how much cpu or two devices

I would like to possibly use virtualhere for tethering a dslr and a small webcam remotely or astrophotography use. Of the available usb over ip software solutions this one seems the most mature and easy to setup. The device I plan to have the server running on is a dlink dir-510L portable router (runs on battery) with openwrt. I have successfully tested virtualhere and know that it works fine with the camera doing tethering with liveview. Obviously to run two devices I will need to purchase a license, which is why I am asking about this here before buying.

First off, since this is a router running openwrt, it will obviously get upgraded to new versions of the distro from time to time. Will the license/serial stay the same everytime I wipe and upgrade the device based on hardware or something? Or is it generated new for each install and then I will have to contact or a license reissue?

Secondly, I don't have any doubts the router cpu has enough capability to do the camera tether with a live view, since people do it with usbip on a less powerful trendnet portable router. However, I do not know how much is needed to get two devices, one of which is a webcam for tracking/autoguidance to run smoothly. The webcam is not extremely high resolution, but it is fairly high fps to keep track of movement across the sky. The cpu in the router is a MediaTek MT7620A which is a mips 24k running at 580mhz. At first glance this would seem like it would be fast enough to handle it?

Thirdly, is there any kind of prioritization for devices. or example if the router is fast enough to almost handle them smoothly ut not quite could the tracking webcam get prioritization over the camera live view, or would this be handled entirely in the router QoS rules on the ethernet side, not within the packet encapsulation?


Someone is already doing this… with virtualhere, so it works and apparently works quite well, looking at the comments. It can be done for around $US50. virtualhere it licensed per server using a serial generated from the hardware so it wont change when openwrt is changed or reflashed or whatever, you dont need a new license or for it to be reissued. I made a build specifically for that guy which helps him integrate it into the router, but its still in trial mode but since most people just connect it to one device trial mode is not a problem.

You must run the client on windows or linux, osx i havent got isochronous (webcam type devices) working yet so only windows or linux will support the liveview.

I multiplex all usb streams into a single tcp socket connection over port 7575 . Mainly usb performance is limited by cpu and latency rather than network throughput so i dont think it would be much use adding a QOS component into the stream.


That helps to know it's all muxed into one connection. The client is going to be on windows so this won't be an issue. I would use the same router as that instructable (I had seen that article), but the dlink one has a 4000mah battery instead of a 2000mah which is more suitable for the long exposures of astrophotography. When you say you made a build specifically for that guy can you elaborate on what is different from the standard ones listed on the downloads page?


I took a look at the DL510 webpage and it looks really good, the ac wifi would be great. Mainly i compressed the binary so it fitted on the router, but i suspect this router may have bigger flash so that router should work with the mipsel binary on my webpage as is. I think that a 580Mhz may be a little slow but its worth a try.


hello snyder!

Igor here, the guy who made the instructable.. :) the biggest issue i am having is connection speed. its limited by the hardware so there is nothing that can be done. transfer speed is at about 1.9 mb/s. Live view is possible, works, but is a bit laggy. I guess that this isnt a problem for astro. Could you please elaborate your tracking system using the webcam? not sure i get it.. you say high FPS, low res.. for a slow moving image like the stars and a lot of small dots, i would expect a low FPS and high res.. got me curious on that one.

the battery is 2000 mah but it works for about 5 hours before it dies... thats withnormal shooting. dont know with constant video stream tough.

Also check if there is the openWRT firmware for that router. I found a few posts talking about the sysupgrade version, (was not able to find it myself tough) and in that case you cant update because you need the factory image first. youd have to compile it yourself.




So the reason the camera for star tracking is low res is because it mainly tracks one or more bright stars in the given field of view. It sends this via usb to a program running on a computer that the guide software that basically tracks the movement of stars across the sky. They move slowly in terms of what would be normal shutter speeds. But astrophotogrpahy is typically long exposure, sometimes 5 minutes or more. So any movement then makes star trails if the mount does not move with the stars. A second cable goes out of the guide webcam to the motorized mount that sends movement controls. Example is this model. This webcam is mounted to the finder scope, while the actual DSLR is mounted to the main telescope. The camers typically run at higher fps (60+) because while things move slow across the sky that are far away, closer object like planets/close comets/eclipses, etc move relatively fast across the sky and require movement instructions to the mount at a quicker pace. The nicer lodestar cameras operate at up to 200fps for example for fast planetary tracking.

The liveview on the dslr is nice, but i really only want it long enough to setup the parameters and then set the long exposure off. After that I can just let the intervalometer do it's thing.

I do see the builds for that router, also there are the MT7620a ramips builds in the repo. I could build myself if needed. The 4000mah battery is the main draw here, as an imaging session can go most of the night. The cables aren't an issue in the summer, but in the winter it's much nicer to be inside a vehicle or building while your equipment is out imaging. Also there is no worries about camera shake from cables moving around, as even the tiniest of shake can screw up a 5minute exposure easily.


I should also note that I'm open to some other solutions for a device. This one just looks like it could be the cheapest. I had also though of something like an intel nuc with a battery or a netbook as the client device with an ad hoc connection to my host running the guide and live view software. I would like to keep it reasonably small since it needs to be portable but the telescope mount is sizeable enough to attach things to. The caveat is that guide cameras output to usb and the liveview on my camera is via usb, so i'm either still using something like virtualhere, or the client device must be something I can remote into that's reasonably powerful. Running virtualhere seems like the more portable option if it's speedy enough.


Did you buy the the DL-510? Is the performance OK with virtualhere?