Lm3915 counter up down by buttons

Thread Starter

ekremgusani

Joined Mar 20, 2011
157
IMG_5131.PNG Hi, can somebody send me schematic for the project i want to build please?
I want to build an lm3915 counter up and down by pressing button for up or button for down.
I want the leds to go on 1 by 1 till all 10 are on and then if press the down button the leds to go down one by one.
I managed to build one by schematic i find on the google but the down counter doesn't work properly and if you count till up and let it the led will go down by itself as the capacitor dries.
Can someone make proper counter by LEDs?
 

MrChips

Joined Oct 2, 2009
23,849
LM3915 is not a counter circuit. It is simply an LED VU display indicator that expects an analog voltage as input.
To accomplish what you are attempting to do will require a digital counter and a digital-to-analog counter driving the LED array display.

For a display that reacts linearly with the input voltage, use an LM3914 instead of LM3915.

If you do not want to use LM3914 /LM3915, use CD4017 decade counter.
 

Thread Starter

ekremgusani

Joined Mar 20, 2011
157
LM3915 is not a counter circuit. It is simply an LED VU display indicator that expects an analog voltage as input.
To accomplish what you are attempting to do will require a digital counter and a digital-to-analog counter driving the LED array display.

For a display that reacts linearly with the input voltage, use an LM3914 instead of LM3915.
Can you make me schematic please?
 

MrChips

Joined Oct 2, 2009
23,849
4017 doesn't count back and it's counting up only and only by turning 1 led while the previous led it's turned off. I want all led to be on while counting up and to turn off one by one while counting backwards
Yes, you are right. Thanks for catching that.
Then what you need is an UP/DOWN counter such as CD40193 plus encoders, or a serial shift register such as CD40194 or 74HC194.
 

Reloadron

Joined Jan 15, 2015
5,991
If you want to count up (increments) and count down (decrements) using a push button for each direction you may want to consider a Up / Down counter like the 74192 as an example. A simple Google of 74192 Circuits will bring up a dozen circuits which can be easily modified to do what you want. The circuit shown in this thread could be modified to do what you want to do.

<EDIT> I see Mr. Chips has already addressed the 74192 family of Up/Down counters.

Ron
 

Thread Starter

ekremgusani

Joined Mar 20, 2011
157
brisi.jpg brisi.jpg brisi 2.jpg
If you want to count up (increments) and count down (decrements) using a push button for each direction you may want to consider a Up / Down counter like the 74192 as an example. A simple Google of 74192 Circuits will bring up a dozen circuits which can be easily modified to do what you want. The circuit shown in this thread could be modified to do what you want to do.

<EDIT> I see Mr. Chips has already addressed the 74192 family of Up/Down counters.

Ron
74192 can count the leds in arra
If you want to count up (increments) and count down (decrements) using a push button for each direction you may want to consider a Up / Down counter like the 74192 as an example. A simple Google of 74192 Circuits will bring up a dozen circuits which can be easily modified to do what you want. The circuit shown in this thread could be modified to do what you want to do.

<EDIT> I see Mr. Chips has already addressed the 74192 family of Up/Down counters.

Ron
Ron, can you please help me to build that counter? I managed to made with the 4510 and 7442 ic, that all led are on but just the one that moves is always off and opposite all leds are off and just the one that moves up down is on. I need all leds to power on and to stay on in array while counting and when counting back I want the leds to power off one by one till all of them are off. I am just starting to learn with electronics by watching youtube videos. Please help me, can you make me schematic? I am not using ardoino or programer.View attachment 134226
 

MrChips

Joined Oct 2, 2009
23,849
Switch contacts create switch-bounce and you do not get a clean single UP/DOWN pulse.
You must debounce your mechanical switches.

Here is an example of a switch debounce circuit using two NAND gates:

 

Reloadron

Joined Jan 15, 2015
5,991
One problem I see is you will get a dot display and seem to want a bar display. Looking back at your post. That is you sequentially want to light LEDs (Up Count) and then be able to sequencially extinguish them (Down Count). I am not sure how to go about that with a simple circuit. One possible, and I have no idea if it would work would be using a counter like the 74192 which gives a BCD out. That BCD (Binary Coded Decimal) output could drive a D / A (Digital to Analog) converter which would drive your LM3914. That would be one way to generate fixed value analog steps. Additionally as MrChips points out your push buttons will need some switch debounce.

Ron
 

Thread Starter

ekremgusani

Joined Mar 20, 2011
157
One problem I see is you will get a dot display and seem to want a bar display. Looking back at your post. That is you sequentially want to light LEDs (Up Count) and then be able to sequencially extinguish them (Down Count). I am not sure how to go about that with a simple circuit. One possible, and I have no idea if it would work would be using a counter like the 74192 which gives a BCD out. That BCD (Binary Coded Decimal) output could drive a D / A (Digital to Analog) converter which would drive your LM3914. That would be one way to generate fixed value analog steps. Additionally as MrChips points out your push buttons will need some switch debounce.

Ron
Can you please try to make me schematic as i having trouble for over a 3 hours now.,.
 

Reloadron

Joined Jan 15, 2015
5,991
All I presented was an idea. I do not know if it will or will not work and right now I really don't have time to make a schematic.

Ron
 

ebeowulf17

Joined Aug 12, 2014
3,282
Anyone else?
I have a rather convoluted idea - it's probably a lot more parts than Reloadron's, but maybe just a little easier to wrap your head around.

You say you've already made a circuit that will activate LEDs in the sequence you want, but the problem is you only get one active at a time. What you could do is start with that circuit and add a bar graph LED driver chip (http://www.ti.com/product/LM3914) and a lot of resistors and diodes.

A bar graph LED driver chip can be easily configured to light all the LEDs up to a certain number, with the number lit being a function of input voltage (they're often used as voltage meters or audio meters.) You could take each of your current outputs and run it through a voltage divider (pair of resistors to ground, tapped where the resistors meet) and then feed that output through a diode. Each voltage divider would be set to deliver a different voltage, maybe something like :
1st output 0.5V
2nd output 1.0V
3rd output 1.5V ... Etc.
(you'd have to account for the diode forward voltage drop when choosing voltage divider values if you want the post-diode voltages to be linear like this.)

The cathodes of the diodes would all be joined together and connected to the input of the bar graph driver. This way, whichever output was active would deliver a corresponding voltage to the driver, which would then light the corresponding number of LEDs.

This solution uses a lot of resistors. It's about the least elegant solution I can think of, but I think it would work if you can't get the BCD -> DAC concept worked out.
 

dl324

Joined Mar 30, 2015
12,911
I managed to build one by schematic i find on the google but the down counter doesn't work properly and if you count till up and let it the led will go down by itself as the capacitor dries.
Can someone make proper counter by LEDs?
It could be capacitor leakage that's causing the problem. Does it work as expected if you press the discharge (down button) soon after the capacitor is charged?

Is the mode pin really floating? That gives you dot mode, not bar.
 

Thread Starter

ekremgusani

Joined Mar 20, 2011
157
I have a rather convoluted idea - it's probably a lot more parts than Reloadron's, but maybe just a little easier to wrap your head around.

You say you've already made a circuit that will activate LEDs in the sequence you want, but the problem is you only get one active at a time. What you could do is start with that circuit and add a bar graph LED driver chip (http://www.ti.com/product/LM3914) and a lot of resistors and diodes.

A bar graph LED driver chip can be easily configured to light all the LEDs up to a certain number, with the number lit being a function of input voltage (they're often used as voltage meters or audio meters.) You could take each of your current outputs and run it through a voltage divider (pair of resistors to ground, tapped where the resistors meet) and then feed that output through a diode. Each voltage divider would be set to deliver a different voltage, maybe something like :
1st output 0.5V
2nd output 1.0V
3rd output 1.5V ... Etc.
(you'd have to account for the diode forward voltage drop when choosing voltage divider values if you want the post-diode voltages to be linear like this.)

The cathodes of the diodes would all be joined together and connected to the input of the bar graph driver. This way, whichever output was active would deliver a corresponding voltage to the driver, which would then light the corresponding number of LEDs.

This solution uses a lot of resistors. It's about the least elegant solution I can think of, but I think it would work if you can't get the BCD -> DAC concept worked out.
No, u don't understand. U understand all wrong.
I want to make a up down counter with two switches. I want led to light in bar mode not dote mode as 4017.
I made one as you can see on above schematic I uploaded earlier but the leds countdown by itself as the capacitor dries and doesn't count up down by 1, it starts good but then at the number 4-5 start to count by 2-3 numbers at once and same when counting down. So my circuit is not good!
Can anyone else can figure how to make up down counter circuit by lm3914/3915 ic snd and with two switches, one for up and one for down?!
 

Thread Starter

ekremgusani

Joined Mar 20, 2011
157
It could be capacitor leakage that's causing the problem. Does it work as expected if you press the discharge (down button) soon after the capacitor is charged?

Is the mode pin really floating? That gives you dot mode, not bar.
It start to count till number 4-5 good then instead to count by 1 led up its counting by two so instead to show 6 leds its showing 7 then pauses it self even i click the up or down switch. When is finally at number 10 led then it counts down by itself as the capacitor discharge, the capacitor doesn't have any leakage.
I can change the lm3915 to count dot or bar mode as i put the switch for that mode.
 

Thread Starter

ekremgusani

Joined Mar 20, 2011
157
I have a rather convoluted idea - it's probably a lot more parts than Reloadron's, but maybe just a little easier to wrap your head around.

You say you've already made a circuit that will activate LEDs in the sequence you want, but the problem is you only get one active at a time. What you could do is start with that circuit and add a bar graph LED driver chip (http://www.ti.com/product/LM3914) and a lot of resistors and diodes.

A bar graph LED driver chip can be easily configured to light all the LEDs up to a certain number, with the number lit being a function of input voltage (they're often used as voltage meters or audio meters.) You could take each of your current outputs and run it through a voltage divider (pair of resistors to ground, tapped where the resistors meet) and then feed that output through a diode. Each voltage divider would be set to deliver a different voltage, maybe something like :
1st output 0.5V
2nd output 1.0V
3rd output 1.5V ... Etc.
(you'd have to account for the diode forward voltage drop when choosing voltage divider values if you want the post-diode voltages to be linear like this.)

The cathodes of the diodes would all be joined together and connected to the input of the bar graph driver. This way, whichever output was active would deliver a corresponding voltage to the driver, which would then light the corresponding number of LEDs.

This solution uses a lot of resistors. It's about the least elegant solution I can think of, but I think it would work if you can't get the BCD -> DAC concept worked out.
Can you make me schematic so i can try?
 

ebeowulf17

Joined Aug 12, 2014
3,282
No, u don't understand. U understand all wrong.
I want to make a up down counter with two switches. I want led to light in bar mode not dote mode as 4017.
I made one as you can see on above schematic I uploaded earlier but the leds countdown by itself as the capacitor dries and doesn't count up down by 1, it starts good but then at the number 4-5 start to count by 2-3 numbers at once and same when counting down. So my circuit is not good!
Can anyone else can figure how to make up down counter circuit by lm3914/3915 ic snd and with two switches, one for up and one for down?!
I'm pretty sure I understand what you want. Perhaps you misunderstood my suggestion. Start with this circuit you posted above:
IMG_2413.JPG
If you hooked a different voltage divider up to each output from IC2, you would get a different reference voltage for each state (right now you get one LED lit, driven by an output from IC2, right? Instead you would provide power to just one of the many different voltage dividers you had created.) The reference voltage created by your voltage divider would be fed through a diode so that it doesn't interact with the resistors in the 9 other voltage dividers. That reference voltage would then be fed into the output of a bar graph driver, which would illuminate the correct number of LEDs.

If I get a chance this evening I'll post a partial schematic showing what I mean.

Don't get me wrong - I know this idea is silly because of the vast parts count, but I really don't think I'm misunderstanding your intended circuit behavior.
 
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