[YASSDT] Yet Another Seven Segment Display Thread

[marcos.placona]

Guys I've been thinking about build a small thermometer to put on one of the bedrooms that is able to display the actual temperature on three 7 segment displays.

I know everything I need to do, and have all the necessary components in hand (Three 7 segment displays of course, three 4026B and the DS18B20)

I reckon I'll need 3 pins for that, and I want to be able to display the "." when you have 22.5º for example.

I've done a small messy prototype, and everything looks good.

My problem now is that I'm starting to draw this circuit on the strip board, but found that it can be such a pain, as there's actually 6 connections that have to be made between my 4026 and my seven segment displays.

This will use a HUGE space on the strip board, as I'll have wires going everywhere from the 4026 to the displays.

My question is:

Has anybody here did something like this on strip boards, and have any advice to give me?

Also, I'll take this post to ask something I've been meaning to ask for quite a while:

I want this to send data to my computer, so I can check it over the internet from wherever I am. I have the rev-ed's download cable and the serial to USB addaptor. Can I use this cable to grab data from my device without having to do any modification?

According to some of my researches here, I believe I can, but I just wanna make sure.

Thanks in advance

 

[inglewoodpete]

I know you've already got your 7-segs and 4026s, but I'd say it would have been cheaper and simpler to use a 2x16 LCD. As you say, you have a lot of wiring to do

 

[marcos.placona]

I know you've already got your 7-segs and 4026s, but I'd say it would have been cheaper and simpler to use a 2x16 LCD. As you say, you have a lot of wiring to do

Yeah, I've got 2 LCD's over here too, waiting to be used. I got those MMs-E Dog mentioned here some time ago, and I even have one which will display it perfectly:

I'm just trying to figure out how to wire it, as it still doesn't make much sense for me, so if anyone here has this kind of experience, that'd be much appreciated.

Here's the pinout:

 

[eclectic]

Marcos.
With one board, I think the minimum size will be about 80mm x 50mm.
See the diagram.

Last year, I built a 3 x 7 segment display using 3 x 4026.

It was HORRIBLE to wire and looks awful!

But, if you've got LOTS of patience and excellent eyesight, (I have neither),
then the best of luck.

Like Pete says, a backlit LCD display is much easier.

e.

 

[marcos.placona]

Yeah, I'm gonna go to the LCD, much easier and not so messy.

Thanks

 

[MoonGoon]

Hey marcos

i am currently working with a project using 5 7-segments, i have used no 4026 chips at all. just a single 28X1. Using the Charlieplex technique.

The wiring is very simple. just a single resister per segment. For your strip board, the lines simply go from your Chip to your first display, then the lines for the next display come directly off the first display, and the third off the second .. etc.

It makes stripboards very clean (most of the time) and you can have up to 8 displays with very simple modification of your code.

Just a thought, if you wanted to get rid of those 4026's and free up your board. If you want more info on Charlieplexing, just google it.

Hope that helps.

Moondogg

 

[marcos.placona]

Hey marcos

i am currently working with a project using 5 7-segments, i have used no 4026 chips at all. just a single 28X1. Using the Charlieplex technique.

The wiring is very simple. just a single resister per segment. For your strip board, the lines simply go from your Chip to your first display, then the lines for the next display come directly off the first display, and the third off the second .. etc.

It makes stripboards very clean (most of the time) and you can have up to 8 displays with very simple modification of your code.

Just a thought, if you wanted to get rid of those 4026's and free up your board. If you want more info on Charlieplexing, just google it.

Hope that helps.

Moondogg

Then you'd end up with something like this right:

I'm just not really sure about how the code would be for that. You will need 8 pins anyway, so my picaxe 18X would do it by a blink of an eye, but how do you control that?

Do you have any examples of how to control it?

Cheers

 

[manuka]

I'm currently a 5 minute expert on Charlieplex & could offer ideas, but tend to ponder your initial brief. Just WHAT are you really trying to achieve- maybe a general awareness of indoor temps while in bed? No need for ½° resolution for that! 7 segment LEDs of course are power hogs, BUT they can readily be seen clear across a darkened room, which few LCDs of the same size can match. Considered a 20M? (I've just done something in this line in fact with a single sequenced 7 seg. LED => http://nz.youtube.com/watch?v=Fw0lHWN1pj0 Stan

 

[marcos.placona]

I'm currently a 5 minute expert on Charlieplex & could offer ideas, but tend to ponder your initial brief. Just WHAT are you really trying to achieve- maybe a general awareness of indoor temps while in bed? No need for ½° resolution for that! 7 segment LEDs of course are power hogs, BUT they can readily be seen clear across a darkened room, which few LCDs of the same size can match. Considered a 20M? (I've just done something in this line in fact with a single sequenced 7 seg. LED => http://nz.youtube.com/watch?v=Fw0lHWN1pj0 Stan

Yeah Stan, I've seen it, but in fact I'd prefer to display it in at least 2 seven segment display. Three would be just to brag myself to some friends

BTW, Stan have you seen my PM to you?

 

[moxhamj]

I have a drawer full of 7 seg displays but each time I think of a project I remember that LCD displays are a lot easier to wire up. And they use less power. Organic LEDs are another option - I found this display on ebay - same chip and pinout as a LCD display, but visible across the room. Search for "OLED display" on www.ebay.com

 

[marcos.placona]

I have a drawer full of 7 seg displays but each time I think of a project I remember that LCD displays are a lot easier to wire up. And they use less power. Organic LEDs are another option - I found this display on ebay - same chip and pinout as a LCD display, but visible across the room. Search for "OLED display" on www.ebay.com

Yeah, but the ones I've got are pretty visible too, I'm just trying to figure out how they work

 

[Mycroft2152]

I have this LED screen. can it be driven by a PICAXE?

http://www.core77.com/blog/default.asp?p=3

Myc

 

[inglewoodpete]

Myc: I'm sure the Chinese could interface a PICAXE. What would you recommand as a buffer?

Marcos: You could use a display like that but you'ld have to turn down the central heating a bit.

More seriously, if you really want to use 4026s and 7-segs, you would be better of using perforated 0.1" board (strip board without the strips). You then would use point-to-point wiring but would need to use a lot of care routing the wires and soldering.

 

[chris.celovic@hotmail.com]

LCD Convert

Hi

After rooting around with 3 x 7 seg displays, (all very formative and learnt a lot.... etc etc) Mycroft had a chat with me and convinced me to use a LCD. I have a very sexy 20 x 4 blue LCD with 1 wire.

I found that 3 x 7 segs were taking too long to count up, and they could not be seen in the field (this is critical), and hellishly too many wires...