Need LED assistance...

[audioguru]

Hi Willi,
I wouldn't use your bright LED at 50mA for this turn signal. Its absolute maximum continuous current rating is 20mA.
You must be careful when you see the word "peak". It usually applies for a multiplexed display, where each LED is lighted only for a moment and the multiplexer scans thru the rest of the LEDS before briefly lighting this one again. Therefore each LED is off most of the time and appears dimmer, so needs a higher peak current to appear normal.
Many LEDs have a peak current rating of 1A for multiplexing use. Their datasheet usually shows a derating graph showing allowable current vs time. This LED doesn't show that graph.

 

[jrz126]

" I realise that the very 1st time period of the 555 is longer than all the rest. That would cause the 1st sequence to end with all 6 LEDs lighted and a delay before they are turned off and the next sequence begins"
yea if that can be fixed it be perfect
here is the toggle switch schematic does it look right?
it shoudl be correct i found it on another website instructing me to to do it this way..
here is a site that might help you Audio with this
thanks
max
**broken link removed**
https://www.4qdtec.com/wfg.html
friend said this might help you with that problem where all 6 light up at the end and its slow..

I dont think that toggle switch is right, you need the mode connected to either ground or +VCC, it wont work without it (I'm using a LM3915 for my led project and I just discoverd this out tonight).

Here's how you'll have to do it (I'm not sure if you'll still use this circuit or what, its hard keeping up with this thread.)
the resistor i added will function as a pull up resistor. The box there is supposed to go to VCC some how the paint program got deleated off my comp so I had to use an impossible program to draw it.
Oh, I would think a 1k resistor would work for the pull up.

 

[audioguru]

Hi JRZ,
Never mind guessing about an unspecified resistor, just connect the mode pin directly with a switch as recommended by the manufacturer:

 

[Maxer]

" I realise that the very 1st time period of the 555 is longer than all the rest. That would cause the 1st sequence to end with all 6 LEDs lighted and a delay before they are turned off and the next sequence begins"
yea if that can be fixed it be perfect
here is the toggle switch schematic does it look right?
it shoudl be correct i found it on another website instructing me to to do it this way..
here is a site that might help you Audio with this
thanks
max
**broken link removed**
https://www.4qdtec.com/wfg.html
friend said this might help you with that problem where all 6 light up at the end and its slow..

I dont think that toggle switch is right, you need the mode connected to either ground or +VCC, it wont work without it (I'm using a LM3915 for my led project and I just discoverd this out tonight).

Here's how you'll have to do it (I'm not sure if you'll still use this circuit or what, its hard keeping up with this thread.)
the resistor i added will function as a pull up resistor. The box there is supposed to go to VCC some how the paint program got deleated off my comp so I had to use an impossible program to draw it.
Oh, I would think a 1k resistor would work for the pull up.

Hey JRZ i think audio is correct because i saw another circuit with similiar connection, if you have this IC chip can you test this out? and let us know what works for sure?
HEy Audio did you figure out how to speed up to the next sequence once 555 lights up all 6 LED's?
Thanks
Max

 

[Maxer]

would i also need 0.1uF ceramic cap at the face of the circuit board where i will give +V & -V to board?
"to compress those spikes u will need 0.1uF ceramic capacitor or u r ic will malfunction" thats what was suggested by one of my friends
what do you think?

 

[Nigel Goodwin]

would i also need 0.1uF ceramic cap at the face of the circuit board where i will give +V & -V to board?
"to compress those spikes u will need 0.1uF ceramic capacitor or u r ic will malfunction" thats what was suggested by one of my friends
what do you think?

You should fit decoupling capacitors at various points on your circuit board, one close to every chip would be nice?, but probably one for every two or three would be enough.

 

[jrz126]

Hey JRZ i think audio is correct because i saw another circuit with similiar connection, if you have this IC chip can you test this out? and let us know what works for sure?
HEy Audio did you figure out how to speed up to the next sequence once 555 lights up all 6 LED's?
Thanks
Max

I have the Lm3915 which is logorithm based, and the LM3914 is voltaged based? So it wouldnt be the same. I'm positive that you cant have the mode pin floating. my jumper came out of my breadbord for it, and I spent about 5 minutes debugging before I noticed it. connected it up and it worked again. Not really a big deal for when you build your circuit to test it (assuming that you breadboard it first and dont go straight to a PCB)

 

[Maxer]

would i also need 0.1uF ceramic cap at the face of the circuit board where i will give +V & -V to board?
"to compress those spikes u will need 0.1uF ceramic capacitor or u r ic will malfunction" thats what was suggested by one of my friends
what do you think?

You should fit decoupling capacitors at various points on your circuit board, one close to every chip would be nice?, but probably one for every two or three would be enough.

Okay how does this look
i added 4 new cap each one .1uF
also added a resistor
found it that way on a website searched for "Astable operation 555"
here is the website https://www.tel.uva.es/~tri/tutorial.htm
thanks
Max

 

[jrz126]

Hi JRZ,
Never mind guessing about an unspecified resistor, just connect the mode pin directly with a switch as recommended by the manufacturer:

Now that I think about it, I might have had a loose wire as well .

In the schematic above, is the +12V input supposed to be connected to the V- on the IC?

Also, I found this program awhile back, it's pretty handy to have for calulating the pulse from the 555


I never though about needing a decoupling cap. for this IC, maybe that's why the LED's flicker when I input a low frequency audio source. I'm gonna have to give that a try. Looks like I need to consult my datasheets more closely. :wink:

 

[Maxer]

Hi JRZ,
Never mind guessing about an unspecified resistor, just connect the mode pin directly with a switch as recommended by the manufacturer:

Now that I think I might have had a loose wire as well .

In the schematic above, is the +12V input supposed to be connected to the V- on the IC?

Also, I found this program awhile back, it's pretty handy to have for calulating the pulse from the 555


I never though about needing a decoupling cap. for this IC, maybe that's why the LED's flicker when I input a low frequency audio source. I'm gonna have to give that a try. Looks like I need to consult my datasheets more closely. :wink:

Sweet i guess this Circuit will work, I don't know why +12V is not connected to V- on IC on other circuits i seens it connected to PIN3 but Audio hooked it up that way. so i guess he will have to explain.
Max