Auto-sleep Hacked in PC Speakers

We can commiserate with [HardwareCoder] who would rather not leave his PC speakers on all the time. The Creative T20 set that he uses turn off when you turn the volume knob all the way down until it clicks. So shutting them off means repositioning the volume each time they’re switched on again. This hack kills two birds with one stone by turning on and off automatically without touching that knob.

The system is based around an ATtiny45 and a few other simple components. It uses two ADCs to monitor the rear input channels of the PC speakers. If no sound is detected for more than one minute, the shutdown pin of the speakers’ amp chip is triggered. That’s not quite where the hack ends. We mentioned it monitors the rear input of the speakers, but it doesn’t monitor the front AUX input. An additional push button is used to disable the auto-sleep when using this front input. There is also a fancy PWM-based heartbeat on an LED when the speakers are sleeping.

[HardwareCoder] was worried that we wouldn’t be interested in this since it’s quite similar to a hack we ran a few years ago. We hope you’ll agree it’s worth another look. He also warned us that the demo video was boring. We watched it all anyway and can confirm that there’s not much action there but we embedded it below anyway.

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Controlling real world objects from your lucid dream for $15

[Kyle Fredericks] tipped us about his first electronics project, a cheap and smart sleep mask that uses a vibration sensor to detect rapid eye movements.

As some of you may know, REM sleep is the part where you dream the most vividly and actively. If some external stimulation (sound, movement) is sent to you at this moment, it may help you take control of your dream by becoming aware of it. If not, your brain will create dream scenarios that incorporate this stimulus.

The interesting part of the concept is that the vibration sensor calibrates itself at the stage 2 sleep, when no eye movement occurs. This later allows a very accurate detection of the REM sleep stage, triggering a shelf stereo. Secondary buttons are even included in the mask sides.

[Kyle Fredericks] went to great lengths to document every step of the project, making it a perfect first step to learn electronics for beginners out there.

Decades old TV gets sleep function thanks to 7400 family of chips

[Viktor] dredged up a hack he pulled off years ago. His grandfather likes to end the day in front of the TV, but he falls asleep soon after sitting down. Rather than tick away the electricity meter all night, [Viktor] built an automatic shutoff which is akin to a modern TV’s sleep feature.

At the time microcontrollers were not as easy to source as they are now. So [Viktor] used a circuit based on the 7400 family of logic chips. It uses a multivibrator to feed some binary counter chips. These are used to divide the oscillations to establish the desired timing. He tuned the system to be about 15 minutes, but that can be adjusted using a potentiometer built into the multivibrator. When time is about the run out an LED next to the TV comes on. This way if [Viktor’s] grandfather is still awake he can press a button next to his chair to reset the counter. But if he’s already snoozing the counter will eventually switch off the television.

A desktop binary clock

This is the desktop binary clock which [Tim the Floating Wombat] recently finished building. He calls it the Obfuscating Chronoscope since it’s a bit more difficult to read than your traditional analog or digital timepieces. But the simple design looks neat and it’s a great way to learn about board layout and microcontroller code.

He started by solving a few questions about the display technique. He wanted to use as few LEDs as possible. He settled on just four, and to prevent unnecessary confusion, decided to make sure each type of display (seconds, minutes, hours) would have at least one LED on at a time. Hours are easy enough to display, but with just four bits how can minutes be shown? He uses a 5-minute resolution, always rounding up to the next division of five. This way the first bit will be illuminated on the hour.

A PIC 24F16KA102 microcontroller keeps time using its built-in RTC and a clock crystal. It puts itself into deep sleep mode after displaying the time. The black knob at the bottom is a push-button which resets the chip, waking it up just long enough show the time once again.

Lucid dreaming mask marries economy with comfort

Here’s an effort to make a cheap lucid dreaming mask that is also comfortable. The idea is in response to the goggles we saw in April (which would not be too comfortable to sleep in) and the wildly successful Remee (which has an $80 target price).

The mask itself is sewn from a child’s fleece blanket. Inside is a piece of foam cut from some recreation mat. You know, those squares made for a play area that connect together like a jigsaw puzzle. You may have already spotted the Arduino in the image above, but the project is designed to run from an AVR chip embedded in the foam. The design only uses three LEDs, which may or may not work for you — we’d guess it depends on how they line up with your eyes. The video after the break does a great job of illustrating each point in the construction.

If you’re looking for something less soothing and more recreational you could always try out these trippy goggles.

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Motion activated monitor wakeup

This hardware is used to keep a computer monitor awake when there is motion in the room. The monitor displays important information for firefighter in the vehicle bay, but only needs to be on when they are getting ready to go out on a call. The solution is a simple one, a PIR sensor combines with a mouse for motion sensitive input. When the PIR sensor detects motion it causes a mouse button click via a 2N3904 transistor. Now the monitor will not waste power or have burn-in over the long term, but whenever someone is in the room it will be displaying the information that the emergency workers need to know.

[Thanks Andy]

Grinding down your computer to just 8.5 watts

What can you do to make sure your system is running as efficiently as possible? Take a page out of [Mux’s] book, who went to great lengths to measure and adjust his system for ultimate efficiency (translated). What he ended up with is 8.5 Watts of consumption at idle and about 50 Watts under load. Luckily he posted a six-part series with all of the details.

Some of the changes he made were in software, like reducing voltage to certain hardware by adjusting BIOS settings, and installing display drivers that put the screen into the proper sleep mode. Others were hardware changes like swapping out the power supply with a hacked PicoPSU and removing unnecessary parts from the motherboard like the MAX232 com-port chip. Looks like we need to audit our always-on MythTV box and see if we can apply any of these power-saving techniques.

[Thanks Gijs]