Bernhards Random Ramblings BACKUP

Remotely controlled train 4837 entering Kaos Jct on a green signal The Silicon Valley Lines Fall Open House is in the box. I had a lot of fun, but as such events go, it was also stressful. The video-enabled Webthrottle worked well for remote visitors, once we got over a major mistake I made when sending the throttle URLs to the first visitor group. After that I got more into a rhythm: Send emails with personalized throttle links to confirmed visitors, have them join on the video conference, give introduction talk, hand off to train master, and while the session is running work on the next batch of emails. At the Audio/Video control stand preparing email notifications for the next session (Photo Credit : Josh) We had planned for running a round-trip session every 20 minutes. That was a bit too aggressive, since it takes a train about 15 minutes to drive the Open House loop. We had pre-staged trains around the layout, so 3 visitors could start with running their train right away. However...

Back in September, as we were gearing up for another full-blown socially-distanced ops session at Silicon Valley Lines, I quickly needed to build another camera car. I had already built a supplementary power supply for James' Dash9 dummy locomotive using a well car and a 10,000 mAh USB power bank. I wanted a self-contained camera car, so I decided to build a cradle for the second power bank I had, and mount the camera on the side of the power bank. That setup became Cam3. This worked, and we used the car in ops sessions since. However, over time it became obvious that for some reason this car had worse wifi reception than Cam4, my original camera design. That's very curious since it's basically the same hardware ... with two exceptions: Cam4 is powered with a JuiceBoxZero connected to a Li-Ion battery, and Cam3 hugs a big hunk of metal. Side by side comparisons showed that Cam3 performed clearly worse than Cam4, even after reducing the network data requirements of the video...

  Last Friday I went to the club layout and tested the Web Throttle code. The code worked, but video quality was terrible. As soon as I tried to get two video feeds off the camera to WebThrottle and OBS respectively, the video streams produced only one image every 10 seconds at best. That's clearly not acceptable for what we are trying to do here. I experimented with camera settings over the weekend at home. My theory was that due to the difficult Wifi conditions in the layout room, we're simply not getting the network throughput we need to get stable video streams. When running two streams at home I found that the PiZero kept a network send queue of more than two Megabyte or more, i.e. mjpg_streamer is stuffing bytes into the network queue, but they are not making it off the device fast enough. Eventually, buffers will overflow, the network code backs off, the queue drains out, and we see skipped video. In tunnel sections on the Welztalbahn, the queue dropped to about one Mega...

Today Dave Falkenburg and I presented a clinic on "Remote Operations at Silicon Valley Lines" at the NMRAx Virtual Convention. The session was live-streamed on Facebook and Youtube . Regular readers of this blog will recognize some of the content of the presentation. There's plenty of new content as well, so I hope it was interesting in either case. Here is the raw recording of the presentation of today's NMRAx linked to the beginning of our talk.

I've been waiting for a couple weeks now to be able to write this post. John Abatecola from TSG multimedia visited Silicon Valley Lines in August and filmed segments for this video before and during an operations session at Silicon Valley Lines. I explain various aspects of how we add remote operators into operating sessions at SVL, including an overview of the hardware, software, and systems setup, as well as pitfalls. This allows us to minimize the number of people in the layout room to enable social distancing.

I've decided to build a second camera car for Silicon Valley Lines Ops sessions, so that we have a spare camera in case there are problems. For this one I wanted to try and use the existing USB battery holder I built last month and mount the Raspberry Pi on the side of the battery. I tacked the Raspberry Pi Zero to a thin sheet of styrene that can slide between the battery and the styrene supports. I built a support structure for the camera that's glued to the styrene sheet the Pi sits on, and fits between battery and car side. Then I carefully twisted and bent the camera cable to make a 90 degree turn so that it it oriented correctly. I could turn the image in software, but prefer to go with physically correct orientation from the start if possible. After taking the photos below, I added another styrene sheet to protect the camera cable from bumps. This setup must be placed in a container well car because it is quite high and completely fills out the modern HO loading gauge. I...

After the business meeting tonight we tested running trains with remote operators and two CabCams. For some time we also streamed the to Youtube Live  and club members are discussing the experience. We had one camera run out of battery just before the live-stream started, so most of the stream is the cab view from a single train. My camera ahead of the train in the video. James mounted his camera in a dummy unit. Looking good!

[ CabCam posts ] When mounting a camera on a flat car for layout videos or remote operators, a common approach is to set the camera close to the front of the flat car, since we want to give the illusion of being in a locomotive cab. Seeing the front of the flat car destroys that illusion. However, doing this has an unfortunate side-effect: Depending on the length of the flat car used viewers now complain that they can't see as much of the scenery along the track as they had hoped. Especially in tighter curves there is a distinct lack of scenery visible on the inside of the curve. The camera doesn't "look around the corner". Part of the reason for this is basic geometry: The car rides on a curve. The center of the camera view is on a tangent off the center of the curved track. Hence, the center line of the camera image and the center line of the track diverge. The tighter the curve, the larger the divergence, the more scenery on the outside of the curve is taking up s...

[ CabCam posts ] For tonight's club meeting I brought the camera to the layout, so that we could test more of the applicability of this on the actual layout. It worked well. Here is James running the train on the layout from his home in the Santa Cruz Mountains. The camera opens up new perspectives for ops. Here's a screenshot taken by another member participating in the video conference. This time I set up in a much more comfortable location in the layout room.

[ CabCam posts ] We're still tuning the software and streaming setup, but the hardware looks feasible. This is a Raspberry Pi Zero W with the Zero Spy Cam and a Juicebox Zero battery board connected to a 2000mAh Li-Ion battery. A completely self-contained camera setup that easily fits on a HO flat car and can stream video over existing Wifi. If I stack the components more intelligently, it fits on a much shorter car, too. During the Show&Tell at tonight's club meeting, we demonstrated the setup at the workbench and on the Welztalbahn. Members on the video conference were able to observe the trip with only a few seconds delay. This worked much better than expected. So far, so good. The real test will be trying this out at the club.