Epson emp-s4 Projector LED Mod

Recently during one of my Ebay window shopping sessions I came across a listing for an 'as is' Epson projector missing a lamp. It was sold as is because it would turn on and then simply flash a lamp error and since the lamp is much more expensive than the projector as a whole, the seller undoubtedly decided to sell just the projector rather than purchase a new bulb. The best part was that he was willing to part with it for $25 with free shipping. As far as I could tell nothing else was wrong with the projector so I took the plunge.

While waiting for it to ship I read up on the control systems that these projectors use in order to control the ballast and lamp assembly. It looked like nothing more complicated than tricking an input to the main board to make the projector think a real lamp was inserted while in reality I would use a high power LED but more on that later. 

A week later it arrived in a huge box and as I hurried back to my dorm room I tore it open in excitement. It has three lcds, one for red, blue, and green. These three images are added together with the help of a lens to create the final image. The next step was to remove the ballast and figure out how which two wires from its control cable sent the lamp ok indication. I noticed that the ballast (the circuit board on the bottom left in the picture below), had a digital control circuit mounted vertically with three optoisolators near the i/o cable. These chips are necessary to insure that the digital low voltage i/o dont mix with the high voltages present in the rest of the ballast or else this projector might release its magic smoke. In addition two of the optos were facing left while only one was facing right. This hinted to me that the one lone opto was the output sent to the main board pictured in the upper right below to tell it that the lamp was operating perfectly fine so that the projector would stay on instead of shutting off and giving an error like it would without a lamp inserted.

So my solution was to short out the two wires that led to this opto (found with the help of my multimeter). I also needed to tape down the lamp door safety open switch so it could operate with the cover off. Now when I shone a flashlight into the lens input on the upper left of the image above I could faintly see an image being projected from the projection lens on the bottom right. Bingo, now I was getting somewhere. Now I needed more POWER!

I had bought a 30W 2000 lumen LED and 2A ac/dc driver in anticipation of this exact purpose a while ago so I dug that out of my parts bin along with some optical lenses to focus the light. I drilled into an old pentium cpu heatsink and attached it to the LED because after a few seconds it got rather hot. The fan came with the heatsink so I just wired it up in parallel with the exhaust fan seen below to the upper right of the picture. Then I used some framing wire to attached the glass lens to the assembly. This ensures that the light is concentrated and evenly dispersed into the small window to the left.

 Next I need a way to turn on and off the led because having the light on all the time when the projector was plugged in was no fun. I could have gotten fancy and dug into the buck control circuitry of my LED driver and done it that way but I opted for a more universal approach in case I wanted to upgrade the light source in the future. I patched a ac cable into the power input of the projector's main power supply board to gain access to 120V AC. Then I used a beefy relay pulled from an old computer battery backed ups (uninterpretable power supply). This small beast could handle 5A at 125V so it should be sufficient for the task. I placed out of the way it in a crevice in the bottom left of the projector as seen in the picture below. Normally when the coil is unenergized it opens the circuit so the LED is off. When it receives the signal from one of the other optos (I carefully tested with the projector open to see which control line to the ballast changed when the projector was turned on and off) it sends current through the relay switching the AC voltage into the LED driver thus turning the LED on. This way the hacked on LED would behave exactly like the original lamp: it turns on and off with the projector with no user intervention.

The LED driver in the protective plastic shield on top of the main power supply can be seen above in addition to the small optoisolator and flyback diode circuit I built to handle automatic relay control to allow the projector to turn on and off the LED itself.

I pulled ground and +12V for the relay coil from these two spots on the main board.

Finally a picture of the entire device fully modded to my liking. Its a thing of beauty.

Now for a test I played some video games on it for an hour and measured the internal temperatures to make sure that it would be fine. Here is a projected screen size of about 30" in pitch black room for your enjoyment.

And what game did I test I hear you ask. Only one of my favorites of all time ;-)

These images were about 30-35" diagonal. Not too bad. They look better in person its just that I had to use my phone cameras as I forgot to bring home my nice Sony camera for spring break. I can push the image to 45-50" and still be viewable in a pitch dark room but brightness degrades quickly. I'll see if I can get my hands on a 8000 lumen 100W LED and make this almost as bright as it originally would be with the stock lamp. Here is a quick video of the internals and it operating for those who are interested.

For now I will go ahead and call this hack a success. Now let me get back to beating Castlevania Symphony of the Night for the millionth time ...

If you have any questions feel free to comment below and I will do what I can to help.

Yet Another POV Clock Project!

Yep. I'm at it again. Yet another POV display (my third iteration in fact). I'm a sucker for things that move and blink rapidly. You can see my past POV projects in the Projects tab above.

This time instead of using a rotating disc or arm like I've done in the past I've opted to use a wand that oscillates back and forth to write out the image. I got the idea after seeing a commercial clock that uses the same mechanism. But you know it's no fun buying something ........ you have to make it to fully enjoy it!

So I stated off by testing out several methods to generate the oscillations. I took apart several harddrives to harvest the armature coils and magnets only to find that they couldn't bear the load of a long wand and still oscillate quick enough and with large enough magnitude to be useful. So I dug into my junk bin to see if I could find an idea.

I found a stiff yet springy piece of metal, a 'U' shaped plastic cut from a DIP tube, some coils from the brushless spindle motor in an old VCR I took apart ages ago, and two neodymium magnets from an old name tag. These would be the main components that would make up the armature and electromagnetic assembly. The springy metal is secured to the end of the plastic tube and the magnets are fitted on either side of the tube an inch or two above the metal. It looks something like this:

The leds are soldered to a little piece of perfboard and connected down the length of the tube with magnet wire. Here is a few pics of mechanism and leds working:

Warning!!! Physics lecture incoming: so here is the general concept of how the mechanism works. The springy metal is secured to the base, and the coils are mounted on either side of the two magnets on the arm. A microcontroller with an adjustable oscillator drives a transistor which switches the coils which are wired in parallel. This kicks the magnets and the armature every once and a while inserting kinetic energy into the system (it's essentially a forcing function and a mass spring system which can be described by a simple differential equation). By tuning the rate of the driving electromagnetic pulse to the resonant frequency of the spring and mass armature you can get it to sustain a large amplitude oscillation. I knew Physics would come in handy one day!

So, now I have a reliable oscillating mechanism as seen in this video:

And I have managed to get the leds all wired and working with a simple demo going:

So all I need to do now is add a photointurrupter to sense when the arm is at the starting position so that I can sync up the display and then code software for a character set and animations as well as add a real time clock chip. Oh and finish the case and solder the circuit. Don't worry I'll keep you all updated in the next upcoming steps for this project and I'm planning on releasing all of the code and schematics just because you guys are awesome. Stay tuned for the next thrilling installment of POV Clock!

UPDATE!!! I've used the electromagnetic pulse controller's led output as a sync signal to varying degree to display the ceremonious "HELLO" message as a first text demo as seen below.

Note that I am seeing some problems with the low refresh rate manifesting itself as an annoying flickering. I'll have to think something up to fix this problem. Until then!

TeardownTube - episode 14 - Nintendo DS

Here's the 14th episode of TeardownTube. Subscribe, comment, and like if you want to see a different device dismantled every week. The videos are not detailed instructions for repair but rather just for entertainment. Enjoy.

In this episode I explore inside a vintage 2004 Nintendo DS, the first in the line of the current gen dual screen portable game consoles. How did Nintendo manage to squeeze two 3" LCDs into your pocket? Find out in the video above.

Link: TeardownTube - episode 14 - Nintendo DS

TeardownTube - episode 13 - PSP Go

Here's the 13th episode of TeardownTube. Subscribe, comment, and like if you want to see a different device dismantled every week. The videos are not detailed instructions for repair but rather just for entertainment. Enjoy.

In this episode I tear into a sexy PSP Go I managed to score "broken" on Ebay for only $30. A stupidly easy fix. How did Sony manage to fit all of the goodness (well except for the UMD drive) of the psp down into the miniscule PSP Go? Find out as I explore and delve headfirst and have a "Go" at the PSP Go ... see what I did there?!!

Link: TeardownTube - episode 13 - PSP Go

Wanna read my repair experience for this device? Read the writeup HERE!

Broken PSP Go repair

I was crawling around Ebay about two weeks ago looking for good deals on broken but repairable electronics like I normally do. I've bought up countless iPods in the past to repair and resell. In fact just over Thanksgiving break I found a Nintendo DS that works perfectly but has a broken hinge for $5, but that is a story for another day. So begins a tale of an adventure on my most recent excursion.

This time I found a PSP Go (the full sized PSP's little digital media only cousin) that was listed by the seller, who was a reseller likely with no specialized knowledge about hardware, as "not turning on" and "unable to test without a charger". The description and the price ($30) piqued my interest. The photos posted showed that the unit was in good physical condition (with the exception of some scratches on the lcd). I wagered on the unit not having any water or electrical damage. It takes some experience and intuition to be able to tell what is repairable and what is too far gone. I just felt it in my gut that this would all work out in the end. So I took a gamble and quickly bought the device. I just hoped I hadn't thrown $30 away on a expensive paper weight. After all that has happened in the past.

It just arrived today and I excitedly returned with the small package to my dorm room to begin operation. I was so excited that I slammed my knee into my desk twice and winced in pain as I attempted to diagnose the device. Just as the seller said the device did absolutely squat when the power switch was pressed. No surprises there!

So I opened her up. Thanks Sony for using standard Phillips screws! If only they wouldn't use proprietary hardware ... but I digress. I was inside in under a minute. The only thing that was keeping me from the battery was an annoying warranty void sticker. Hah like I care. RIPPPPP! Well there goes the likely long gone warranty. I measured the voltage on the lithium ion battery and unsurprisingly it was completely dead. Oh well. Like the seller I didn't have the charging cable ... cough cough .. proprietary hardware ... so I was seemingly out of luck.

But I'm an engineer and engineers are stubborn but more importantly they are resourceful. I had a familiar max1555 (lithium ion/polymer battery charge controller) wired up on a breadboard. Of course another problem popped up, the battery used an annoying tiny connector but all was not lost. I'm up at college so all I had was some twisty ties so I cut off the insulation and just poked the wires into the connector, dirty and ugly but it'll work. Now I just needed 5-8V preferably without sacrificing a USB cable or power cord. I had a USB to USART bridge module on hand and luckily it has a 5V output so I just tapped into that. I plugged it into a USB wallwart and waited for the battery to charge a bit. I hooked up a meter to keep an eye on the battery's voltage.

Well after the battery sat there for a while I grew impatient so I measured the battery to make sure it had some charge and threw it back into the device. I waited with bated breath as I flipped the power switch ... big fat NOTHING!!! Of course it wouldn't be that simple. Oh well ... save me Google! A few minutes of research netted me with the hint that holding left on the D-pad while pressing power may yet resurrect my unit. I had nothing to lose so tried it ...

... and the PSP rose from its slumber to greet me with the XMB. Yeah. Now we are cooking. I thoroughly tested the unit and everything works. I ended up getting a device which used goes for around $80-100 online for only $30. All I needed was some patience, perseverence, and a huge pair of ... engineering skills!

Every device I fix or take apart gives me experience and knowledge. I highly recommend going to thrift stores or surfing Ebay and picking up cheap old electronics to mess around with. There is no guarantee that everything will work out as well this experience, but the skills I have gained from not just my successes but also my failures work to further my capabilities as well as my confidence. Every little lesson is invaluable.

Sorry I rambled on for a bit, but I just felt like trying to inspire other fellow engineers just starting out to take the plunge and mess around with some otherwise "broken" electronics and possibly save them from ending up in a landfill. Engineering and life are about being fearless and resourceful when conditions are not optimal. In the end I will be happy if my writeup was marginally entertaining and inspired others to do something similar.

As always comment below if you have any questions or are in need of advice. I always try my best to help. See you at my next electronics hacking or repair escapade!

TeardownTube - episode 12 - External DVD Burner Drive

Here's the 12th episode of TeardownTube. Subscribe, comment, and like if you want to see a different device dismantled every week. The videos are not detailed instructions for repair but rather just for entertainment. Enjoy.

In this episode I take a peek at the inner construction of a standard laptop DVD burner drive inside of a usb to pata enclosure. How do they make these small enough to fit into the slimmest of laptops? Find out now.

Link: TeardownTube - episode 12 - External DVD Burner Drive

TeardownTube - episode 11 - Western Digital Passport External Drives

Here's the 11th episode of TeardownTube. Subscribe, comment, and like if you want to see a different device dismantled every week. The videos are not detailed instructions for repair but rather just for entertainment. Enjoy.

In this episode I look inside two of my Western Digital Passport series drives. Is WD pulling a fast one on consumers? How did they manage to make the usb 3.0 drives even smaller than their older usb 2.0 variants? Watch to find out.

Link: TeardownTube - episode 11 - Western Digital Passport External Drives