Another great 16F628 project

[OY2L]

Another great 16F628 project at this link 15x7 DISPLAY

 

[Pommie]

I need to set myself up with a website so I can post links to example code. It appears I was one of the few that posted (past tense) example code on this web site. Even the great Nigel posted links to his site.

Mike.

 

[futz]

Another great 16F628 project at this link 15x7 DISPLAY

I'm currently tinkering with something kind of similar. I have an 18F2550 controlling one bi-color (red/green) 5x7 LED matrix (like the one at the top there, but red/green). It uses a 74HC4017N to handle the multiplexing for the 10 columns.

In this pic I'm still missing two transistors (2N2222A) and haven't wired the 14 rows to the PIC yet.

**broken link removed**

 

[blueroomelectronics]

That is some funky headsink on the LM7805

 

[Krumlink]

I saw that, it must be 2-3 inches tall

 

[futz]

I saw that, it must be 2-3 inches tall

Heh. More like 1-3/4" tall. Everybody seems to like that thing.

I have another with a big heat sink too:
**broken link removed**

And one with a Power Trends PT78ST105V buck regulator, rated at 1.5A
**broken link removed**

**broken link removed**

 

[AtomSoft]

OMG those pictures are great (and the supplies )

 

[futz]

OMG those pictures are great (and the supplies )

You probably already know, but you can get those from **broken link removed**. The heat sinks you have to source yourself though.

One caveat with those power supplies: You have to pay attention to which end you plug them in on the breadboard. Only one end works with correct polarity. Plug it in the other end and it's backward. I just recently build a VERY busy breadboard and left room at the wrong end for the power supply. Plugged in the power supply and turned it on. No magic smoke was released, luckily, but I caught it almost right away.

 

[Sceadwian]

Diode protection is probably not a bad idea in these kinds of supplies, the safety factor should outweigh the wasted power from the diode drop.

 

[OY2L]

I have used this homebuilt supply on my Breadboard for a long time and never need a heatzink at all, never get that hot,

 

[futz]

I have used this homebuilt supply on my Breadboard for a long time and never need a heatzink at all, never get that hot,

Ya, my heatsinks aren't necessary. I just like them.

 

[olly_k]

Diode protection is probably not a bad idea in these kinds of supplies, the safety factor should outweigh the wasted power from the diode drop.

Surely in this case the only way you could give effective protection would be by putting a reverse biased diode across supplies (to negative) and therefore shorting the supply or am I missing an obvious solution here?

How about permanently marking the breadboard for a particular orientation?

 

[olly_k]

I'm currently tinkering with something kind of similar. I have an 18F2550 controlling one bi-color (red/green) 5x7 LED matrix (like the one at the top there, but red/green). It uses a 74HC4017N to handle the multiplexing for the 10 columns.

In this pic I'm still missing two transistors (2N2222A) and haven't wired the 14 rows to the PIC yet.

**broken link removed**

Nice project you have reminded me I have got a corker of a future project, a board out of an old fruit machine with 36 5x7 display modules complete with some logic circuits to run the thing, must be serial data in but not sure how yet. I must attempt to work it out some day!

 

[futz]

Nice project you have reminded me I have got a corker of a future project, a board out of an old fruit machine with 36 5x7 display modules complete with some logic circuits to run the thing, must be serial data in but not sure how yet. I must attempt to work it out some day!

Wow! That's a ton of wiring!

I started out with two displays, but soon realized it was going to take all of those two breadboards just to fit the wiring for one. And it's not gonna be pretty!

Anyway, I'm having fun with it and learning some interesting things. My first schematic has already been trashed. It wouldn't have worked. Started building it and soon realized it was so wrong! So I'm happy that I didn't spend any more time on it than I did.

 

[olly_k]

Surely in this case the only way you could give effective protection would be by putting a reverse biased diode across supplies (to negative) and therefore shorting the supply or am I missing an obvious solution here?

How about permanently marking the breadboard for a particular orientation?

I forgot to add "and therefore shorting the supply should it be connected the wrong way round or am I missing an obvious solution here?"

 

[edeca]

Wow! That's a ton of wiring!

I started out with two displays, but soon realized it was going to take all of those two breadboards just to fit the wiring for one. And it's not gonna be pretty!

Did you see the 8x8 matrix LEDs on the same page? I planned on trying something similar with one of those. Do you have a schematic? Even a scanned hand-drawn picture would help.

Time to order a bundle of stuff from Futurlec, are the component bundles (e.g. transistors) any good? Or should I order a bunch of separate ones?

 

[futz]

Did you see the 8x8 matrix LEDs on the same page?

Yup. I didn't buy those from Futurlec though. I bought the 5x7 red/green's at **broken link removed** for $1.12 each (bought 8 to get the discount).

Do you have a schematic?

Only in my head so far.

Time to order a bundle of stuff from Futurlec, are the component bundles (e.g. transistors) any good? Or should I order a bunch of separate ones?

Unknown. I've only ordered from Futurlec once.

Usually if I want any larger quantity of something I'll order from Digikey.

 

[futz]

Ha! She works! Red-only till I get my just-received transistors installed, but the multiplexing works perfect. Spent some time chasing my tail with it until I realized that RC4 and 5 are input-only. Moved that line to RC7 and away she went!

These LEDs are nice cherry red. Look what my camera turns them into! I have yet to find a way to color correct LEDs. Any attempt to correct LED color throws the rest of the pic way out of whack, so I just leave em.
**broken link removed**

 

[blueroomelectronics]

The power jack is unplugged how are you supplying power?
I do like the danish zero

 

[Krumlink]

Probably through the ICSP cable, although it looks kind of hard to figure out.


EDIT: It is through the ICSP cable, look at the attachment.