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So much trouble, so little time...

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IT'S ALIVE!!!

The first 10 LEDs work in dot-mode! Accepts a 0-6VDC signal and turn on or off sequentially from left to right with increased voltage. Thank you so much, eric.

Now, for the rest...
 
[QUOTEIT'S ALIVE!!!
The first 10 LEDs work in dot-mode! Accepts a 0-6VDC signal and turn on or off sequentially from left to right with increased voltage. Thank you so much, eric.
Now, for the rest... ][/QUOTE]

Thanks for letting us know.
There is goldmine of knowledge on this site, its simply a matter of using the correct tools to extract it from the experienced members.

I see your other thread, I would suggest when a 'helper' asks a question or asks you to do a simple test, reply with the information he is asking for,
Close up pictures of your project, should be in focus.

Also keep the drawings you post a lot smaller, I could see my house on one of your drawings.!:D
 
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I am not ungrateful, but if I don't understand the helper's question on a problem I don't understand myself, how am I supposed to ask the right questions correctly?

Thanks for your interest. The drawings I create saves me time by collecting them from a toolbox of electric symbols I've made over the past few months. Our company's electrical schematics are all A3-size. At least the efficient pdf's make for small attachments. Also, especially on some future projects I'm going to post over there, the complexity will see the diagram explode!
 
hi,
You have to install as Administrator on Win7, did you download and install the Visual Basic runtime files as stated in the text.
When you getting it working, you will see that the module is intuitive.

I spend a lot of time in SA, in the PE area, never heard the donkey bit.

So, I got your simulator working. How do I now get the second LM3914 to light up the next 10 LEDs in sequence to the first? Still in dot-mode, until I can figure out what values of resistors I'll need to go into bar mode?

Thanks so far.

EDIT: I thought I sent you a pm regarding the donkey. You may or may not find it useful info. Let me know if you didn't receive it.
 
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hi,
Top left of the sim image is a 'Slave to #1 box ' click/check the box to link the two LM's

Got the donkey PM ok.
 
That's good to know.

If my total signal is 0-5V, and the first 10 LEDs must light up from 0-2.5V, while the second set of 10LEds must light from 2.5-5V, what do I need to tweak?
What should Rlo, Rhi, RefAdj and RefOut be for LM1?
What should Rlo, Rhi, RefAdj and RefOut be for LM2?
V+ and Vled should both be 12V, since that's my power supply, yes?

And how do I get values for R3 and R4 for each chip? How do I complete the circuit?
 
Its as simple as this.:D

Do you have the datasheet for the LM3914, all the formula's for the components are described.

Changed the lower Vs to 12V
 

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Yes, I have the data sheet.

No, I don't get it... I see a formula for Rev Out V, I_LED, V_out, but nothing for R1, R2, R3 and R4. Time to get out of black box mode, and show me where to find the information, so I can attempt Kirchoff's laws there.

No joke - I need to learn how to do these things, if only for a matter of pride.
 
And this? Is that someting important? Survivability issues?

hi,
Survivability issues?...:D
This is a LM3914 IC simulator, if you read the legend 'Vin > Vmax' above the LED, its there to tell you that the Vin of 5v is greater than the Vmax value that you have chosen for the LM3914 display, thats all.

As you have the d/s to hand, look at the tables showing what the Vin range can be.

With the LM3914 you dont need to use Kirchoff's laws, only the maths shown in the d/s.
 
I would really appreciate an exmple calculation. I see nothing to help me specify those values mentioned above. And I see on my simulation that there is hardly any time difference between LED10 and LED11 switching on - how do I tweak this?

Also, how do I connect the second LM3914 in bar mode or dot mode? Which pins are connected to what?

LM1 & LM2:

Pin 2 = ground
Pin 3 = 12 VDC power supply
Pin 6 = Pin 7

LM1:

Pin 4 = ?
Pin 5 = 0-5V signal? Or to 0-2.5V signal, and how do I do that?
Pin 7 = ground via R3=?
Pin 8 = ?

LM2:

Pin 4 = ground
Pin 5 = 0-5V signal? Or to 2.5V-5V signal, and how do I do that?
Pin 7 = ground via R3=?
Pin 8 = ground

No special connections between any of Pins 10-18?
 
hi,
These two images are from the LM3914 d/s.
 

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Sorry, that didn't help me the first time, it probably won't help me now...

How do I set the sensitivity to 0.25V/LED index? The two LM don't light up their respective LEDs with the same frequency/interval/sensitivity. I don't understand. And the data sheets mean nothing to me. Remember that circuit 1 is the one I built first? Why would it work now, if I'm no inch closer to understanding what to adjust, what to look for, what to calculate? Pin connections? Do I need the 20k resistor between LED10 and LED11 for bar mode? For dot mode? I'm going in circles here...
 
OK, now I'm seriously worried.

Yesterday, one connected LM gave me dot-mode operation. This morning I connected Pin 3 to Pin 9 and got successful bar-mode operation. Now I've connected up the second LM just like the first (see attached pic) and everything's dead!

What the hell am I supposed to do? Back to post#1?
 

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OK, now I'm seriously worried.

Yesterday, one connected LM gave me dot-mode operation. This morning I connected Pin 3 to Pin 9 and got successful bar-mode operation. Now I've connected up the second LM just like the first (see attached pic) and everything's dead!

What the hell am I supposed to do? Back to post#1?

hi,
How am I supposed to able to help you with that description of the problem. everything's dead!

Please drop the rhetoric and tell me in some technical detail or show me with a posted clear image of your bread board.

The Sim image you posted also shows that the set up is totally wrong.
 

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OK, so I've started connecting LM 2, but before completing it, I first connected Pin3 of LM1 to Pin 9 of LM 1, then turned on power to see it giving me a beautiful bar graph. I had not connected LM 2 to power at that point. Now that LM 2 is connected only to the bar graph, nothing happens. LM 2 isn't connected to power or signal yet, since I want to know which size R I must employ for the signal voltage divider. LM 1 is still connected to the full 6V signal.

In my schematic, the connected lines are the solid lines, the dashed lines are what I am trying to figure out, but have not been connected yet, and the unconnected pins are actually unconnected on the circuit board.

I'm sorry if I fail to communicate well. I'd like to understand what I'm saying wrong.
 

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hi PC.
Got your image, can already see some errors, give 30 mins , will post back

EDIT:
Marked up image, this shows some of the errors.:eek:

I would suggest you now draw up a circuit for the full dual LM3914 project and post it.
 

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Did you get my pdf ok? I really find it easier to refer to that, since (I think) it's neater. Or should I try to make it a jpg as well?

Thanks for your markings on my photo, I'll get to it ASAP. But could you suggest values, please?
 
Here is the most recent photo. I don't have another 10k pot, unless you mean I must place +6V at Pin 4. How will LM 1 know what to respond to in that case? Shouldn't I divide the 0-6VDC signal with two resistors first?

How does the circuit relate to the simulation on the right? The simulation is correct now, isn't it? (It sure seems to work.)

Thanks again. Please fill in the blanks for me first, and I'll follow your instructions.
 

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No voltage supply to the LED's!
You are obviously not checking your project with the circuit drawings.

I would suggest you set the project to one side until have studied and learnt the basics of electronics.
IMHO there is no point in continuing with this thread, its now 60+ posts, other members may step forward to help.

Good luck with your studies.
 
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