How do I set up a mobile wifi router (LAN), and a wifi windows machine?

We are a collective of dancers and bicyclists that organize huge bicycle rallies up and down the west coast. There are dozens of bicycle sound systems on these rides, and we seek to send an airplay audio signal to everyone's smartphone with wifi.

The software of choice is Airfoil.  For it to send audio, it needs to be installed on a windows or mac computer (not cell phone or tablet). Smart phones can then receive the audio signal.

I need help designing a road worthy wifi router and windows machine to be the moving hub of this wifi broadcasting party. Extra points for durability, signal strength and thrift.

Please be detailed, because I am only vaguely knowledgeable of wifi, and I'm not that bright.

Please note that I am well versed with other options for sending an audio signal. I have reasons for being this specific.

Without your help, I would acquire a used netbook with a solid state drive running windows (maybe about $200), grab a wifi router (I have a few older ones lying around) run it all on an inverter and give it a go. Because I am a mac guy, I don't know how to do anything, like how to set up a local area network.... (I usually jam in a cable from a high-speed modem).... we are not doing that on a bicycle, so I'm a bit fuzzy on that part.

I am well versed with power supplies, and willing for the range to be less than ideal at first... (that can be improved later)
I am just looking to get a trial of this system up and running.

I am most appreciative of your help, and I plan on writing a full article on what I've learned, if successful~

Thanks!!! Tor

PS, Photo not of me, but these people are obviously awesome, and will love what we are doing.

Picture of How do I set up a mobile wifi router (LAN), and a wifi windows machine?
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tektig5 years ago
What a cool idea. Since the hardware parts/points have been covered pretty well I'll put in my two cents about the networking side of things. Some thought should be put towards how you want to set up your router security. You'll obviously want an open (dynamically assigned address (i.e. dhcp assigned)) wifi network available (humorously named of course) for the folks consuming your output but you won't want any one accessing your server or router directly. For this you'll want to have the server address consistently/statically assigned on a different subnet then the guests/clients. Open only the ports that you need to between the guest and host subnets, have a way to manage your server while respecting that networking boundary (monitor, keyboard, and mouse directly connected to it?) and you should be good. Messing with the QoS (Quality of Service) might also be a good idea. You should be able to do all this with a stock (depending on make) or custom-firmware on your router. I would recommend dd-wrt, open-wrt, or, tomato in the way of custom firmwares (not that difficult and you'll have a more featureful router afterwards). Also be aware my response is rather sparse compared to the amounts of additional detail I could go into but those are the thoughts that come to mind reading your post. Hope this helps.
torclausen (author)  tektig5 years ago
I just noticed that my free found router is exactly the router that the poster "frollard" actually recommended. Cool! I notice that the antenna can unscrew. neat.

torclausen (author)  tektig5 years ago
What a wonderful answer. You spoke to the part of this project that is most concerning to me. Thank you. I have an linksys wrt54g that was in a free pile. (wireless-g 2.4 ghz) Is this usable, or do I need to purchase a router for this project. I would like to use a good, mainstream router that I have the most possibilities of boosting its signal.

I am imagining that I will plug the router in and somehow access it via this computer that I will also acquire... and with some sort of password, reset the programing on the router.

I plugged a 12vdc battery into the router (it wants ac, but my father says that most things that want ac can actually run fine on dc). It fired up and show a locked network name, requiring a WPA password. I held down the reset button for 30 seconds, and when I went to, it responded "the site said tomato"

It would be nice to test this whole thing with my mac laptop first, just to see if it works. Let me know if you think the this linksys can work for the project.

torclausen (author) 4 years ago

There is a new app on the market with the coolest subtitle..... "together we are loud"

Seedio has answered our prayers, sort of.

Its only for iphones,
It seems to get glitchy when you really push it outdoors.
Setting up the router has taken time.
We have no internet or G3 while on it

But man is it cool. It perfectly syncs our music and attempts to manage people coming and going on the network.

I will attempt to post here when I get more hands on info.

Check it out!

jbrown795 years ago
i hope you got this whole deal worked out in the last 6 months. i've enjoyed reading the problem and some of the intelligent answers. I know nothing of the softwares you've mentioned. i've never even used a mac. what i do know and love is the WRT54g running DD-WRT one thing i didn't see mentioned was within ddwrt's settings you can change how many connections. generally for peer sharing you want more, for steadier speeds on regular web, you want less.
all the antennae i've seen in this thread are yagi. you may get better results with proper use/orientation of directionals like biquads. if you all are going down a road together, you want the transmission to hit 50 yards ahead of you, and 50 behind. but if you only need 10 feet left or right, you should use a directional antenna.pointing one in front of you and one behind you should get most as long on same stretch of road. they are easy enough to make, i did it successfully on my second attempt. and most materials can be scrounged.

also with a number of the routers, you could get some of the other people to carry some gear. i saw it mentioned previously. you could have multiple people in your caravan carry just a router with a 12v power source. set them all as repeaters on same network. no additional computers needed for added routers. expansion of transmission limited to how many wrts you can find.

one thing that i think needs to be made point of fact is the dc adapter for the lynksis puts out 12v 1amp. so as been noted easiest thing to do is cut cord and attach to a car battery, or 12 v drill battery...
torclausen (author)  jbrown795 years ago

Thanks for the comments. I will pass this all on to my companions that are working on this. The problem they are having is that the airfoil software has a glitch in it, in that when one of the receiving iphones goes out of range, it knocks the whole system out of whack for a spell. We need to use this airfoil, because it works with iphones and deals with the delay that would ruin the sound.

The main lady is on vacation overseas, so we will pick it up in a few weeks.

Thanks again for reading this!


ps, I just listed a new question on out LED dance floor.
dtommyd5 years ago
A few points that may have been covered so forgive me for not reading 30 posts.

The router - id use a wrt-54g link sys and put the dd-wrt firmware on it. This router (I'd get a version 1-3) first has external antennas so you could upgrade the antenna to a bigger omni or a directional . I'd hang it as high as possible. You can also go into the dd-wrt firmware and boost the signal. Another important reason to use a wrt-54g router is that it runs on 12v directly and is very forgiving on the current. I've run one from 10v on up to 14.

The stream- while I don't use airfoil, iTunes slows you to stream to multiple airplay devices at once. You'd go into iTunes to tell it to send it out to any AirPlay device it sees. The part I'm confused about is they can't click a button on their end to get the iTunes airplay stream. That's up to you to send it. Seems odd but if that's your plan the I guess you want it that way. There are however some cydia apps that can make an iPad or iPhone appear as a airply device. (jailbroken app). Maybe something has changed but you'll have to check into it.

Delay - every device has a bit of a lag. Your going to get an echo no matter how hard you try. That, coupled with the selfish speed of sound can get weird too. (by the way - someone out there needs to make an app that can use your phone to correct delays (iPhone mic could hear it and delay it so it syncs).
torclausen (author)  dtommyd5 years ago
airfoil corrects for the delay nicely, but it has some problems. if one of the people receiving the stream leaves the signal area, the wifi drops down to a lower signal to try to keep it, then eventually drops the person, and messes up the whole stream for a spell until it recorrects itself. We are working on it with the airfoil people. wish us luck.

The delay has to be addressed or the whole thing isn't worth doing.

thanks toomy for your comments
Not sure if your trying to cover an acre or 10 but with the wrt54g with dd-wrt you can turn up the power, add a bigger antenna, and add repeaters that can turn it into a "mesh" type network. You can pick up the routers on ebay for around $25.

Are you sure we can't talk you into an FM transmitter? :)
I have sort of this vague memory of trying to do something audio related, with a computer that was being powered by an inverter.  I think I was trying to do some recording, but it just did not work at all while the inverter was turned on, because there was this awful 60 hertz buzz that sort of leaked out of the inverter, and into everything else.

For that reason I would recommend finding a PC that can run from 12 volts DC, and just run that from a 12 volt lead-acid battery, the deep cycle kind rather than a starting battery.  I have seen at least one EeePC(r) brand netbook that ran from 12VDC, and also some Wyse(r) thin clients that ran from 12VDC

Regarding wireless routers, most of the wireless routers I have seen want 5 volts DC, and to provide that I would recommend a DC-to-DC converter to convert the 12 volts to 5.  The only problem with that is some of those are kind of noisy too.  The DC-to-DC converter has an oscillator in it, and sometimes you can hear it leaking into your audio.  Nonetheless, I think that noise, will be easier to deal with than the 60 hertz noise that comes with one of those inverters for making mains-like 120 VAC. 

A circuit using a linear 5V regulator, like the the 7805, could of course be dead quiet, but a linear regulator necessarily wastes power.  The regulator would use more power than the router, with the numbers being approximately (7/12) + (5/12) = (12/12) i.e 7/12 of the power dissipated by the regulator, 5/12 dissipated by the router.

Also be sure to actually measure how much current (in amperes) all these devices are using, so you can get some realistic estimates on the amount of battery capacity ( in ampere*hours) you will need.

torclausen (author)  Jack A Lopez5 years ago
We ran into problems, and we had great people working on it. Apparently, this type of network will require synchronized streaming when the clients aren't stationary. And this is complex they say. They told me that I can look up hidden node problem and read more. If anyone knows what this is, and has two cents to add, I'm all ears. The project was going very well until now. We connected easily, but when numerous people connected and started walking around, bad things happened.

torclausen (author)  torclausen5 years ago
Now its looking like the software Airfoil is causing the troubles... stay tuned.
Justdoofus5 years ago
Well, since you want to run your wireless modem without any sort of mains power, cut off the end of the AC-DC converter that changes 115 to 12 v or whatever voltage needed to run the modem/router.. and run it with batteries.. I did it with mine, I converted an old linksys router, and ran it in my van... Mobile WiFi connection. .. Btw, your netbook would last without an inverter, that is one inefficient way to power both of them with bulky batteries.
canucksgirl5 years ago
If your mobile, a regular wifi router isn't going to work. They are normally set up at a permanent location and then your computers/devices can connect wirelessly within a limited range.

Here in Canada, we have options available for mobile internet that runs through a cell signal and with a simple, small USB stick, you can connect to the internet on your computer no matter where you are. So I would recommend that you look for something similar from an ISP in your area. Just be aware that with this kind of setup, you'll pay more for internet than you would at home, but it gives you the full, mobile flexibility that you seem to need.

Your only other option would be to connect to free wifi hotspots along your route, but you'll be limited to when and where you can find the access.

I hope that helps.
The unanswered question is "does the router net internet access, or just local network access to the server on the netbook?"

if so, no internet required, then its just connect the netbook to the same wifi network and start the server up - anyone on the wifi lan (not wan, there is no uplink to the internet) will be able to see the server. If it's proper multicast, it will only take 1 copy of the packet stream to hit everyone on the network, so no bandwidth cap issues either.
From what I've read, in order for Airfoil to work ALL the connecting devices have to be on the same wifi network, and the host can select the devices that can connect after launching the app. The problem is, their travels up and down the west coast, and having a reliable wifi network... (unless I'm missing something?)
just a powerful router (wrt54g with range boost antennas, you can turn the tx up from 20mA to 200mA...since its all outbound that matters it would be a good thing (if illegal)
torclausen (author)  frollard5 years ago
frollard, I've heard that turning up the power on these routers can burn them out quickly. Do you have any feel for what is too much?
20mW (I think) the default is max legal operating power....
Yes, overpowering it will kill it sooner, much like a light bulb burning brighter -- but start with the default and boost a bit at a time if you are running into problems.
torclausen (author)  frollard5 years ago
frollard.... the wrt54g.... the antennas that you speak of, are those just the stock ones I see on the retail photo, or something you add to the stock version?
Can I read how to turn the "tx" up an order of magnitude? Somewhere on this site?

I think they were called "rangeboost" for a while - high gain antennas, about 30cm long as opposed to the default 15cm...

You need custom firmware on the router; DDWRT - it's free and there are TONNES of instructions if you search for them. It's a bit more involved than the stock firmware, you can customize anything, but it allows you access to hardware level controls like %signal output - allowing you to boost your transmit to several times normal.

I would avoid the inverter entirely if you can help it - feed your 12v straight into the router (most take 12v iirc) and the laptop you should be able to find a 12v charger for it - again, reducing rf noise increases your chances of success when dealing with wifi.
torclausen (author)  frollard5 years ago
Is this what I want?
they'll help --
is the no-name made in china version for 1/6 the price. (works identical)
Wifi is just a networking device for tying computers, or phones, together. It is capable of sharing a internet connection but it's not required.
Another example, I have a second wifi router that we use for gaming LAN parties. Everyone is present and we are only playing with each other. Everybody connects to the router and then we can play our games together but the router is not connected to the internet.

In this day and age a wifi connection without internet is unheard of but wifi routers are just wireless versions of the old wired network routers that were in use before broadband internet came around and allowed shared connections (dial-up anyone?).
I was under the impression that Airfoil needed an internet connection and not just the devices in the network... (obviously I was wrong). Which then begs the question of why the OP needs to use Airfoil at all? With a Mac and the AirPort you can share music through iTunes to the devices, and don't need a secondary router. I know the question stated a windows based option, but one of the comments the OP made was about purchasing a Mac.

The only part of the equation that we don't know is the range needed. If this bicycle group is close together, then they could use a big speaker (thus not needing any Apps). If the group is really far apart (out of sound range), then the setup would need a much better antenna to keep the group on the network; but even then I believe they will run into issues (based on some of the comments I just read on Airfoil).
torclausen (author)  canucksgirl5 years ago
I think we are heading toward using both a windows machine and a router to save money and to extend the range.
torclausen (author)  canucksgirl5 years ago
How would that work exactly? I would open up itunes on a phone, and broadcast with airplay... and all dozen other iphones would receive the signal? Is it carefully synced like airfoil is? I know that airfoil uses airplay...
torclausen (author)  canucksgirl5 years ago
wifi can be local, not internet.
torclausen (author)  frollard5 years ago
Frollard, you nailed it. This is not WAN, its LAN, and there isn't internet. The mobile computer and router travel together, and all of the iphones circle around within range, only on the local network..

Canuckgirl, Does it make sense that this audio software called airfoil does not require internet, only a local area network?

Jack, I will take all this into consideration, If there is noise in the inverter, I will switch to batteries. No worries there. I do wonder if airplay will have power noise in it. I kinda doubt it, as it never is analog (or at least thats how I understand it)

I am really needing help with the computer and the router. Does my plan make sense. Is it the best way to go? I also thought of buying a old mac mini and put a solid state drive in it.... but I think that will be more money.

tektig5 years ago
torclausen, sorry for not directly replying to your comment but not seeing a reply button. Yes, that router should be appropriate for your needs in fact it already sounds like a custom firmware was installed on it. The default passwords for the tomato firmware is some where in here

In that case getting in to that leaves you to configure your router and test things out. In case you where wondering chip set does matter when you flash that type of router. It's a long standing model and has had a long history of design.

Knowing which one you have might give you some insight to getting the most out of your hardware.

A few other thoughts I should have included in my last post.

* You might want to consider connecting your server to the router via Ethernet (maybe have it on the wan port but any should suffice) as opposed to wireless. Leave wireless exclusively to the clients
* You probably have potential for remote management using some device like a tablet or phone depending on how you have it connect to the server.

I'll try to respond to any additional questions you might have but can't say I'm always near a computer.