How to get data from an ethernet connection to an LED display?

[bigal_scorpio]

Hi to all,

I was wondering if it was possible to use the ethernet port of my laptop to send data, the time for instance, and have it display on a LED display some distance away?

I have a serial LED display or could make an interface if need be but I don't understand exactly what I need to do to accomplish it. I have a friend who can write the PC side of the issue as he is good with the PC software part, saying he would be able to do it with visual basic maybe. He says the software side would be easy enough to do if it were sending to another PC but doesn't have any electronics knowledge so like me he is baffled about the interface needed.

When I search the net all I find is POE (power over ethernet) which is not what I need as the display will have its own power supply.

Has anyone ever done this and if so can someone point me in the right direction for a way to do it?

PS I know it would be easier to send over the serial port but my laptop doesn't have one! Doh!

Thanks for looking..........Al

 

[Nigel Goodwin]

The ethernet port is a VERY, VERY complicated way of trying to do it - although there are PIC ethernet projects about.

Your laptop will have a USB port, so use a USB/Serial adaptor to give yourself a serial port and use that.

Or you could build a UBW, and use that directly from the USB port.

 

[amando96]

what about getting a USB-to-serial converter?
they are even easily made with simple electronics knowhow.

 

[bigal_scorpio]

The ethernet port is a VERY, VERY complicated way of trying to do it - although there are PIC ethernet projects about.

Your laptop will have a USB port, so use a USB/Serial adaptor to give yourself a serial port and use that.

Or you could build a UBW, and use that directly from the USB port.

Hi Nigel, are you keeping well?

I didn't think of that and I have a Velleman 8055 Kit I made some time ago **broken link removed**

Do you think that would be up to the job?

Regards..........Al

 

[Nigel Goodwin]

Hi Nigel, are you keeping well?

Fine thank you, I hope you are? - I'll give Rotherham a wave tomorrow as I go past (I'm taking some stuff to York Uni for my daughter).

I didn't think of that and I have a Velleman 8055 Kit I made some time ago **broken link removed**

Do you think that would be up to the job?

Regards..........Al

Looks like it should be fine - but somewhat larger than a UBW.

 

[bigal_scorpio]

Well if you get chance call in, there will always be a cuppa here for you mate.

Let me know if you want to and I'll PM my address.........Al

 

[Sceadwian]

Nigel that's a bit incorrect.. Generic ethernet is actually really simple, it's just high speed and not easy to interface with it's actually a very simple manchester clocked bitstream, as far as the software protocol layers go it's easier than USB is, and people have bitbanged that on PIC successfully.

SparkFun Electronics
might be up the original posters alley. They're several ethernet interface modules, about 35 dollars US that interface directly to logic level serial ports of a micro controller.

The convenient thing about ethernet is it allows internet access when connected to a router. Simple web interfaces could be built using them, and every machine in the world pretty much has an ethernet and some form of web browser built into it so it's universally accessible.

 

[kchriste]

I was wondering if it was possible to use the ethernet port of my laptop to send data, the time for instance, and have it display on a LED display some distance away?

How far is "some distance away"?
If it is less than 10ft you can use USB ver 1.1 or less than 16ft if you are using USB 2.0.
RS232 will go up to 50ft with ordinary cables. With better cables and lower speeds you could go even farther.
10BASE-T ethernet will go apx 330ft. Again you could squeeze more length out of it by using higher quality cables.

 

[bigal_scorpio]

How far is "some distance away"?
If it is less than 10ft you can use USB ver 1.1 or less than 16ft if you are using USB 2.0.
RS232 will go up to 50ft with ordinary cables. With better cables and lower speeds you could go even farther.
10BASE-T ethernet will go apx 330ft. Again you could squeeze more length out of it by using higher quality cables.

Hi mate,

The distance would only be about 10 feet. What I am tring to do is use my laptop to show the time ( and maybe other data like battery voltage) on a LED display in the dash of my car.

I have been running the laptop in my car for a few months now as ICE but wanted to use more of its functions.

I am running Centrafuse as a front end and bought the Velleman USB kit with a view to communicating with the cars Ibus (its a 1997 BMW 528) but couldn't find out how to do it, so I have the USB interface already.

I wish I understood serial communication better than I do and the MikroBasic manual does not help as all the things that require serial are already accounted for in software library routines eg LCD wire and I2C SPI etc but with no way for me to actually understand how it works.

So I can't even figure out how to communicate basically with the LED serial unit.

Any info is gratefully recieved.

Al

 

[kchriste]

Velleman USB kit with a view to communicating with the cars Ibus (its a 1997 BMW 528) but couldn't find out how to do it, so I have the USB interface already.

That should work fine then. It looks like it comes complete with a dll for your coding buddy.

So I can't even figure out how to communicate basically with the LED serial unit.

Could you post a link to the datasheet on the LED serial unit? It shouldn't be too hard to figure out. How many LED digits/segments do you need? You could possibly just use glue logic to keep the interface simple because the Velleman USB kit has 8 bits of IO to play with.

 

[bigal_scorpio]

Hi mate,

This is the only datasheet on the net for the display. below is a partial one from another source.

Thanks for helping.........Al

**broken link removed**

 

[kchriste]

While it is fairly simple to bit-bang the data, it would be pretty slow to load the data into the display. The Velleman USB kit has a latency of 20mS per command. To clock in 36bits would take a minimum of 1.44 seconds because each bit would take 2 commands. With basic glue logic, such as x4 CD4511's and associated LED displays, you could do it in apx 0.16 of a second because only a total of 8 commands would be needed.
So basically, where we go from here depends on how fast you want to be able to update the display.

 

[bigal_scorpio]

While it is fairly simple to bit-bang the data, it would be pretty slow to load the data into the display. The Velleman USB kit has a latency of 20mS per command. To clock in 36bits would take a minimum of 1.44 seconds because each bit would take 2 commands. With basic glue logic, such as x4 CD4511's and associated LED displays, you could do it in apx 0.16 of a second because only a total of 8 commands would be needed.
So basically, where we go from here depends on how fast you want to be able to update the display.

Hi again mate,

Can you expand on the latter, I have quite a few logic ICs and LED displays(non serial) so it may be the way to go?

Would it still get the data the same way from the PC?

Thanks again........Al

 

[Nigel Goodwin]

I would imagine that's a LOT more complicated, both in hardware and software.

Using a UBW you could program the 18F PIC on the UBW to transfer data directly and speedily to the target device, and the USB part is already done for you.

 

[kchriste]

The reason I chose the 4511 or 74HC4511 was that it has a built in data latch. That way you can put all 4 of the ICs BCD inputs in parallel which would use up only 4 of your 8bits on the digital output port of the Velleman. Each one of the remaining 4 output bits would go a LE (active low Latch Enable) input of a 4511. For example, say that the lower four bits go to the BCD inputs and the upper 4 go to the LE pins of the 4511s. If you wanted to send the number 1234 to your display you would output this hexadecimal sequence on the Vellemans digital output port:

E1
F1
D2
F2
B3
F3
74
F4

I can draw you a diagram if that was too confusing.

Nigels idea of using the UBW is good too if you want to spend the money on more hardware. But if you want to use the Velleman USB kit and DLLs, you are pretty much stuck with something similar to what I proposed.

 

[bigal_scorpio]

Hi again mate,

Yes, I think I do need a diagram please, I am no expert with electronics. I just muddle through. Most of the time I can follow diagrams and even expand on some, providing I can grasp the basic idea.

If I can see how things are connected it sometimes seeps into my fast decaying grey matter, every now and then I actually learn something.

Thanks for being so helpful............Al

 

[bigal_scorpio]

I would imagine that's a LOT more complicated, both in hardware and software.

Using a UBW you could program the 18F PIC on the UBW to transfer data directly and speedily to the target device, and the USB part is already done for you.

Hi again Nigel,

I don't understand a lot of what you are telling me.

I have not got as far as I would have liked with PICs so far, and I am sure that it is getting harder for me to take stuff in!

I would happily use something other than the Velleman but would I have any future expansion with your suggestion, like being able to communicate with the BMWs Ibus?

Thanks mate............Al

 

[kchriste]

Yes, I think I do need a diagram please, I am no expert with electronics. I just muddle through. Most of the time I can follow diagrams and even expand on some, providing I can grasp the basic idea.

OK, here ya go. The data I posted below may have to be inverted depending on how the Velleman outputs a logic high/low, but the basic principle is there. I assume a bit set to 1 turns the output transistor off (Makes the output high) in the example data below:
E1
F1
D2
F2
B3
F3
74
F4

 

[ericgibbs]

hi Al,
Does the laptop have a parallel printer port.?

Are you planning to use that 'bit serial' 4 digit LED for the Time display.?

If yes and yes, its possible to drive the remote LED thru the parallel port, using a small program in the laptop.

Have you finished all the paint jobs yet.?..

 

[Nigel Goodwin]

Hi again Nigel,

I don't understand a lot of what you are telling me.

The UBW is a cheap and easy way to connect external items to a modern computer, where you don't have parallel or serial ports.

UBW (USB Bit Whacker) Project