crwper

I was pretty impressed with the strength of Dual Lock when I tested it. The only thing to be aware of is that it wears a lot more rapidly than Velcro. The stronger variants, in particular, have a specified life of something like 20-50 cycles. Michael

I've just been using a couple of strips of gaffer's tape over the FlySight, securing it on the back of the helmet with connectors facing down. I punch a couple of small holes for the switch and audio jack, then route the headphone cord under the bottom of the helmet. I've heard about a few different mounting solutions. Someone in Europe, apparently, is making a small pouch, and others have used a u-shaped piece of lexan with a Velcro strap around it. I've got a prototype on the way of what I hope will be a low profile, secure mount, but I'll have to do some testing with the prototype before I mass produce it. Michael

The FlySight firmware source and schematics (as well as source code for the two viewers) are now available on the following GitHub page: http://github.com/flysight/flysight In addition, I've started a user/developer wiki here: http://flysight.ca/wiki For the moment, changes to the main development branch are moderated through "pull requests". The plan is to keep the main branch fairly lean for now. Additional features can be developed in a separate fork, and easily incorporated into the main branch later on if need be. What I have in mind is to add a page on the wiki where additional compiled firmwares can be listed and shared. Feel free to PM me with questions/comments. Michael

FlySight doesn't compensate for changes in altitude. Judging by Jarno's response, this has no effect on glide ratio. However, it is something to consider about for vertical or horizontal speed modes. That said, as far as real-time feedback goes, my feeling is that very few people can tell precisely what tone they are hearing. FlySight's strength is not in the absolute values, but in the changes. This is also why there is no compensation for wind. For an interesting demonstration of the ear's ability to detect change in tone, and not so much absolute tone, check out Shepard Tones: http://en.wikipedia.org/wiki/Shepard_tone When viewing logged data after the fact, it may be valuable to correct for these things. I noticed that Paralog seems to compensate for altitude differences in plotted data. Michael

You'll need to get in touch with Klaus and ask for the most recent beta version, I believe. Michael

It should be possible, provided the display has an external power supply. Basically, a custom firmware could control the two audio lines directly, and use them for digital communication instead. However, it would be a pretty impressive piece of work to get it done. One thing I've noticed, however, is that visual feedback is much less useful in fast-paced activities like skydiving, compared to something like scuba. In my tests with a 4-digit LED display, I found that just the act of reading the display seemed to take me completely out of the skydive, although it required no change in the focus of my eyes or direction of my gaze. I think it was simply that the part of the brain which parses numbers doesn't parallel very well with the part that's active during a skydive. Audible feedback, in contrast, seems to parallel surprisingly well. It takes almost no focus to interpret the tones--it's nearly a subconscious process. Michael

This could be done, but without the stereo output. Although FlySight uses a stereo jack, the left and right channels are connected internally, so they aren't capable of putting out different signals. However, it occurs to me that the same thing could be accomplished (possibly more accurately) using different tones for "go left" and "go right". Definitely. At the moment, FlySight's state is pretty simple--you turn it on, and it starts logging/producing tones. However, there's definitely enough information to distinguish "under canopy" from "in freefall", and separate modes could be used for the two states. I've put together a "beta" firmware which allows users to set modes for the tone pitch and rate separately. One of the main drivers behind this has been an idea I have for swoopers. In particular, I think it might be helpful if horizontal speed was indicated by the pitch of the tone, and vertical speed by the rate. This would, in principle, allow pilots to practice landing up high, with a solid indicator of when they are flying level, and how fast they're going when it happens. In the next couple of weeks, I'm hoping to post the firmware somewhere that interested users can download it--perhaps GitHub. Ultimately, I see FlySight partly as a platform for people to experiment with audible indication of position and velocity, and I look forward to seeing what everyone does with it. Michael

The tip and the ring are connected internally in the FlySight, as shown in the attached schematic. This is why mono plugs won't work. Provided you don't wire the FlySight's sleeve to either the tip or the ring, you should be fine. If you're wiring a mono speaker onto a stereo jack, I'd connect the sleeve to one of the speaker's wires, and either the tip or the ring to the other. Michael

With those settings, you should hear variations similar to the demo video on the website. When optimizing your flight, you'll hear mainly subtle changes in a high-pitched tone. These are generally quite easy to hear, but they are definitely more subtle than the full-scale changes resulting from major changes in body position. I'll be releasing an updated firmware soon (along with instructions on how to update your FlySight) which will allow you to control both min and max indicated value. This should allow you to bracket the range a bit better for hard-core optimizing. Michael

Your number look fine. I'm a bit surprised that you couldn't hear more difference in tone. Is it possible you were flying into a significant headwind? The log file is a big help for adjusting the maximum indicated value. You'll need to calculate the glide ratio manually in Excel, but then you can easily find the maximum value actually reached during your jump. Generally, I set the maximum in the config file perhaps 50% higher than my actual maximum. This gives lots of range in the tone, but leaves a little room for changes in wind, performance, etc. Michael

Looks like there is another option for Windows users. The trial version of Paralog will let you analyse a single jump (only the ability to save seems to be missing). The current release version doesn't support FlySight, but the beta version does. If you're interested, contact Klaus (vidiot) for a link. Michael

Solid work! If you haven't already done it, do you mind if I submit this for inclusion in the next release of GPSBabel? Michael

Sorry, I misunderstood. I thought you were suggesting that the FlySight file should be written only with the columns you listed, as opposed to converting it later on. Hopefully, we'll be able to get FlySight conversion into the next version of GPSBabel. In the meantime, one thing I did run into is the idea of "style schemes". http://www.gpsbabel.org/htmldoc-development/styles_intro.html I haven't looked into the details yet, but it looks like you can define a CSV file format using a style file, and then pass this to GPSBabel in order to convert the file. Michael

Unfortunately, the GPSBabel CSV format seems to omit a few pieces of information which I think are important. In particular, I don't see time or velocity data in there. Arguably, velocity can be calculated from position data, but this isn't a very accurate way of doing things. FlySight stores velocities derived from Doppler shifts, which results in much more accurate results. I've submitted a request to the GPSBabel mailing list. Reading through their FAQ, it seems like FlySight's CSV file should be a piece of cake for them to add. I poked around a little thinking I might be able to add it myself, but I think it may be better if a developer more familiar with the project does it. Michael

The file format is unique (or as unique as a CSV file can be), and not available in GPS Babel to my knowledge. Great idea, though. I'll look into it right away. Michael

I am hoping to put together a similar bit of software for Windows, but unfortunately it's a little ways down the priority list. Michael

Got it. If you look at the time column, it appears that the GPS skips one record in the two rows you've noted, so the time between samples is 0.4 seconds instead of 0.2. Distance traveled will definitely have a larger error. The individual positions should be within hAcc, but when you integrate, the error in distance traveled will be something like sqrt(n * hAcc), where n is the number of terms which have been integrated to get that distance. Otherwise, the spreadsheet looks good. Your equation for horizontal distance seems spot on, and I'm happy to see that it agrees reasonably well with integrating the horizontal velocities. The velocities reported by the FlySight are derived from Doppler shifts. Basically, once the GPS has a lock on the satellite's signal, it keeps track of small time differences that result from Doppler shift (i.e. time shifts in the signal due to your motion relative to the satellite). As it turns out, the GPS can do this very accurately, so Doppler-derived speeds are considerably more accurate (and robust) than those based on difference in position. Michael

As LukeH indicated, the CSV file is the raw data stored by the FlySight on its internal drive, and isn't really intended for (average) human consumption. To analyze the data, I'd recommend either the FlySight Viewer or Paralog. However, looking at your spreadsheet... If you want to know your total horizontal speed, the easiest way is to take SQRT(En*En+Fn*Fn). The velocities stored in the file come directly from Doppler calculations in the GPS receiver, and are a great deal more accurate than taking differences in position. Similarly, if you want to know the horizontal distance traveled, you're likely better off to take the sum of these horizontal speeds, rather than the sum of differences in position. Your interpretation of the accuracy figures is more or less correct. The only issue is that it's not really a hard bound, but more like a standard deviation. Michael

Ah, yes. The columns are as follows: time Time in ISO8601 format lat Latitude (degrees) lon Longitude (degrees) hMSL Height above sea level (m) velN Velocity north (m/s) velE Velocity east (m/s) velD Velocity down (m/s) hAcc Horizontal accuracy (m) vAcc Vertical accuracy (m) sAcc Speed accuracy (m/s) gpsFix GPS fix type (3 = 3D) numSV Number of satellites used in fix During the jump, you can see downward speeds of about 30 m/s, which sounds about right. Possibly you were looking at the wrong column? Michael

I can't say for sure with the WBT-201, but the WBT-202 I have uses a ceramic patch antenna with the top on the same side as the buttons and lights. I imagine the 201 is the same. In this case, the best is to mount the unit on the back of your helmet with the buttons and such facing out (probably the way you'd naturally do it). This way, when you're flying, the antenna will be pointing up at the sky. Michael

It's possible. One of the biggest issues right now is probably the sliding switch. It's got a nice tactile feel, but would be very difficult to waterproof. Otherwise, I think a sufficiently motivated user would have no problem beefing up the water resistance on the current model. Michael

It is not waterproof, but I wouldn't be concerned about jumping in clouds and general freefall moisture. If you're coming down from the jump soaking wet, then I'd be worried. Michael

I'm working on a low profile mount for the FlySight, but it'll probably be a couple of months before it's in production. In the meantime, I've had great results with a couple of pieces of duct tape crossed over it, mounted on the back side of the helmet. The unit is very light, so this setup is plenty secure. Michael

Nope, you're remembering correctly. When I calculated the original price, it seems I didn't leave enough breathing room for marketing and promotion. Unfortunately, this necessitated a price bump. I hope I haven't given the impression of any dirty dealing here, as it's not my intent. If you feel put out by the unexpected price change, shoot me an email and I'll see if we can work something out. Michael