Looking at building an Access Point / Repeater and need some advice - Page 1
Forum section: electronics / projects

author: Pack34
author_rank: Frequent Contributor
timestamp: April 13, 2015, 03:08:27 am
content: I'm looking at designing an access point / repeater as a professional development project and I need some advice on how to get started with this.For the software bits, I'm looking at OpenWRT for the software base but I'm lost on the hardware to build everything on.https://openwrt.org/I'm guessing that there's no chance to program any of this in Visual Studio? I'm probably going to be forced to work with Eclipse. If anyone knows of a way to do this in Visual Studio I would appreciate the information. I remember Eclipse being a royal pain in college.For hardware development platforms, I found Doghunter on Qualcomm's vendor page but I'm concerned about the Arduino ones. I'm intending this to be a professional development project where I learn new technologies, tools, etc and I want to stay as far away from anything Arduino (or anything "uino") as humanly possible. The Chiwawa EVB looks promising, polished development board and no reference to Arduino to be seen.I'm more inclined to start off with one of these:https://developer.qualcomm.com/mobile-development/development-devices/internet-everything-ioe-wi-fi-development-platformOne thing I'm a bit cautious with, is that they are plastering IoE over everything. It makes me think that these are primarily for connecting a device to an existing wireless network (a "thing" that connects to the internet) and not acting as an actual access point / repeater.I'm finding that the Atheros chips do not seem to be listed on the typical players (Digikey, Mouser, etc.) I'm guessing that if I want to get a handful of these for development and training purposes I need to go through a vendor of some kind? Do I just hit up the contact form on Qualcomm's website? I want to take a stab on building the hardware after the firmware is sound.I know this may be a tall order for a single person ProDev project but I need some new challenges.

author: NiHaoMike
author_rank: Super Contributor
timestamp: April 13, 2015, 03:49:53 am
content: Start with one of the popular wireless routers. If you need more range, add one of those amplifier modules.

author: Smokey
author_rank: Super Contributor
timestamp: April 13, 2015, 04:01:02 am
content: The Buffalo hardware is specifically designed for ddwrt and is pretty cheap.http://www.buffalotech.com/products/wireless

author: smjcuk
author_rank: Frequent Contributor
timestamp: April 13, 2015, 09:46:26 am
content: Or just buy a Microtik Routerboard:http://routerboard.com/

author: Pack34
author_rank: Frequent Contributor
timestamp: April 13, 2015, 12:38:09 pm
content: Quote from: smjcuk on April 13, 2015, 09:46:26 amI'm familiar with Routerboards, but I also want to be able to physically build one. I'm doubting that I would be able to get a schematic from them or even a pinout of the Atheros chips.I was able to find a contact on Qualcomm to get some reference designs but it seems everything is behind an NDA wall, so I won't be able to share any of that information here.

author: smjcuk
author_rank: Frequent Contributor
timestamp: April 13, 2015, 01:50:19 pm
content: Qualcomm (and Broadcom) don't care about you unless you're shipping volume. I wouldn't start at that end either.Pick a vendor that ships ARM kit as the toolchain is pretty free and open for that (GCC), runs linux out of box (i.e. you don't have to boostrap a new system which is really complicated) and find a dev board with Mini PCI. Then get an Atheros Mini PCI WiFi card, slam it in, load the firmware, up pops your eth interface, build a kernel and initrd and off you go. You can then use various kernel ABI calls from C (warning: config is HARD) to configure the router, userland pppd for ATM/PPPoE support and dhcpd etc. That's probably easier than porting DD-WRT or something.That's about a year's worth of work above.When that works, then you can think about knocking out a PCB with all the non essential dev board stuff removed.Also you won't get anywhere with Visual Studio. You'll need to cross-compile on Linux. TBH it's a ton easier than dealing with Visual Studio as well when you get used to it. I deal with Visual Studio a lot and you don't want to go there for embedded.Big project there. I've seen people with 5 people on the team take two years to fail on this front before.

author: wemme
author_rank: Regular Contributor
timestamp: April 13, 2015, 09:54:51 pm
content: Hello,Realtek, Broadcom and Marvell won't even talk to you unless you are doing 200k-500k units/PA and even then they think they are doing you a favor.You may be better of just getting an Arm processor and a SDIO / usb wifi module and going that way.http://www.ccandc.com.tw/do good modules at a good price but if you go SDIO there are a mountain of WIFI modules available.if you just want to get something going why not just use a Raspberry pi and a usb wifi card? there is heaps of linux support (which openwrt is written on).Once you got a prototype together then go look at custom hardware at least then you have a handle on your requirements also.RegardsBart

author: Pack34
author_rank: Frequent Contributor
timestamp: April 14, 2015, 12:47:07 pm
content: Quote from: wemme on April 13, 2015, 09:54:51 pmBart,Thanks for the tips, but the Pi route is also I'm trying to avoid. At this point it's the SBC version of the Arduino that's closed source. I feel that if it's something I'm going to want to spin hardware on afterwards then I just don't feel that it's the first appropriate stepping off point.I would however be extremely interested in an ARM based development board with a mini PCIe connector (for the wifi module) and then shove OpenWRT on it. Polish up the firmware on that platform and then move to my own dedicated hardware. If anyone has one in mind they would recommend then I would be very appreciative if they could point me in the right direction.If I'm way over my head with this, then.... great. I'll fail and learn a hell of a lot along the way.

author: smjcuk
author_rank: Frequent Contributor
timestamp: April 14, 2015, 01:10:02 pm
content: These are a good baseline platform. They are 250MHz ARM9. That's probably all you need for a router.Product:https://www.embeddedarm.com/products/board-detail.php?product=TS-7552Wiki / manuals / schematics:http://wiki.embeddedarm.com/wiki/TS-7552Good luck

author: Pack34
author_rank: Frequent Contributor
timestamp: April 14, 2015, 02:36:25 pm
content: Quote from: smjcuk on April 14, 2015, 01:10:02 pmDude, that is awesome! I've been really wanted to mess with some practical applications of FPGAs as well. I noticed that a lot of the routerboards also have some Xilinx chips on board. I'm going to order one of these today.

author: smjcuk
author_rank: Frequent Contributor
timestamp: April 14, 2015, 02:53:33 pm
content: Just watch out when picking WiFi cards - some of them don't support AP functionality which means they're client only. Not sure about the ralink ones they ship with that.

author: wemme
author_rank: Regular Contributor
timestamp: April 14, 2015, 10:45:49 pm
content: Quote from: Pack34 on April 14, 2015, 12:47:07 pmAlmost sounds like you are reinventing the wheel? I must have missed something.Why do you need to use PCIe ?? PCIe requires a lot of care in layout.https://www.olimex.com/have a range of ARM modules including the allwinner.RegardsBart

author: Pack34
author_rank: Frequent Contributor
timestamp: April 15, 2015, 09:04:14 pm
content: Quote from: wemme on April 14, 2015, 10:45:49 pmIt's supposed to be a learning project. Reinventing the wheel is part of the game.I figured PCIe because the radio carrier boards I'm familiar with (Routerboards) all use them for modules. It's easy to swap them out and the PCIe cards are easy to come by. If there's another typical radio connector format that I should be paying attention to I'm all ears.