I bought a portable 9000mAh battery pack – which gives out 5 to 5.5v at 2200 mA. Why? Well the intention here is to power something which doesn’t take much, well, to power, for a very long time. This is where the MR3020 steps in.
By default its intention as a device is to share, over 2.4Ghz WiFi (I think, I’m not sure if it does 5Ghz, I haven’t checked, but it does do 802.11bgn) a 3g or 3.5g mobile connection (from USB). It can also share this over your standard LAN Ethernet, or it can share the Ethernet over the WiFi.. I think you get the idea?
Well there’s this firmware called OpenWRT which lets me do what I want with it, effectively turning it into a small, linux-esque computer with its Atheros processor at the core.
So my intention is to plug in a GPS adapter, USB storage pen-drive, configure the device over Ethernet and use that 9000mAh battery pack to power it. I didn’t mention? The MR3020 is powered by a mini-usb port. Wonderful.
However, this project hasn’t been without, shall we say, trouble. You see, when you flash a firmware (its Operating System, like Windows or Linux) to the device it is then restricted to those files and programs in that firmware (short of some configuration files) and to expand upon it further you need to to install them. This can be done through ‘opkg’ which is OpenWRT’s package manager.
Unfortunately you’ve just used up the majority of the space on the device flashing the firmware, so if you’re fortunate you can add the packages to allow you to use a USB storage pendrive. If not, it’s time to make your own tasty good make feel nice firmware.
Which is what I tried to do. This did not go well. This is because the core of the firmware, at the base of it all is the kernel which interfaces between the software and the hardware. I had foolishly filled it with too much and it couldn’t load it. I had effectively ‘bricked‘ my mini router. That is to say, it no longer functioned as it should and it was stuck in a loop, rebooting.
A bit of soldering, the assistance of Nav from the Leeds Hackspace lending me a serial cable later, I was back on track with a working device. What I had to do, was transfer a new firmware to the device, using only the bootloader and TFTP (over Ethernet). This worked, to a point that I could now get into the failsafe mode of OpenWRT rather than just the bootloader. Where I then, more easily, transferred a better, larger, firmware to it and ensured that the configurations were reset to default.
Now I’m going to try building a firmware again, or maybe I’ll find one suitable and upgrade it. I had looked at PirateBox but that was mainly for sharing files, and MiniPwner – but the problems encountered with that (MiniPwner) are (by default) its kernel is out of date for the latest packages (easily fixed, I found, by using an upgrade firmware from OpenWRT) and a bit more tinkering to get it just right.
So back to trying to get the USB pen-drive and GPS to work at the same time (hacking in a USB hub) along with relocating the packages to the USB pen-drive.
Then, hopefully, I can do what I planned to. Triangulate and map WiFi access points on a Google Maps style layout referenced to GPS layout. Or something similar, maybe I’ll introduce BlueTooth or anything else I can pick up with a sensor. Yes, I might just be able to attach in a Minimus32.Comments Off on OpenWRT on an MR3020 – ish