Picture of Mini TV / Oscilloscope
Hi, I'm going to show you how to make a tiny TV/Oscilloscope. You will be working with a Cathode Ray tube which requires high volts and high pressure vacuums, so be careful. To build this you need patience.

Please rate my instructable or leave questions. They will be answered.

This is an old instructable I accidentally deleted a while ago and managed to find via a link deep in the interwebs. The TV has since been lost, but I plan on making a new and better one.

Step 1: Get All The Stuff

You will need...

+ A soldering Iron/Gun*
+ Solder*
+ A small phillips screwdriver*
+ A Hot Melt glue gun
+ Hot Melt Glue
+ Scissors

Electronic Items:
+ 3 DPDT switches*
+ Reasonably thin wire*
+ Two nine-volt battery snaps*
+ A Relay*
+ An LM386 audio amplifier IC*
+ A 100k Potentiometer*
+ A 10uf Capacitor*
+ A Small Speaker*
+ Female AV Jacks°

Other Items:
+ An old video camera {circa 1990}
+ A craft box to build it in

*can be bought at radioshack etc.
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Electrospark11 months ago


I just made one and it work's pretty well! :)

Thanks for the information!

I like this.

I never thought of that as a source of a cathode tub.

Have you seen my Instructable, Building a Digital Oscilloscope from a DIY Kit?

aaronXtreme3 years ago
this rocks
spystealth13 years ago
Wow! I'm pretty sure I found an old video camera just like that in a thrift store.
bmarshall-24 years ago
100k pot for the gain adjust on your LM386, are you sure?! do you mean 1k?
kikazz4 years ago
I apologize for my rudeness... I should have been a little more thoughtful with my remarks. and hey, im starting to spell bad too. Sorry.
grenadier (author)  kikazz4 years ago
No problem, I used to use IE back then. IE had and still does not have a spellcheck.
kikazz5 years ago
pleeeeeeeeeeease learn to spell. it really is annoying. thanks
El Mano kikazz5 years ago
Forgive me, but part of spelling is capitalization. Good job with the punctuation, though.

It's so funny when people post indecipherable garbage. It really reflects their personality.
12V5 years ago
i took apart a camcorder and found a crt with a 16mm screen and 6 pin base + a psu (2,200v) as well.
for brightness try adjusting the trimpots
e.g. those blue things with a screwdriver.
12V 12V5 years ago
try putting a 4.7-10 uf cap on the output of regulator  (mightprevent/reduce picture shrinkage)
luudvig5 years ago
uskmrules5 years ago
 hey can u take a picture of the board where ur power wires and video wires connect to the tv board. i cant find the wires.
okura5 years ago
Unbelievable.....a KID of 13yrs has SO much electronic savvy, so much vocabulary, so many tricks???? ...have seen many child prodigies and have mentored some myself, but this guy beats them all !! Either he's a miracle or a well planned hoax. Wish it isn't the later though...... I wish him good luck and Gods very best!!!! PS: wish there are ( I'm sure there are ) more kids like him around, too!
latobada8 years ago
i think the fact that because you don't want to take pictures, just takes the instructable down on so many levels. i mean it is quite original, and heck, i probably wouldn't be able to make it. but if you have the means to, and the time (it would be quicker to take a picture and draw-on or even use the box feature on instructables, than to draw it by hand) i think that the final result of would of been much more professional.

On a second note, this is from a point of view of me trying to figure out how this was built, im just going to say that i am having a hard time following instructions, such as in step 5, i have no idea what i am connection, to where, and from where.
Hey latobada! I agree with you about the lack of photos, it's kinda hard to figure out whats going on. Basically this hack is not really a mini TV hack at all, its a mini video monitor hack. These old camera viewfinders are simply tiny video monitors that will display a composite video signal (the kind you get out of a DVD player, VCR, or the side of a video camera). They are normally constructed with three wires leading into them, a positive power lead, a common ground, and a positive video lead. All you have to do is figure out which leads are which through trial and error, then hook the positive power lead, and the common ground (the negative lead) to a power source, and then hook up a video source to the positive video lead, and also the common ground lead, and you should get some sort of image on the screen. Also, in step 4 of this instructable, Googfan recommends hooking up a 9v battery to test the leads, this might not be a good idea as in my experience these monitors seem to run on 3v-6v, but you can find out for sure by taking a reading off the original camera output. If the video appears fuzzy or dim, you can normally adjust it by turning the mini POTs the should be somewhere on the driver board, on Googfan's step 6 they are the two little blue things just under the screen. Anyway, here are some photos of an old effort of mine, running off an old motorola phone charger, and displaying the output from my DVD player.
Tazom Everlong6 years ago
dude! i have almost the same CRT viewfinder and i cant get it to work, can you contact me about which cables and etc etc.!!?!?! PLEASE!
Hi, I've also got a b&w crt viewfinder in my misc. box of stuff and I'd like to use it as a video monitor. It came out of a Sony CCD-F70 camcorder and has 4 leads. How do you figure out which wire is which through trial-and-error? Thanks.
grenadier (author)  kishida7 years ago
srry bout the delay, hook random leads to random battery leads, things should happen. btw, my instructabe got updated
grenadier (author)  latobada8 years ago
I already bult the tv and did not want to re-take it apart to take pics
you could of done zoom-ins
grenadier (author)  grenadier8 years ago
also the step 5, you need a knowlage of circuit schematics.
how would you make this just a tv and no oscilloscope?
i done that it shows just static.....damn : (
12V6 years ago
will it work if you use an old but working 5inch tv(12v version) and connect the four magnet wires to an oscillator (horizontal) and vertical to what you want?
12V 12V6 years ago
also use a transformer with an isolated output for each circuit instead of two or even three batteries use a single 6or 12v input instead feel free to ask for a wiring diagram to make the power supply.
grenadier (author)  12V6 years ago
that wouldn't work because when one coil draws current, the magnetic field is weakened, affecting the other coil. They would attenuate eachother.
12V grenadier6 years ago
they are voltage regulated and the transformer is twice rated for the current and higher current will not mean less voltage.
grenadier (author)  12V6 years ago
Yes it would. Ive tried it but i did not have a variable oscillator. (what we do w/ the portible tvs now? they dont work)
Hey, I have really wierd geckos who will sit at the end of their cages watching tv, when i let them roam around on my bed or floor they just stop and stare at the televison, i leave it on when i go to school because they seem to appreciate the company =D

But i've been thinking about making a miniature television screen that i could plug into my little movie box so that my geckos can watch stuff on it (they seem to really enjoy watching movies i have on my ipod)

How will i do this?
grenadier (author)  Thundertydus6 years ago
Interesting. what species are they? Well first you would have to build this mini tv, tnen you simply connect the "video in" to a vcr/dvd thing.
Leopard Geckos, Well, leopard gecko now, one died *cries* nine years old
Anyways what im asking is how would i construct this?
grenadier (author)  Thundertydus6 years ago
The instructions on how to make the tv are in the instructable!
what are the details on the 10uf capacitor?What kind of Relay? where can I get the 2m potentiometer meter?
Ah so there was an instructable for a crt oscilliscope i suppose mine is moderelty diffrent though (have a look(go ahead(i dare you))) Why use such a small screen though why not perhapse use a small tv (my instructable)
grenadier (author)  The 4th Doctor6 years ago
That's the point. This is an ins. for a TINY teleision that, w/ a flick of a switch, can be turned into an o-scope
Didn't really zone in on the tv part interesting I suppose it would be cool if you got 2 of those viewfinders and made a headmounted display maybe hook it up to well I don't know something. maybe one of these days ill get my hands on one of those
grenadier (author)  The 4th Doctor6 years ago
Tried. But ended up blowing out one. Gave up because old cameras are hard to come by.
Im gonna try it, or a single one you hold up to your eye
grenadier (author)  Warlrosity6 years ago
I did do that once but it got boring after a wihle. Check out my website. I made it into a nightvision helmet. www.mrgoogfan.co.cc
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