HOw to make an LED display?

[Buriedcode]

Hi,

I'm sure you are all aware of 7-segment LED displays, as well as the dot-matrix types. Well, I've been hunting for various types/colours for a small project of mine and although I can find some white ones (very expensive) I realised that I also need to have some illuminated symbols. The type you see on VCRs, DVD players, and many many home appliances.....

I would like these symbols to be 'custom' but I cannot afford the huge expense having a prototype made up by a company...so it looks like I'm once again going to have to go 'true DIY' and make a display from scratch. Along with the saymbols, I might as well attempt to make the 7-seg displays as well, so its all in one unit. That way I can control the colours of the entire unit.

I know that 7-segment displays are really just a block of plastic, routed out for segments, then filled with a diffuse epoxy, and a PCB containing LED's underneath.

If anyone has worked with manufacturing these, or tried making custom LED-lit symbols befire, I would appreciate some advice on materials and construction. I'm planning on getting some moulding kit which should make my life a whole lot easier. For word 'symbols' or 'legends' would it be wiser to simply route out an area to cover the word, and cover that with a black mask and diffuser?

As always, I'm really an electronics guy, this sort of construction (plastics, glue) is out of my league :/

Thanks, hope someone can help.

BuriedCode.

 

[saeed_pk]

Hi

when u think about 7- segment LED display that is not too expensive might cost 30-35 cents but if u want to make it your own then that is a tidious work

when i was doing this i faced many difficultied i did it with nirmal LED's i made a big 7 Segment for a Clolck which was not avail in the market due to size
if u connect all of them in parallel then their glow is faint but when u do both paralle and series connections then glow is fines after making one segment u may cover that one with the brown glass or so

u might need plastic ,glue or so

remember u cant fabricate an original Seven Segment but u can make it from normal LED's

 

[Buriedcode]

Hi, thankyou for your reply!

You're right about it being 'tedious work'..I've done a few little 'tests' for lighting up shapes, took hours...

Unfortunately..I was hoping for a fairly small display, about 5" square. So getting 8 digits, several bargraphs and a few symbols on there with standard LED's isn't really an option...although...some SMT chips are tiny, and might just do the job!

if u connect all of them in parallel then their glow is faint but when u do both paralle and series connections then glow is fines

I guess that depends on the available current/voltage. I always try to wire same colour LED's in series, as its more efficient (only one resistor used, so less power disepation)

remember u cant fabricate an original Seven Segment

I'm determind to do so I'm sure it can be done, theres nothing magical about them...its just a real hassle moulding plastic and making custom PCB's, soldering SMT leds and then potting it all in epoxy. Of course...for digits...if I can find some cheap white/blue ones, I'll gladly use them. But then I wouldn't have the option of an RGB 7-seg display (oh yes, it will happen ). Since I've found a source of cheap very small RGB leds (2x3mm I think) I'm using them wherever I require an SMT LED. I'm so indecisive, its nice to have the option to change to any colour I want...including white.

Thanks for the advice,

BuriedCode.

 

[jaloman]

What about this small project.
**broken link removed**

 

[Buriedcode]

hi jaloman, and thanks for your input

Its a nice idea, and that would help a great deal in controlling a large LED based display. Especially if I have a circular bargraph, with 30 segments, and several symbols to light up. thankyou.

Update:

I'm still stuck on the 'mechanics' of it all though. Almost all 'matrix' type displays simply use 5mm/3mm leds. They *can* form shapes and symbols, but you'd have to stand back a good 30 feet to see it as one solid shape. Whereas, I'm really after something like this:

**broken link removed**

as you can see, we're not simply talking about a 'grid' or 'array' of led's. Underneath the light cavities is of course an 'array' of SMD LED's, but the plastic moulding and diffuser means an 'area' can be evenly lit, by one LED. (just a thought, would a CNC machine be able to route out those sort of symbols?)

I know i'm probably the first to attempt this, since they are nearly all custom made by OEM manufacturers, and if I ever need one of these for a product, then I will of course outsource it. But developing a good, simple method might help others to bring something 'unique' to their projects. After all, a 'decent' LED display would beat a small LCD (16x2) application hands down, given the contrast.

Also, I know that there are many devices out there that use this sort of thing, if I could get hold of some displays from them (VCR/DVD/CD players, car stereo's) then that would of course be ideal. I've got some VFD panels from high-end car stereo's on the way, these will do for now.

Regards,

BuriedCode.

 

[martin martinez]

the only trouble i see is the size you want it , because there are leds made in rectangular shapes and the very smal ones for dots, so you can arrange almost any way and if need is you can dremmel them just watch your way so dont touch the inners. i've seen leds worked in many different fashions this way, and is a lot easier and cheaper. it also makes them give a more diffused light. you can sculpt any color ultra bright leds to your needs, lines, dots or whatever is your choice.
just need a steady hand. take some time and try a few and maybe youll be able to make your own custom signs from one or two leds.

 

[bigaussie]

well

You can use double sided pcb to construct matrix, of use a single sided on with lot of jumpers.