Anything like this out there for ethernet networks?
you want 1kbps?
We're making an open-source $30 GPS/mesh radio, would like advice
51–60 of 176 posts
Re: We're making an open-source $30 GPS/mesh radio, would like advice
#52How is it offering 'private' communications on the 33cm band? Does this band even offer good performance in hilly or mountainous terrain? These would be short range line of sight only type devices, correct? I'm still fairly new to amateur radio so I could be off. I don't see the advantage of this over something like APRS on 2M, with the exception that you don't need a license.
encryption is allowed for low duty cycle digital usage on that band. I'm also a ham and really into APRS. But not requiring a license is a big plus, also the way these chirping radios achieve their long range with a super high noise floor so the battery life is amazing. i.e. a TTGO TBEAM will run for about eight days on (including the GPS/radio and CPU). And $30 for that board.
I was going to suggest that you look into some of the patents that were the basis for the old Ricochet Networks stuff as its the basis for most of the smartgrid meter tech, but apparently many of them are more recent than I expected and still under the 20 year mark... also might want to post it to /r/amateurradio for feedback... 73 om!
Re: We're making an open-source $30 GPS/mesh radio, would like advice
#53Earlier quoted context omitted.
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…
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 anten…
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.
Re: We're making an open-source $30 GPS/mesh radio, would like advice
#54XBee it's already at an $30 and $15 price point, I think to 'disrupt' you would need to be profitable at a -10x price point. This is my opinion. I'm usually wrong. But you asked.
Re: We're making an open-source $30 GPS/mesh radio, would like advice
#55I worked on a similar project for Motorola and it had limited commercial success.
Very dense topologies need to aggressively handle broadcast storms such as ARP storms. Very fragmented topologies need to handle delay tolerant networking.
In any event, search for "Mobile Ad-hoc Networks" will show work that has been done previously.
Re: We're making an open-source $30 GPS/mesh radio, would like advice
#56Note that there are limits to how large a mesh network can scale, it's likely to start running into problems with several hundred users. You can scale larger by limiting data to short text messages, but you'll probably never be able to handle more than 10,000 users, unless you can find a way to create high bandwidth backbone links between clusters of users. There has been a lot of research on this in the wireless sen…
yes, this is targeted at hikers etc... so typical max mesh size of about 20 and I bet it would dying by the time a channel had 100 people.
Re: We're making an open-source $30 GPS/mesh radio, would like advice
#57I worked on a similar project for Motorola and it had limited commercial success. Very dense topologies need to aggressively handle broadcast storms such as ARP storms. Very fragmented topologies need to handle delay tolerant networking. In any event, search for "Mobile Ad-hoc Networks" will show work that has been done previously.
thanks! yes, we are very delay tolerant and a typical text message (or flooded location update) takes a few seconds to get across our likely max # of hops (which is only three, due to our uhttps://github.com/meshtastic/Meshtastic-esp32/blob/master/d...)
We initially used the RadioHead mesh router (which seems to be a variant of DSR), but we are switching to something else soon. Misc notes here: https://github.com/meshtastic/Meshtastic-esp32/blob/master/d...
Re: We're making an open-source $30 GPS/mesh radio, would like advice
#58XBee it's already at an $30 and $15 price point, I think to 'disrupt' you would need to be profitable at a -10x price point. This is my opinion. I'm usually wrong. But you asked.
> I'm usually wrong.
That's either insightful, or sad... and I can relate.