Here is a screenshot, notice the extra ‘Sensors’ link on the top right to access the info, the page does not require login

I had written a bunch of Lua code to read the serial communications coming from the ATMega168 microcontroller (it was sending its analog input values) and store it into files in /tmp which were then read by some more Lua code in the (awesome) LuCI framework to make those sensors all cool and AJAXy on the router’s web-admin menu. This worked great until the NTP attempt. So I wanted all this code back. So in case anyone is as foolish as I was to lose their code in the router, here are the steps I took to recover it. David Woodhouse (dwmw2) and dedekind at #mtd on irc.ipv6.oftc.net were extremely helpful with all this and pointed me in all the right directions.

1. backup the jffs2 image from the router using dd. mine was coming up in failsafe mode so i had to telnet into 192.168.1.1 and then run command `dd if=/dev/mtdblock2 | gzip -c | ssh nemik@pillbox ‘dd of=/tmp/mtd2.gz’ bs=2048` but make sure you do the right mtdblock2 device. do `cat /proc/mtd` and choose the one that is for “rootfs_data”. pillbox is a Linux box on my network I transferred this all to.
2. `gunzip /tmp/mtd2.gz` on the Linux box and i got my 5.5MB partition.
3. wget ftp://ftp.infradead.org/pub/mtd-utils/mtd-utils-1.2.0.tar.bz2. untar, make, make install
4. `sudo mknod /dev/mtd0 c 90 0`
5. `sudo modprobe mtdblock`
6. `sudo dd if=/tmp/mtd2 of=/dev/mtd0 bs=2048`
7. `sudo mount -t jffs2 mtd0 /tmp/1/` THIS DIDN’T WORK! (right away). The Fon router and openWRT are big-endian and I was trying to mount this on a little-endian x86 box. I needed to recompile the jffs2 kernel module to be big-endian. David Woodhouse (creator of JFFS2) writes how here: [http://www.infradead.org/pipermail/linux-mtd/2007-May/018227.html] I needed to get the kernel source and recompile the jffs2 module
8. get the kernel source `apt-get source linux-image-$(uname -r)`
9. go into the source and do `make prepare_modules`
10. copy /usr/src/linux-headers-2.6.27-14-generic/Module.symvers to the source. this will be different for you, but the Module.symvers is important otherwise the module won’t load properly
11. Change the native_endian #define in fs/jffs2/nodelist.h to be little_endian as David writes in the infraread link on step 7.
12. do `make CONFIG_MODVERSIONS=y M=fs/jffs2`
13. if it compiled correctly, you then have a jffs2.ko module. load it via `sudo insmod /home/nemik/code/jffs2/linux-2.6.27/fs/jffs2/jffs2.ko`
14. now try `sudo mount -t jffs2 /dev/mtdblock0 /tmp/1/` and it worked for me!

I was now able to see all my lost files in /tmp/1/ !!! the whole filesystem was there and worked great. I extracted all the code I wrote and learned my lesson never to do development on a router and always backup and check in. Hopefully this helps someone out.

So I thought it would be cool to automatically control all this via the Arduino. I built a simple little circuit to control the pump so it runs for a few seconds every 10 minutes. However this could be expanded further so that the entire hydroponics setup can be automated via a computer that talks serially to the Arduino.

The Firmata (http://firmata.org/) firmware is designed to let a host computer talk to the Arduino in this way. So I modified it a little to for the project. It can use the Firmata functions of reading analog pins to get sensor readings but I wanted to have critical functionality like the turning on/off of the pump at specific intervals to be under the Arduino’s control. Just in case the host computer crashes or a connection is lost somehow, that a critical part of the plant’s needs such as water does not break as well.

The project is hosted here http://github.com/nemik/arduinoponics and licensed freely under and MIT license.

There is still a lot of work to do here. I should post schematics for my setup first I suppose. So I’ll do that once I find a decent software in Mac or Linux that can draw schematics, never done this before.
Also, I need to write host-software for the setup. I have a FON2100 Linux modem running the OpenWRT firmware and it has the Lua language on it. I’ve never used it before but it doesn’t seem too hard. I’m thinking to maybe write a Firmata implementation for Lua (probably based on the existing Java one used in Processing). I already got it talking serial to the Arduino so it might not be too bad. Or I could just use an old laptop and then maybe modify some existing Firmata host software rather than have to make the Lua one; I’ll have to see. The Fon router is just attractive now because it comes in such a small size and runs off 5V so it could share the power for the Arduino. Provided the 12V adapter I’m using for the pump and 7805 regulator to the Arduino can handle all this…it’s only rated for 1A. I may have to get a larger one.

Anyway, let me know what you think. I would love suggestions for this.