Pocket Projector Uses Raspberry Pi

June 6, 2018 by 51 Comments

Who doesn’t want a pocket protector projector? Nothing will impress a date more than being able to whip out a PowerPoint presentation of your latest trip to the comic book convention. The key to [MickMake] build is the $100 DLP2000EVM evaluation module from Texas Instruments. This is an inexpensive light engine, and perfect for rolling your own projector. You can see the result in the video below.

If you don’t need compactness, you could drive the module with any Rasberry Pi or even a regular computer. But to get that pocket form factor, a Pi Zero W fits the bill. A custom PCB from [MickMake] lets the board fit in with the DLP module in a very small form factor.

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Teardown: LED Bulb Yields Tiny UPS

April 23, 2018 by 90 Comments

Occasionally you run across a product that you just know is simply too good to be true. You might not know why, but you’ve got a hunch that what the bombastic phrasing on the package is telling you just doesn’t quite align with reality. That’s the feeling I got recently when I spotted the “LED intellibulb Battery Backup” bulb by Feit Electric. For around $12 USD at Home Depot, the box promises the purchaser will “Never be in the dark again”, and that the bulb will continue to work normally for up to 3.5 hours when the power is out. If I could repurpose that to make a tiny UPS for a microcontroller project of my own, it could be even more useful.

Now an LED light bulb with a battery in the base isn’t exactly rocket science, we can understand the product conceptually at a glance. But as they say, the devil is in the details. The box claims the bulb consumes 8.5 watts, but a battery with enough capacity to run such a load for 3.5 hours would be far too large to fit inside of a light bulb. Obviously there’s more to the story.

On the side of the box, in the smallest font used on the whole package, we get our clue. The bulb drops down to 200 lumens when in battery backup mode, or roughly as bright as a cheap LED flashlight. Now things are starting to come together. Without even opening the device, we can be fairly sure it will contain two separate arrays of LEDs: one low set for battery, and a brighter set to run when the bulb has AC power.

Still, I tend to be of the opinion that anything less than $20 or so is worth cracking open to see what makes it tick. Even if the product itself is underwhelming, there’s a chance the internal components could be useful or interesting. With that in mind, let’s see what’s inside a battery backup light bulb, and what we might be able to do with it.

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Laser Projector Ditches Galvanometer For Spinning Drum

April 20, 2018 by 25 Comments

Laser projectors like those popular in clubs or laser shows often use mirror galvanometers to reflect the laser and draw in 2D. Without galvos, and on a tight budget, [Vitaliy Mosesov] decided that instead of downgrading the quality, he would seek an entirely different solution: a spinning mirror drum.

He fires a laser at a rotating drum with twelve mirror faces, each at a different adjustable vertical angle. The laser will hit a higher or lower point on the projection surface depending on which mirror it’s reflecting off – this creates resolution in the Y direction.

Timing the pulsing of the laser so that it reflects off the mirror at a certain horizontal angle provides the X resolution.

As you can already tell, speed and timing is critical for this to work. So much so that [Vitaliy] decided he wanted to overclock his Arduino – from 16 MHz to 24.576 MHz. Since this changes the baud rate, an AVR ISP II was used for programming after the modification, and the ‘duino’s hardware serial initialization had to be hacked too.

For the laser itself, [Vitaliy] designed some nifty driver circuitry, which can respond quickly to the required >50 kHz modulation, supply high current, and filter out voltage transients on the power supply (semiconductor lasers have no protection from current spikes).

On the motor side of things, closed loop control is essential. A photo-interrupter was added to the drum for exact speed detection, as well as a differentiator to clean up the signal. Oh, and did we mention the motor is from a floppy disk drive?

We’ve actually seen builds like this before, including a dot-matrix version with multiple lasers and one made apparently out of Meccano and hot-glue that can project a Jolly Wrencher. But this build, with its multiple, adjustable mirrors, is a beauty.  Check it out in action below.

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Alexa Controls This Projector Thanks To ESP8266

January 27, 2018 by 7 Comments

[jfessard] doesn’t have extra-sensory perception, but does have an ESP8266. The little board seems to pop up in every hack these days. Inspired by not wanting to get up from the bean-bag chair or leave the electronics-housing cabinet wide open to use an HDMI switcher, [jfessard] hacked together an Alexa-compatible projector control via the ESP8266!

The core functionality here is the ability to turn the projector on and off, and to switch the HDMI source. [jfessard] connected the Panasonic PT-AE3000U projector to a Monoprice HDX-401TA 4×1 HDMI switcher. Tucked away in the cabinet below the projector, it is controlled using a IR LED transmitter breakout board sitting at the end of a fairly long set of jumper wire. The projector control itself is through a RS232 interface.

To make this easy to use with Amazon’s Alexa, [jfessard] turned to some libraries for the ESP8266 D1 Mini. The fauxmoesp library makes it look like a WeMo device, and the IRemoteESP8266 library made remote control code cloning a snap. One really frustrating part of this hack was the MAX232-style breakout board; getting a board to work when it’s labelled backwards takes a bit of head-scratching to figure out.

If the the projector ever gets too noisy, we suggest this hack that shushes the machine. For the moment, we’d rather take another look at this laser projector that mimics a cool ‘laser sky’ effect.

Teardown: What’s Inside A Christmas Laser Projector?

January 22, 2018 by 55 Comments

In the world of big-box retail, December 26th is a very special day. The Christmas music playing on the overhead speakers switches back to the family friendly Top 40, the store’s decorations get tossed in the compactor, and everything that’s even remotely related to the holiday is put on steep clearance. No more money to be made on the most commercialized of all holidays, so back to business as usual.

It’s in this narrow corridor of time, between the Great Holiday Unloading and the new spring products coming in, that you can find some fantastic deals on Christmas decorations. Not that long ago, this would hardly be exciting news for the readers of Hackaday. But Christmas lights and decorations have really started pushing the envelope in terms of technology: addressable RGB LED strands, Bluetooth controlled effects, and as of the last couple years, friggin’ lasers.

That’s right, you’ve seen them all over the neighborhood, probably took a few stray beams to the eye, you might even own your own. Laser projectors have been one of the most popular Christmas decorations for the last couple of years, and it’s not hard to see why. Just set the projector up in front of your house, and you’re done. No need to get on a ladder and string lights on the roof when you can just blast some directed energy up there instead.

Given how popular they are, I was surprised to see a lone Home Accents Holiday Multi-Color Light Projector on the clearance rack at Home Depot for around $14 a few days after Christmas. This was a 75% price reduction from normal MSRP, and right in that sweet impulse-buy price range. Let’s see what’s hiding inside!

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Not So Simple LED Upgrade For Microscope

January 14, 2018 by 18 Comments

[Amen] obtained a microscope whose light source was an incandescent bulb, but the light from it seemed awfully dim even at its brightest setting. Rather than hunt down a replacement, he decided to replace the bulb with a 1W LED mounted on a metal cylinder. The retrofit was successful, but there were numerous constraints on his work that complicated things. The original bulb and the LED replacement differed not just in shape and size, but also in electrical requirements. The bulb was also part of an assembly that used a two-pronged plug off to the side for power. In the end, [Amen] used 3D printing, a bit of metal work, and a bridge rectifier on some stripboard to successfully replace his microscope’s incandescent bulb assembly with an LED. He even used a lathe to make connector pins that mated properly with the microscope’s proprietary power connector, so that the LED unit could be a drop-in module.

Working on existing equipment always puts constraints on one’s work, usually due to space limitations, but sometimes also proprietary signals. For example, a common issue when refitting a projector with an LED is to discover that the projector expects a stock bulb, and refuses to boot up without one. Happily, the microscope didn’t care much about the bulb itself, and with the LED positioned in roughly the same position as the original bulb’s filament [Amen] obtained smooth and even lighting across the field of view with no changes made to the microscope itself.

Superconference Speakers Revealed

September 13, 2017 by 7 Comments

You’ll find the best hardware talks at the Hackaday Superconference. This year, we received over 140 proposals for a few dozen speaking slots. Although we’re still working through the proposals, today we can announce a few of the accepted and confirmed speakers so far. Below you’ll find about a third of the total slate of speakers.

Get Your Ticket to the Hackaday Superconference — they’re almost gone!

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