Night Billboard





Introduction: Night Billboard

Be seen! This will teach you how to make a giant sign that can be seen at night. We will be modifying an old-school overhead projector and using a large wall as the screen. The effect is amazingly professional looking, but the entire project cost only $30.

I built this to help a friend promote her company. Almost immediately after using the Night Billboard, she noticed an increase in business. I am planning on building another one that I will lease out to people wanting to advertise on it. In my town (NYC), even a small ad on a telephone booth can cost $20,000, so I expect that I should be able to make at least a couple grand a month leasing out space on this sign.

In any case, I've tried to be very specific about the parts I used and the necessary modifications. If you build a Night Billboard, feel free to post pictures here ... I'd love to see them!

Step 1: Obtain the Parts

You will need an overhead projector, and some light bulbs of type EVD - 36V, 400W.

For my overhead projector, I found a 3M 9800 series on eBay for $25 with shipping. I highly recommend this model as it has one of the highest lumen outputs making the image extremely bright. It is also designed to be user-serviceable from top to bottom, so if you ever have any problems, it's relatively easy to make the repairs yourself.

For the light bulbs, I googled around a bit and found the best deal on the EVD - 36V, 400W
here. I don't have any affiliation with this site, but I recommend them for low prices and speedy delivery.

Step 2: Install New Bulbs

First, unplug the projector and open the top cover. On every projector I've seen, there is a little button you have to push in on the side of the writing surface. Push this button in and the whole top cover (including the writing surface) will lift off.

You will see the light bulb chamber right in the middle. Lift the lens covering the light bulb chamber and remove whatever bulbs are in there. Remember, to get a bright enough light, we are going to replace the stock bulbs with our new ones.

Carefully insert the new bulbs where the old ones were. Do not touch the bulbs with your bare hands or you will shorten their lifespan. Usually the bulbs will come in some kind of packing material that can be used to help insert the new bulbs without touching them directly.

Close the cover to the bulb chamber, and you're all set.

Step 3: Set Voltage Jumpers

Now that we've installed the light bulbs, we need to set the voltage jumpers to an appropriate voltage for the new bulbs.

NOTE: if you are using a more modern projector, the voltage settings may be determined automatically and the jumper changes described here will not be necessary.

Locate the jumpers on the circuit board. You can see them highlighted in the image on this page.

The jumpers will be labeled. Put shunts on the STD jumper and the US jumper. If you are not located in the US, use the jumper that is appropriate to your country, but keep the STD jumper shunted.

Step 4: Design Your Graphic

Open your favorite image editor and create a new grayscale 8.5" x 11" image with 300 DPI resolution.

Make the background white, and mock up your text and graphics in black.

When you have everything set the way you want it, invert the colors in the image (Ctrl-I in Photoshop) and you should end up with white text and graphics on a black background. When this is printed, the light will shine through the "white" areas and the black areas will block the light.

Put this file on a CD and take it to your favorite printing shop. Ask them to print it on a transparency. The place where I had mine done charged me around $1 for each transparency.

Step 5: Turn It On!

Aim the projector at a blank wall, and turn it on. Line up the transparency so that your image shows up in an aesthetically appealing way, and then when you have it right, tape it down to the projector so it doesn't move around.

That's it - you're done! You now have a billboard for far less than anyone else in town paid for theirs.



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    I have the same idea except i would be using an LCD projector and displaying videos... such as commercials that i would sell for advertising space... I know it has been a while but did you ever encounter any legal issues with this and do you think it would make a difference that im playing full on commercials? I am in the bronx area so im hoping you would be the right person to ask.

    Hey, thats a great idea of using the overhead projector. I have used one for drawing big images on shirts with reflecting the image at the shirt.

    I looked for the bulbs in Germany but I doubt anyone sells them here. And you always talk about "bulbs". Do I need to buy just one ore more then one?

    Marco from Berlin

    I am interested in leasing out a space and I was wondering: 1-Where do you get the power on the street? (ohp do need a lot of power!) 2-Have you been successful in leasing the space out? 3-Any other thoughts legally (I live in Austin) Thanks!

    1 reply

    1) I live in the building upon which the projector sits. So I can easily run a wire up. I imagine you could use a generator if need-be. 2) Yes, but I will not go into details. 3) If you are worried about the legal issues, talk to a lawyer. Out of common courtesy, I made sure the light did not hit any windows or light up the wall outside of any windows. Really, as long as you are not a dick with the thing, I don't think anyone will care enough to put you in trouble. Like I said though, if you're worried about it, talk to a lawyer.

    I love this thing! How far will the projector project this image?

    1 reply

    I don't know. In mine, it's projecting over a distance of perhaps 40 feet. If you were in a sufficiently dark place, you could project over a greater distance. NYC is bright as shit at night, so I don't think a larger distance will work here. The problem is not just the light attenuation, but also the diffusion that comes from the projected image getting larger. In any case, you should give it a shot and let us know how it goes!

    Cool stuff. But why do you have to change the bulb? Wouldn't there already be a 36V, 400W bulb in there? And since the OH is set for those numbers, why do you need to change the voltage? Sorry if my questions are dumb, but I'm a newbie who's just got hold of a OH of 24V, 250W. Would anybody happen to know if it's possible to somehow upgrade it for 400W bulbs?

    2 replies

    Well, the higher the wattage, the brighter the image will be. I wanted a really bright and high-contrast image, so I used a brighter bulb. In order to do this, I had to monkey around with the jumpers as described. If you put a higher wattage bulb into a socket that cannot handle it, you might, depending on the safety features built into the projector, have a fire hazard. If I were you, I'd give it a shot with your 250W bulb first and see if the results are satisfactory. You may not be able to tell from the image I used, but the projection is around 50 feet high. To get something this large and have it still be bright, the higher wattage was required, but your project requirements are most likely different. When you do it, post your results - I'm sure we'd all love to see them!

    I still don't get why you need to change the voltage on the 3M 9800 which is already made for 36V 400W bulbs, like the ones you got. Or am I missing something?

    Sorry, can you explain step 3, as if you were explaining it to a small child? Just need some clairification on "shunt" and "jumper" to see if this is something I can undertake.

    1 reply

    It's a piece of cake. The jumper is a little piece of plastic that fits over two little prongs called a shunt. It can be removed with either fingernails or tweezers. If you have ever replaced a hard drive, chances are that you have changed a jumper or two.

    Here's a pic:

    See another implemented example of night billboards using common overhead projectors @ DIY Night Billboards DIY Night Billboards inspired from the work posted here.

    2 replies

    hey robertanton - nice job! just wondering ... what kind of life do you get out of your bulbs? it seems like i end up changing mine every few days.

    About 200 hours. That is the life of these lamps. 200 hours. Thanks again for the inspiration.

    I noticed that the projection is distorted, since you must tilt the projection lens up and the image isn't rectangular (similar distortions happen within view cameras--but you can compensate with swings and tilts in that case.) With normal cameras this type of distortion is called 'converging lines'--it's just happening in reverse...

    One way you might improve the image (without doing it optically):

    Compensate in the image editing program by dragging and widening the top of the ad--into sort of a 'keystone' shape. The subsequent projected image will distort in the opposite direction, giving you a rectangular picture. You can compensate for being off center, also, with a little calculation.

    PShop can do this for sure (select image, 'free transform', grab a corner with CTRL key and drag), and I assume GIMP can too.

    You can study the history of mathematic transformations of art by searching for anamorphic art.

    1 reply

    I meant widening the bottom, sorry. but you get the idea...

    Hey - thanks for all the positive comments! As for the legalities ... like I said, I talked to two lawyers before putting this up. Perhaps the laws in New York are more liberal towards this kind of thing? In any case, I believe you are correct about the possibility of being sued, and as you've pointed out, it can happen for pretty much anything. I'm thinking that if someone has a problem with it, their first step will be to send a letter asking me to take it down. If they do, I'll gladly take it down. I'm not trying to piss anyone off. You know, I actually anticipated this and when I make my next one (to lease out) I intend to charge by the day. That way if I have to take it down, I don't have an angry customer.

    I still think this is an absolutely amazing idea. I will have to show this to friends of mine that usually have events going on. This will definitely help advertise. :D

    That is a great idea. Good job and I hope you make lots of $$$. You may even be able to take that a few steps farther and build it smaller. Then you could make a smaller mount and be able to hide it better or mount it on a wall. What keeps some one from stealing it at the moment? Also I think there is a leagal issue here, becasue you are trying to promote a businees using someone elses property without consent. It could be viewed as defacment especially if it causes monetary losses to who everowns the building. It also depends on the laywer and the judges. How about this idea mount it in the bed of a pick up truck and park the truck on the street, then project it on the building. If you get hassled drive away and project on the next building. Mobile advertising. Cool idea.

    1 reply

    I agree. The legal issues are not as simple as acidus states.

    The law can apply other statutes (disorderly conduct, public nuisance, etc.) quite liberally on occasion (even if you would ultimately be exonerated.) Trespassing is certainly possible. Even trademark and intellectual property law comes into play (you are altering the appearance of the building which is trademarked as part of the public image of a company.) Libel, criminal or civil, might apply if the advertisement is counter to the businesses philosophy. The point of monetary losses is a very good one. Lawyers can be very creative if they are funded well.

    Even if is there is no criminal liability, there is probably civil. Even if you might eventually win. A law professor friend of mine once said --"you can sue anyone at any time over anything."

    Your best bet would be to license 'projection space' on the side of a warehouse or some other non-walk in building, hopefully near a highway.

    All that given--I wish you well. A very creative retargeting of technology.