Optical audio and video transmitter - how to make? - Page 1
Forum section: electronics / general

author: Х-50
author_rank: Newbie
timestamp: May 14, 2024, 04:26:07 pm
content: Hello! Maybe I’m asking the question incorrectly in the search engine, but I didn’t find anything about an optical sound or image transmitter. Only the simplest circuits on YouTube, some even using solar panels (!) as a sensor, transmitted sound. Tell me, are there any ready-made solutions? Specialized chips? NOT via optical cable. What is this direction called? So that you can search for something more efficiently? How difficult is it to organize a transmission channel at 100-200 m? at 500 m? A few kilometers away? Thank you very much for your help.

author: Brumby
author_rank: Unknown
timestamp: May 14, 2024, 04:46:07 pm
content: Are you looking for anAV sender/receiver?This is a common function with a lot of commercially available products, especially at the consumer level. Search on that term and see if you can find some that offer what you want.Most offer transmission by RF, some by cable ... but are you after an optical transmission path by,say, a laser beam? It's a little unclear to me.If you are after something a bit more special, please let us know some specifics.Are you after a point-to-point solution, transmit to an existing receiver, etc.Are you working with analog and/or digital inputs/outputs.... and so on.

author: Х-50
author_rank: Newbie
timestamp: May 14, 2024, 04:49:39 pm
content: No. It is to transmit video or audio via an OPTICAL channel - NOT via a radio channel.

author: tom66
author_rank: Super Contributor
timestamp: May 14, 2024, 04:59:23 pm
content: Video requires high bandwidth.As an example is 720x576 digital video with 8-bits per channel YCbCr 4:2:0 subsampled. At 50Hz frame rate, the bit rate is 248Mbit/s with no framing or blanking.If you make it 1920x1080 digital video (1080p) at 60Hz then you need 1.5Gbit/s with no framing or blanking.Don't even ask about 4K120Hz...Now, you can of course compress video. 8Mbit/s using H.264 is quite acceptable for 1080p60 video, but then you need a hardware codec/decoder on either end of the link.You could then use that with a project like RONJA;https://en.wikipedia.org/wiki/RONJA

author: themadhippy
author_rank: Super Contributor
timestamp: May 14, 2024, 05:34:04 pm
content: Quoteand optical is fine t for high bandwidth signals,thats if were talking fiber optical

author: tooki
author_rank: Super Contributor
timestamp: May 14, 2024, 06:02:44 pm
content: Quote from: Х-50 on May 14, 2024, 04:26:07 pmYou want to do video over free-space optics? I mean, yeah, you can do it: an LCD TV and a camera on a telescope!Realistically, free-space optics for data transmission do exist, but the bandwidth requirements of video make it impractical.Why not use an existing radio technology?

author: mariush
author_rank: Super Contributor
timestamp: May 14, 2024, 06:24:51 pm
content: For short distances and line of sight, you could get directional wireless antennasStuff like ubiquiti powerbeam can go up to 25km , up to around 450mbps :https://eu.store.ui.com/eu/en?category=wireless-airmax-5ghzWired ... you can use ethernet to vdsl+ converters to get a connection up to around 2100 meters using a single pair of wires :https://www.amazon.com/dp/B01BOD8C9W/Speed will drop the longer the distance, down to maybe 5mbps at 2100 meters.But for $200 you can probably get nearly 1000 meters of fiber, and a couple ethernet fiber converters are maybe $15-20

author: Х-50
author_rank: Newbie
timestamp: May 14, 2024, 06:32:43 pm
content: Cable (neither optical nor copper) is not an option - the device needs to be mobile indoors

author: mariush
author_rank: Super Contributor
timestamp: May 14, 2024, 06:41:03 pm
content: Then you could have a 3G / 4G modem and send compressed stream through the mobile networkor you could go and use transmitters and receivers like the ones used on drones and other things..some examplesTransmitter and Receiver HD Video and Audio Signals Over 5.8G Wireless up to 200m for $50 :https://www.alibaba.com/product-detail/Hot-Sale-Wireless-Transmitter-and-Receiver_1600872787985.htmlor up to 800-1000mhttps://de.aliexpress.com/item/2007853394.html?gatewayAdapt=glo2deu

author: madires
author_rank: Super Contributor
timestamp: May 14, 2024, 06:59:54 pm
content: Li-Fi (https://en.wikipedia.org/wiki/Li-Fi)

author: tooki
author_rank: Super Contributor
timestamp: May 14, 2024, 08:14:27 pm
content: Quote from: Х-50 on May 14, 2024, 06:32:43 pmSo i ask youagain:what is wrong with existing radio-based technologies?

author: SiliconWizard
author_rank: Super Contributor
timestamp: May 14, 2024, 09:12:29 pm
content: Quote from: Х-50 on May 14, 2024, 04:26:07 pmOh really. HDMI over fiber has been there for quite a while:https://www.techreviewer.com/learn-about-tech/hdmi-over-fiber-optic/No need to reinvent the wheel here, unless this is for sheer fun.

author: tooki
author_rank: Super Contributor
timestamp: May 15, 2024, 08:56:26 pm
content: Quote from: SiliconWizard on May 14, 2024, 09:12:29 pmOP has stated multiple times, including in the initial post, that it cannot use cables, including fiber optic.

author: tom66
author_rank: Super Contributor
timestamp: May 15, 2024, 11:07:59 pm
content: OP also needs to be clear over what they are trying to actually do.Since they are stated to be from Ukraine is this related to the war effort? That may inform solutions. For instance, it is clear that the radio-controlled drones are being jammed in some areas, reducing their effectiveness. I can't imagine making an optical drone solution work, but I could imagine an optical link between a detached battlefield unit and a base, if it is done carefully to avoid observation by IR cameras etc.But if it is not a military thing, then there are less reliability/covert operation concerns. If it is military, it is probably not suitable to discuss too much in public and OP should be careful about what they do post.We need to understand...- Digital or analog video?- What resolution/frame rate?- Is compression/decompression feasible?- Is it line of sight or does it need to work over a wide possible range of angles? (This last part is very difficult for light transmission.)- What technologies are available - are we talking hobbyist project or something with a serious budget...

author: BrianHG
author_rank: Super Contributor
timestamp: May 15, 2024, 11:39:58 pm
content: Quote from: tom66 on May 15, 2024, 11:07:59 pmThe cheapest smoke grenade or smoke flare would kill your link.

author: BrianHG
author_rank: Super Contributor
timestamp: May 15, 2024, 11:44:00 pm
content: Quote from: tom66 on May 15, 2024, 11:07:59 pmThis with reflections will kill anything in the video band unless you go low res, super .x265 compressed down to something like 100kbit / sec. Otherwise, you want direct line of sight, preferably focused with lenses or parabolic dish to get above 1megabit per sec.Otherwise, you will be stuck with lasers and the rules/regulations and safety concerns there.

author: mariush
author_rank: Super Contributor
timestamp: May 16, 2024, 07:09:20 am
content: I remember watching a video on Youtube a few days ago where they were testing drones that received updates and commands over optical fiber, through a hair thin fiber cable up to a couple miles / km long.The drone had a carbon fiber or some aluminum thin bar at the bottom about 1-2 meters long to keep the fiber away from the fans , and they put a some fishing weights (lead or something) on the fiber in a few places close to the drone to keep the fiber down near the blades of the motors but otherwise the fiber was so light the drone could hover and be guides around that 1-2 mile length of the fiberThey already do it with anti tank rockets , guided through a fiber cable going up to 5.5 km :