Laptop touchpad-based LED lighting control


[Dave] needed some extra light above his desk/workbench area and decided to wire up some RGB LED light strips to brighten the place up a bit. He wasn’t content with using a standard switch to toggle them on and off, and after some brainstorming, he decided to build a capacitive touch circuit using a pair of copper tubes mounted in a project box. Just as he was putting the finishing touches on his switch, he saw a project online where a Synaptics touchpad was used in conjunction with an Arduino for lighting control. The copper tube switch was pitched, and he got busy working with his Arduino.

When connected to an Arduino, the touchpads can be used in two modes – relative and absolute. Relative mode is familiar to most people because it is used to guide the mouse cursor around on a laptop’s screen. Absolute mode however, relays coordinate information back to the Arduino, allowing the user to map specific areas of the pad to specific functions. [Dave] enabled his touchpad to use absolute mode, and mapped a handful of different functions on the Arduino. He can now fade his lights on and off or light the room on a timer, as well as use a sliding function to tweak the LEDs’ brightness.

It’s a neat, yet simple hack and a great way to repurpose old laptop touchpads.

Continue reading for a quick demo video he put together, and swing by his site if you want to take a look at the source code he used to get this working.

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Laptop BIOS password recovery using a simple dongle


In his line of work, Instructables user [Harrymatic] sees a lot of Toshiba laptops come across his desk, some of which are protected with a BIOS password. Typically, in order to make it past the BIOS lockout and get access to the computer,  he would have to open the laptop case and short the CMOS reset pins or pull the CMOS battery. The process is quite tedious, so he prefers to use a simpler method, a parallel loopback plug.

The plug itself is pretty easy to build. After soldering a handful of wires to the back of a standard male D-sub 25 connector in the arrangement shown in his tutorial, he was good to go. When a laptop is powered on with the plug inserted, the BIOS password is cleared, and the computer can be used as normal.

It should be said that he is only positive that this works with the specific Toshiba laptop models he lists in his writeup. It would be interesting to see this tried with other laptop brands to see if they respond in the same way.
Since no laptops are manufactured with parallel ports these days, do you have some tips or tricks for recovering laptop BIOS passwords? Be sure to share them with us in the comments.

Quick hack brings Wi-Fi to an aging laptop


[Jarrod] has an older Compaq laptop he is still pretty keen on, but he has one niggling problem – the laptop doesn’t have a built-in wireless card. He recently changed security protocols on his home wireless network to WPA and realized that his old Linksys PC card only supports WEP. He decided it was time to find another way to connect wirelessly, so he started searching around for options.

It turns out that his laptop does have the ability to accept a LCD-mounted add-on wireless card, but it costs about $100 and doesn’t support WPA. He figured that the card slipped into some sort of glorified USB port, and after disassembling the laptop, he found that he was right.

He quickly soldered a few wires and a USB adapter to the Bluetooth board that already occupied the card slot, then plugged in a wireless mouse to see what would happen. The mouse’s radio powered on without issue, and much to [Jarrod’s] delight, the port was USB 2.0 compatible.

Now that he knows the port is live, he plans on finding a small USB 802.11 G or N adapter to cram into the slot – with the deluge of miniature USB Wi-Fi adapters on the market, that shouldn’t be too hard.

V4Z80P: The 8-bit laptop

[Phil] over at Retroleum has cobbled together a clean, well put together laptop based entirely around a Zilog Z80 microprocessor and a pair of Spartan II FPGAs. These FPGAs allow him to reduce the number of devices on his board, and therefore cut his production cost as well as device size. He even managed to integrate a salvaged PSOne screen. The laptop comes complete with [Phil]‘s own Homebrew OS as well as a great graphical vector based demo.

Sure he’s updated the project in recent years to shrink the board, speeding up the Z80, and increasing the peripheral speed and functionality, but we’re suckers here for a total package hack. Seriously though, check out the newest version of the device as well as the backlog that shows the project growing over time.

Thanks to [Steth] for the heads up.

Swiveling arms replace Laptop LCD hinges

This swivel arm LCD screen is [Ben Heck's] latest hack. It replaces the hinges that normally only allow one point of rotation on the screen. You can still use the laptop like normal, but when space is at a premium a second adjustment, both in rotation and linear position, has been added using the slots and screw knobs seen above. Ostensibly this is to use on an airplane, where there may not be enough space to fully open your laptop. We’ll let you decide if it’s wise to try to get your own hacks past airport security. Historically, the TSA hasn’t been impressed with hardware hackers. We like how this came out and could see ourselves using these techniques to make a convertible tablet notebook by reworking the cable routing.

We’ve embedded [Ben's] quick demo of the finished product after the break. If you want to see the whole build process it is the subject of Episode 5 of the Ben Heck Show.

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BIOS password cracking

[Dogbert] took a look at the security that goes into BIOS passwords on many laptops. He starts off with a little background about how the systems work. People are bound to forget their passwords, so when you enter a wrong one three times in a row you get a message similar to the one above that locks you out until all power is removed from the system (then you get three more tries). But check out that five-digit number in the picture. That’s a checksum of the password. Some BIOS versions display it automatically, some require you to hold down a certain key during POST, but it’s the pivotal data needed to crack the password.

[Dogbert's] post doesn’t go into verbose detail about the algorithms he uses to brute force the passwords. But he has posted the Python scripts he uses to do so. Learning how to generate the passwords based on the checksum is as simple as studying the code, which is often the best way to learn.

Making a smaller keyboard

The keyboard on [Marek's] laptop stopped working. He didn’t want to buy a replacement so he decided to start using an external keyboard. But hauling around a full 104-key model is a bit of a pain so he decided to make himself a shorter keyboard. He basically chopped off the 10-key pad on the right side of the board. This had the unexpected consequence of removing the screws that hold the top and bottom of the case together so he ended up adding a few extra screws to shore it up. You may be wondering how the key matrix still works if a portion of it has been cut off. [Marek] used the simple trick of folding the extra part of the membrane over and covering the unused contacts with some tape.

If you try this you should consider getting rid of the directional arrows and editing keys as well. There must be a way to map those keys elsewhere. Perhaps the half-qwerty keyboard hack will give you some inspiration for that.