Instructables
Picture of $3 MINI PROJECTOR
Hello! This time i am here with a small mini projector just out of $3 . This is a very fun project to make and pretty easy to make.You need to switch off the lights and watch the action! It is powered by a mobile phone or any digital media player.It's quality is very good if you will use a good phone with full brightness and high contrast. The better the brightness and contrast  is the  better is the projection. The mobile i've used here has very less features and my dad won't allow me to do this with his expensive phone so i have to use a bad one with bad quality , very less brightness and contrast but i assure you if will use a good bright  mobile phone with good brightness control you will get very good quality! I can't show you it's working image because i don't have a mobile with a bright screen and my camera is not catching that much low light but i assure you it's visible! I f you are not getting that quality tell me what problem you are having!
 
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Step 1: Technical details.

This projector works on the principle of magnification. The brighter the image from the source is the better is the quality of projection.The source should be held upside down or the projector box  should be upside down to get a correct image on the canvas.The room should be kept dark. The distance between the source(the mobile phone) and the lens should be adjusted  (Keeping the distance between lens and the canvas constant means)accordingly to get a non blurry image on the canvas. The words or the alphabets will be right side left.
orangeisnon12 days ago

I bought a cheap Google Cardboard kit and noticed this same thing happened, and thought, "what if I used a higher quality glass lens", and I see that that's exactly what you did.

It took me hours of time, a box shipped around the world, and a $600 phone to not come close to what you've done with $3. That's really impressive.

I'll be going to the thrift shop in the next few days to get some lenses (I have a bigger phone, so I'll probably need a bigger lens(?)), and I'll let you know how it goes!

I also had the idea to somehow pump more light into it, but I have no idea how I'd even do that. I'll work on it.

Thanks for the great guide, and the wonderful inspiration!

Sorry bud but i am the author i just forgot the password of my account so i made a new one!

Now yes if you have a $600 phone the make it to the highest brightness , take a wider lens and the magnification also depends on the ppi (pixel per inch or simply how high picture quality your screen can deliver! if you have other problem you may contact me on facebook or by mailing: samadhaque23@gmail.com or samadmaman haque on facebook!

rimar20001 year ago
What screen size you got in the wall?
samaddon (author)  rimar20001 year ago
It depends on what screen size you want ! But the max i have tried with my old phone it is around 25cm*20cm. If you will use a phone having high brightness and contrast !
This sounds pretty sweet! Do you have any images of it in action?
samaddon (author)  Penolopy Bulnick1 year ago
I have a problem with this because i don't have a good mobile phone to use and my parents are not going to buy a good one for me so i can't and if i use one of my old mobile phone it's not very bright so my camera is not catching that much low light on the wall so i think i need to win one phone but i don't know i will or not but i will try taking a picture i will give in two three days ! Sorry for you inconvenience! But i assure you i you will use your i phone it will project very good quality of image!