using a cheap speaker: like this.

I like the camera, as it is lighter and seems more robust than an uncased 808 #16 camera. It seems like the picture quality, and response time is better too.

Downside is that it isn't recording 720p vdeo to sd card. However they can be swopped over if needed, or I may try a WLtoys v262 in the future, of something that can lift both fpv setup & 808 #16 cam (possibly with a cheap gimbal this space)

I am recording this fpv camera using a cheap easycap dongle on a laptop, using virtualdub software. Works for me.

One problem I am having, is that I have learned to fly fpv by aiming to have on my monitor screen, half sky, half ground. And as such, as the sky is often naturally brighter than the ground, the camera adjusts for light, and makes the ground dark, shadowy, almost un-viewable. As the camera doesn't seem to have any way to adjust light exposure control, I am wondering what your solutions are?

I am thinking:
-Learn to fly with the camera pointing 90-100% ground, when level flying. (Could be risky monitoring level flight)
-stick some kind of graduated filter over the lens, so that the sky is dimmed, causing the ground to be lightened. I'm aware of photography-related graduated filters, but not tiny lens graduated filters. Anyone have experience with this idea?

How do you adjust/mount your fpv camera to get the best light exposure setting?????


Anonymous said...

a camera like this has what is called WDR, Wide Dynamic Range. This feature is supposed to reduce the contrast between ground and sky. That feature should reduce the problem you are having with your camera.

DalyBulge said...

Brilliant! Now all I need is a 2gram camera with WDR setting, 3.3v, and to be cheap as chips :)

DalyBulge said...

Almost forgot... My solution at the moment is to have the camera pointing towards the ground by a few degrees from horizontal. It means I don't see directly in front, buy it's not so bad when you're mostly flying vertically, with the ability to hover at will.

Sarah Leslie said...

Interesting, we could use something like this when working with inertial systems and the electronic order of battle. Always need ways to utilize cameras as eyes when we can not see when developing and manufacturing.