there is a difference between silos and domains. It’s great for domains to be separated, and independently well-defined. The silos I have seen cause problems are between organizational functions, like “Product” and engineering or “The Business” and implementation teams.
"tiny little cute icons" is already a big problem in UX. Every designer should be testing the success rates of "little icons" against textual labels. If you have to have an animated tooltip on hover that says what the icon does, it's a big red flag.
I agree. If you have one or two very obvious icons it can work. (Although always include a tooltip as well.) However I often see a toolbar full of similar looking icons and it is so hard to find what I am looking for. (I'm looking at you GMail)
I assume partly that designers do that since textual labels require translation, but icons generally don't. What fits perfectly in English often doesn't fit in German.
> I assume partly that designers do that since textual labels require translation, but icons generally don't. What fits perfectly in English often doesn't fit in German.
Except that icons need tooltips, which would require translation anyway.
You missed the second sentance. The length of the translated string is less critical for a tooltip compared to a toolbar filled with buttons.
Imagine when an app is to be translated to 20 languages. Only the original language had the luxery of having a voice in how many buttons fit on the toolbar.
Oh yes, line of sight makes a big difference (also working as mesh helps for forwarding packets). Also we use a very high spreading factor so the bit rate becomes super low (with lots of chirps)
He's gotta be assuming the nodes have clear line of sight and fresnel zone. The maximum distance for the link budget in a perfect situation. In practice it probably cuts off at the nearest rise in the ground or depression.
But they're still cool and I still want some for non-hiking applications. With the very low power idle and low cost they could be set up with solar panels in the tops of trees or in similar high height above terrain positions.
There is probably very low noise out in hiking environments.
Yes, attenuation due to terrain is going to be a killer, but my experience with non line of sight 900 MHz links blasting through trees leads me to believe it would be workable for low bit rate data between a series of hikers along the same trail.
It is sending only location and text messages so intermittent link status or re-tries due to temporarily terrain/foliage obstructions will not cause degradation in service that you would experience trying to watch netflix over this mesh.
You're wrong. It's a mistake to treat terrain and foliage as the same thing. I have extensive experience with 3 completely different, narrowband and wideband, 902-928 MHz radio data systems as well as just playing around in the range with my software defined radios (hackrf, rtlsdr, etc).
902-928 has almost no advantage over 2.4 GHz when it comes to line of sight issues with terrain. In fact, it's more problematic due to the increased size of the fresnel zone. Sure, it does better through trees but a slight rise of ground is just as much of a problem for 915 and 2400. The freq here isn't helping much. It's the chirp and LORA modulation helping the link budget. But no line of sight is no line of sight.
It sounds like you agree 900 MHz will be much better than 2.4 GHz in this non line of sight application so long as the obstructions are trees and foliage and not terrain.
I would expect to be able to send a few bytes between two stations maybe 400m apart through non-line of sight forest with 900 MHz and both stations at the same elevation. Certainly the grandparent quoting miles would be for mountain top to mountain top.
This stack overflow question has some nice pictures of the LoRa "chirps". They use rising/falling frequency modulation to allow operation at startlingly low signal to noise ratios.
(Also, the hardware they're using is fairly generic, and pretty much all the vendors selling them offer them in 915/920MHz and also 868MHz and 433MHz variants. I've seen claims of over 10km range with 433MHz LoRa gear without special antennas or clear line-of-sight...)
LoRa has very peculiar modulation scheme that in the end is not CDMA-ish spread spectrum but an interesting way how to extend straight FSK into spread spectrum modulation with respectable processing gain and interference rejection.
I recall reading that part of the design was so that not only was it good at rejecting interference, but that it also caused little interference to other users of the spectrum.
If someone else's ISM radio is using a specific frequency (perhaps with CDMA or TDMA), a "chirp" that's spears over about a hundred kHz and -20db or so down in the noise is unlikely to bother them, but is quite useable/reliable for the LORA gear to detect.
I used to get about a mile on 900MHz Ricochet radios, one of which was sitting on a chair in the living room, the other of which was sitting on the passenger seat of my car. Around a mile, the usable data rate would fall below 4800bps, and my NMEA packets would stop going through.
I find it entirely believable that a lower data-rate modulation could get better range than that, even on less power and worse antennas.
I actually fly FPV drones and it’s amazing how far I can go and what obstacles I can penetrate with my 915mhz 2W control link with very usable latency (good antennas makes a huge difference as mentioned by others). 2-5km through thick city buildings etc at times.
Hmm... I'm pretty sure MURS allows for this type of traffic as of the last rules revision and would be ideal for this use with the higher power allowance, but MURS is a USA only thing so that kinda limits you if the goal is something that works all around the world.
OP is also talking about using off the shelf LoRa boards and their project is more about the software, so they are stuck with the bands available on the commercial LoRa transceivers those boards use.
