In this post I will be explaining some steps and decisions of the project so far. But remember, at the moment it’s far from a final device so keep coming back for updates ;)
Also, if you have any ideas and want to contribute, leave a comment!

Hardware

Choosing The Microcontroller

ATmega328 Chip

While there are tons of options regarding what kind of microcontroller and development board you want to use, we ended up on the almost clichéd Arduino or in this case a cheaper clone, RBBB, but still with the Arduino bootloader.
Please don’t start a comment flame war because you think there’s some better option.
The main reasons for using an Arduino “compatible” board are the vast amount of tutorials, libraries, code samples and examples, the fact that Processing is stupid easy ∴ fast to use, and did I mention it’s cheap.


After choosing the (lets call it) platform, there were some questions: How to safely lock and trigger a camera? How to detect lightning fast enough? How to power it? How to encase it? How to configure it?

Light Detection

One way to detect changes in light is to use a photoresistor, but are these fast enough to detect lighting?
Again, research. Obviously this project is not the first of it’s kind, so what solutions are out there.
Most photoresistors take too much time and they’ll miss the whole flash, so they are ruled out.

I stumbled upon just the thing, as well as some other really great ideas.

3.., 2.., 1.., SMILE!

With most DSLRs it’s really easy to control them with a wire. It usually just requires connecting ground either to focus or shutter.

The immediate thought was to use a transistor. Problem is, nobody wants to connect a +800€ camera to a ~10€ piece of DIY mayhem.
There are other ways of separating two circuits, like relays. But since relays are really, really slow when it comes to photographing lighting, it had to be ruled out.
After some more research, I found out a great alternative, opto-isolators (or optocouplers). They use a LED and photosensor (phototransistor for the really fast ones) to separate two circuits. Oh, and they are cheap, like really cheap.

Power!

The first idea was to use some kind of rechargeable batteries, like AA-sized NiMHs. But that wouldn’t be the most practical solution.
After thinking about the requirements, like that it needs to be rechargeable, relatively small, safe, provide 5 volts. Using a cheap emergency USB charger just seemed obvious. It has a built-in regulator that provides a clean 5 volts, it can be charged via USB, and has some nice battery status LEDs.
But would this cheap “2000 mAh” battery be enough to power a backlight LCD and the chip?
Only one way to find out! I knew that these ATMegas don’t really consume that much, but I wasn’t sure about the LCD and leaving it constantly refreshing.
I thought the battery would be enough to be used for about a day, but oh, was I wrong. Turns out, it lasts almost 30 hours.

User Interface

LCD117

16 x 2 Blue LCD and LCD117

Is the LCD really necessary or can it be configured some other way to configure it?
The first idea was to use potentiometers for thresholds, buttons for selection, but since the LCD with a controller isn’t that expensive, why not? And it only uses one pin on the microcontroller as it comes with the LCD117 serial board.

Buttons

Looks like a mess, but saved me a lot of soldering and space

A 5 button d-pad seems like enough. Up and down to control the menu, left and right for configuring settings and one button to select.

The common thing would be to use digital inputs for each button and de-bounce them. Pins are expensive so instead, I’m using one analog input and have a different resistor for each button. This way, I can read in the loop the current value of the input and see what button is being pressed.

This is what the mess looks like at the moment

Some devices are having problems showing up in the Android Market website, this is happening with rooted and non-rooted devices, updated and non updated ones.
If you only see a “There are no Android devices associated with this account.” follow these instructions.

First the obvious, you need a Gmail account (not Google Apps) to use Market and this has to be your primary account.
If you do have this and it’s still not working, these steps will work for rooted devices, if you don’t have a rooted device, you must restore factory settings.

1. Log out of web market
2. Kill running Market on your device (Settings->Applications->Manage applications->All->Market->Force stop and Clear cache)
3. Put your device to offline mode
4. Remove /data/system/accounts.db and /data/data/com.android.vending/shared_prefs/vending_preferences.xml (to be safe, just move them to /sdcard/)
5. To do this, the easiest way is to use adb, so run the following commands: adb remount; adb shell
6. And in the shell: mv /data/system/accounts.db /sdcard/
7. Then: mv /data/data/com.android.vending/shared_prefs/vending_preferences.xml /sdcard/
8. And: reboot
9. When your phone boots up, put it back to online and go to the Market, it will ask for you to sign in to your Google account (do this with a gmail account, not apps) and then to agree to the terms, do this and leave it in the “Loading…” screen and just wait
10. After a few minutes go to the Android Market website and log in
11. You should now see your device listed
12. Let me know in the comments how it turned out

Years ago I wrote  a tutorial about resetting a lost root password on most Linux distributions.
Simple stuff like giving boot parameters to Grub and Lilo, yet it became somewhat popular, and it’s still floating around many forums.

Well, people are still forgetting their passwords, so here’s a new “cross platform” tutorial and how-to on resetting your personal and root passwords.

This time it’s for GNU/Linux, Mac OS X and Windows.

Mac OS X

Lets start with the easiest one, Mac.
If you don’t have Firmware Password enabled, resetting your password is really easy, just follow the instructions on Apple’s support site. All you need is the installation disk.

I’m not going to rewrite those instructions since the ones provided by Apple are sufficient.
On the other hand, if for some reason those instructions fail or you don’t have an installation disk, all is not lost.

I Can’t Remember The Firmware Password

In most cases changing the amount of physical memory (RAM), will clear out the PRAM in your Mac, thus also clearing the Firmware Password.
There isn’t that much information on how the Open Firmware in Macs work, but this is a very simple hack that you could try.
If this doesn’t help, you’re going to need to access the hard drive outside of the machine.

I Don’t Have The Disk!

In this case you’re going to need to access the hard drive.
The easiest way to do this is just to boot up your Mac in single user mode by holding command-s, it’ll boot right on to the command line where you can remount your filesystem to get write permissions:

mount -uw /

And then you can either mess with the Open Directory files to reset your password, or easier, just remove the /var/db/.AppleSetupDone file to make the OS think it’s a new machine and give you the “first time boot wizard”. Command for this is:

rm /var/db/.AppleSetupDone

Afterwards just reboot the machine:

reboot

If these fail, one way would be to just boot either with some live Linux distribution that can mount the filesystem your OS is located in or take the hard drive out and mount it with some other machine.

Windows

There are many good tutorials on resetting Windows passwords, so I don’t think there’s a need for a new one (and to be honest, I don’t really care). But anyways, if you’re looking for great tools, here you go with my personal favorites:

• Ophcrack is a simple open source tool to crack LM and NTLM hashes.
• ntpasswd is a tool to reset your passwords and edit Windows registry.

Ubuntu

If you use a Linux distribution, have lost your password and don’t know how to reset it, you’re probably a Ubuntu user. Nothing bad, this is just the most likely scenario as more and more “human beings” have gotten tired of Windows.

There are some differences between current, future and old releases of Ubuntu, like how the recovery mode works and Grub. I’m going to focus on 8.04 LTS, 9.10 and have a look at what to expect in the future.

Until these very latest Ubuntu releases the security (if you’ve got physical access) hasn’t been that good, and that made resetting passwords really easy.
With these newer releases you can’t just boot up the machine to recovery and change the root password, if you’ve set one.

I haven’t set a root password

Most users simply use sudo to run commands that require root permissions, or they just use some GUI tools and never touch the command line.
If this is the case, you haven’t set the root password (or alternatively you’ve set it and remember it) and you’ve just forgotten your user account’s password, you are lucky.

Just select recovery mode on the Grub list (you may need to press ESC while Grub is loading).

After your machine boots you’ll be greeted with the recovery mode window, just select “Drop to root shell prompt”.

And now you can change either your root or user password.
“passwd” changes root’s password and “passwd toni” changes Toni’s.

After this there isn’t much to do but to reboot (just type “reboot” and hit enter, obviously).

But it’s asking my root password

As a safety feature in most distributions, you can’t go to the root shell (or run any commands via init) without giving your password.
To bypass this, you’ll need to access the partition where your /etc/shadow is located (assuming you’re using shadow passwords).

The easiest way to do this would be to boot up with a Ubuntu CD, mount the partition and find your shadow file and clear your hashed password there.
I’ll be writing more information about this later.

More?

Ideas, comments, better ways to do this, typos, etc.
Hit the comments and let me know!