Posts: 1,504 Threads: 83 Likes Received: 944 in 654 posts Likes Given: 2,142 Joined: Sep 2016 Reputation: 24 Hey guys I'm wondering if anyone can shed some light... I'm thinking of adding an on-board DVR to the FPV camera (RC micro Swift clone) on the FuriBee X140, but I don't want to record the OSD info. The OSD port on the camera is unused, so I'm guessing that I should just be able to splice the DVR into the video wire from the camera? Just wanted confirmation that BetaFlight OSD info gets overlaid onto the FPV image by the FC, through the connection to the VTX? Windless fields and smokeless builds ![[-]](https://intofpv.com/images/collapse.png) • Posts: 2,286 Threads: 38 Likes Received: 1,527 in 995 posts Likes Given: 1,881 Joined: Apr 2016 Reputation: 72 You are correct that the flight controller adds the OSD information to the video signal before it passes it to the VTX to send back to you.
The OSD port on the camera is used to change the camera's settings, so I'm not sure what that has to do with adding your DVR?
If you splice the DVR into the video signal from the camera, you'll be placing two loads on the video signal - the DVR and the flight controller. This may, or may not work, so test it on the bench before committing to the modification. The video signal expects a 75 Ohm impedance and adding two 75 Ohm loads to the signal in parallel will result in an impedance mismatch. It all depends on the camera and the two loads as to how well this will be tolerated. Posts: 1,504 Threads: 83 Likes Received: 944 in 654 posts Likes Given: 2,142 Joined: Sep 2016 Reputation: 24 (29-Jan-2018, 08:58 AM)unseen Wrote: The OSD port on the camera is used to change the camera's settings... Oh ok! I didn't get the camera controller with the Furibee RTF model, so I didn't know that was what the OSD socket is for, in fact it only came with instructions for the LED flash sequence the VTX uses to display channel, band and power! (29-Jan-2018, 08:58 AM)unseen Wrote: If you splice the DVR into the video signal from the camera, you'll be placing two loads on the video signal - the DVR and the flight controller. This may, or may not work, so test it on the bench before committing to the modification. The video signal expects a 75 Ohm impedance and adding two 75 Ohm loads to the signal in parallel will result in an impedance mismatch. It all depends on the camera and the two loads as to how well this will be tolerated. Oh right, I hadn't considered la resistance, thanks Mike! I wanted to avoid wiring in series because I don't know how much lag might be introduced. Nothing is ever quite as simple as I hope!  Windless fields and smokeless builds • Posts: 2,286 Threads: 38 Likes Received: 1,527 in 995 posts Likes Given: 1,881 Joined: Apr 2016 Reputation: 72 The right word here is "impedance" and not "resistance". We're talking about an AC signal and once you get into the world of AC, the difference between the two things is considerable.
That DVR seems a little short on information. Does it really have a video input and output? • Posts: 1,504 Threads: 83 Likes Received: 944 in 654 posts Likes Given: 2,142 Joined: Sep 2016 Reputation: 24 30-Jan-2018, 06:31 AM (This post was last modified: 30-Jan-2018, 06:36 AM by Tom BD Bad.) Video signal is AC?! - Just did a search which led to much info. I read a whole page with rapt attention and a face like this  , resulting in the same feeling of lost time, identical to when the Mrs says "Wash dishes blah blah..."  According to this pic the DVR does have video out -  I thought it was video in and video out, I just realized that the other pin on the port is " Audio in"? Windless fields and smokeless builds • Posts: 2,286 Threads: 38 Likes Received: 1,527 in 995 posts Likes Given: 1,881 Joined: Apr 2016 Reputation: 72 It doesn't really make sense does it? My guess is that the DVR is a purely input device and that the picture should label the pins as Audio IN and Video IN. It's effectively the end of the chain. Your only option is to splice it into the FPV camera's Video and Audio signals and hope that the video camera doesn't mind driving two loads. A video signal sure is AC. Here's what five lines of a video signal look like on an oscilloscope: ![[Image: T01CG34l.png]](https://i.imgur.com/T01CG34l.png) Posts: 5,323 Threads: 674 Likes Received: 3,159 in 1,747 posts Likes Given: 2,032 Joined: Jan 2016 Reputation: 139 I think another solution could be assigning a switch to turn the OSD off, and only turn it on when you need to read the voltage?
Some standalone DVR's do have video-in and video-out, but I found they introduce some noticeable latency, and make your video out video look a bit "laggy" and "choppy", especially when are you recording. • Posts: 1,504 Threads: 83 Likes Received: 944 in 654 posts Likes Given: 2,142 Joined: Sep 2016 Reputation: 24 I want to add the DVR on-board the quad so I don't capture 5.8gHz signal interference, OSD in the image shouldn't be a problem but, I wanted confirmation of that. Unseen has raised a good point about the impedance the DVR will add to the video signal though. Anyway, I didn't order the DVR, I thought I would check the camera (Just ordered the Caddx Turbo micro SDR1  ) with the Eachine DVR I already have fitted to my goggles, and see how it goes... Windless fields and smokeless builds • Posts: 2,286 Threads: 38 Likes Received: 1,527 in 995 posts Likes Given: 1,881 Joined: Apr 2016 Reputation: 72 For the minimal price that the DVR costs, there's no harm in trying. That splicing it into the camera's signal will cause an impedance mismatch might have no effect whatsoever. It all depends on the electronics in both the camera and the DVR. If you can get it to work like this, I'm sure it will help others to know that it is possible.
It's one thing causing an impedance mismatch in the output from a video transmitter where the result can destroy your transmitter. The only bad effect from causing a mismatch in a video camera's output is that it might degrade the signal. It won't actually damage anything.
(Two impedances in parallel will halve the total impedance rather than add to it.) Posts: 1,504 Threads: 83 Likes Received: 944 in 654 posts Likes Given: 2,142 Joined: Sep 2016 Reputation: 24 The DVR is still in the basket, I just didn't include it in the latest order. I will give it a go with the next purchases... Windless fields and smokeless builds Posts: 164 Threads: 16 Likes Received: 50 in 41 posts Likes Given: 48 Joined: Jan 2018 Reputation: 5 By no means a cheap option, but I can kick myself for not buying a Runcam Split for this exact reason. I picked up a 2nd hand Runcam HD for $40 (500 ZAR) to solve my "i want footage" craving. If my post helped you...hit the RATE button. • |
