Consistent contributor [Ken] has cooked up another contraption with his directional booklight. Combining an LED strip and privacy screen filter inside a wooden enclosure, this handy tool is made for someone who wants to read in bed without disturbing anyone else. The booklight sits on top of the page, the LEDs light up just the given area, and because the privacy screen only allows light to come straight off the page, only the reader can see any light and any other viewing angle is obscured.
[Ken] thought of everything. Rather than have the light stay on while the booklight is lifted to turn the page and possibly flash an unsuspecting slumberer, a tactile switch on the underside turns the light on only when it is pressed against the page, allowing very little light to escape.
Future upgrades include another switch on top to detect when the book is closed, and an accelerometer to detect when the reader may have fallen asleep.
We’ve reported a few of [Ken]’s projects before, like his 3D popup cards, unique weather display, and semi-real-life Mario Kart
Continue reading “Directional Booklight Invisible to Everyone But You”
We don’t all need super high quality electronic testing gear. Sometimes second-hand or inexpensive equipment is accurate enough to get the job done. Though it can be a bit annoying to miss out on some of those “luxury” features. [Ekriirke] had this problem with his cheap multimeter. He wished the LCD screen had a backlight for easier visibility, so rather than upgrade to a more expensive unit he just added one himself.
After opening up the multimeter [Ekriirke] found that it ran on a single 12V battery. He realized that the simplest thing to do would be to wire up four white LEDs in series. The four LEDs were arranged within the case off to each side of the LCD, one in each corner. The leads were bent at 90 degree angles and soldered together “dead bug” style. Thin strips of copper foil tape were attached to the PCB in such a way that the anode and cathode from the LEDs would make contact when the case was closed back up.
The tape wraps around to the other side of the PCB where there was more room for the next piece of the circuit. A capacitor, resistor, and transistor are used in conjunction with a momentary switch. This circuit allows [Ekriirke] to turn on the light for about ten seconds by pressing the button one time. The circuit also runs through the meter’s dial switch, preventing the LEDs from being turned on while the meter itself is turned off.
Want a back-lit keyboard? Make one yourself. Though you may not want to after seeing this build by [prodigydoo], who devoted 40 hours to upgrade his mechanical keyboard with a smattering of shiny.
No eye rolling just yet, though, because [prodigydoo’s] work is a monument to meticulous craftsmanship and dedication. So what if he accidentally dropped the keyboard’s PCB and cracked it? He patched that up with a few wires in true hacker-problem-solving fashion and no one will ever know.
With the electronics “safely” removed, [prodigydoo] set about desoldering every single key switch, then carefully detaching and disassembling the Cherry MX Blues. He then inserted an LED into each switch’s backplate, reassembled them, mounted the keys back on the board, then added some current-limiting resistors and heat shrink to the circuit. [prodigydoo] cut a few necessary holes for a power switch, state indicator LEDs (Caps Lock, etc.) and some under-the-board lighting, then rounded off the build by hooking up a power supply capable of running all the lights.
No microcontroller? No RGBLEDs? We like it anyway, and it seems [prodigydoo] is glad he kept it simple. Go check out the gallery for gritty details, an explanation of the circuit, and more pictures than your family vacation album.
[N8Mcnasty] is a HVAC tech who works on some big machines. One of his charges is a Carrier 19EX Chiller, rated at 1350 tons of cooling. 1 ton of cooling = 12,000 BTU. This particular chiller contained an odd LCD screen. It used a fiber optic bundle and a halogen light for backlight illumination. The system worked fine for over a decade. Now though, the halogen bulb has begun melting the glue on the fiber bundle, causing a dim display. The display in question shows some very important operating parameters, such as oil temperature, current draw, and process temperatures. Since they couldn’t easily see the display, the machine’s operators weren’t running the machine, placing stress on the other chillers in the building’s physical plant. [N8Mcnasty] tried repairing the bundle, however the glue kept melting.
A replacement display was no longer available, meaning that the entire chiller control system would have to be upgraded to a newer system. The new control system uses different sensors than the old one. This is where things start getting expensive. Replacing the sensors would also require draining the 15-20 gallons of oil, 4500 lbs of R134a refrigerant, and bringing the whole system down for almost two weeks, a $20,000 job. Rather than go this route, [N8Mcnasty] found an alternative. LED’s have come a long way since 1996, when the chiller was built. He simply replaced the halogen bulb with an LED and appropriate resistor. [N8Mcnasty] was even able to reuse the halogen bulb bracket. A bit of heat shrink tube later, and the fix looks like it was a factory option. He’s documented his fix here on reddit.
[nullpointr] wanted a backlit keyboard for his Asus Transformer Prime so that it would be a bit easier to use in low-light situations. He considered a few different options and ended up adding electroluminescent panels behind the keys.
Those paying close attention might wonder why we called this a laptop in the title. Well, it’s a tablet with a keyboard dock and that’s a mouthful. This actually really helps to simplify the modifications because the motherboard and other bits are all in the screen portion of the device. EL panels are also a nice choice because you can cut them to size and they still function. With a bit of case work, three panels were made to fit side-by-side.
The part that just isn’t going to make it in the original enclosure is the inverter that drives the panels. It’s the black box to the left. [nullpointr] added a USB-form-factor jack to the side of the case that allows the inverter to be disconnected quite easily. This way the Transformer Prime can still go with him on the road, it just won’t light up unless he also hauls around that add-on.
Way way back we saw someone do this with fiber optics and an LED. Unfortunately that project link seems to be dead so we figure it’s about time someone revisited the concept.
As the title says, [José Faria] added the ability to adjust his keyboard backlight based on ambient light levels. But that’s just one of the things he did during his hacking extravaganza with this Razer BlackWidow Ultimate.
When he first received the peripheral he didn’t like the blue LEDs used as backlights. So he removed all of them and put in white ones. He doesn’t talk too much about that but we’d image it was a ton of work. The new color was pleasing, but then the ability to adjust their brightness started to irritate him. There are four predefined levels and that’s all you get. Even the GUI which has a slider for adjustment couldn’t go outside of those levels.
His solution was to augment the controller with his own. He patched in an AVR chip to the transistor which controls the low side of the LED circuits. While at it he also noticed that the keyboard case was actually translucent. This let him hide a photosensor inside which automatically adjusts the light levels. But he did it in a way that still allows him to use the original functionality with the flip of a switch. See for yourself after the break.
Continue reading “Auto dimmer hacked into keyboard backlight”
[Lee Davison] acquired an Acer laptop that didn’t have a display anymore. He had enough parts on hand to add in an LCD panel and give it a CCFL backlight. But when he started looking for an inverter to drive the backlight he couldn’t find one. What he did have on hand were some smashed screens that had LED backlights and so the CCFL to LED backlight conversion project was born.
He tore into the LED display and found the driver board. Unfortunately he didn’t locate the datasheet for the exact LED driver, but he found one that was similar and was able to trace out the support circuitry on the PCB. This let him cut away the unneeded parts of the board without damaging the driver. He didn’t want to pull out the CCFL tubes until he was sure the LED conversion would work so he tried it out on another smashed panel (where does he come up with all these parts) and it worked great. Once he got everything in place he was very happy with the results. The only drawback to the system is that he doesn’t have the ability to dim the backlight.