sound to light units.

I've seen a few people asking how to make lights flash to music, and I've always suggested a sound to light unit to do the job. I know you can buy them pre-made fairly cheap, but they may be harder to modify in a way to blend in with the car for those who want that.

Well I just picked up one of THESE today at my local electronics store. This would be easy to switch between on/off/flash by using a DPDT switch to either use the circuit, or bypass it.

I just thought I would put this out there for those who have shown an interest before.

Well I got it all put together, but I think I messed up the trim pot by over heating it because it doesn't have much effect, and the lights just kind of flicker all the time, no matter how little noise is in the room.

I was having issues with my soldering iron, the tip is dirty and my paste sucks.

any ideas here?? can you ruin a trim pot by getting it too hot? everything else should be fine.

With your meter set to Ohms.  Check the resistance between the 2 connections that are side by side.  Turn pot full CCW and check again.  Turn pot full CW.  Check again.  One or more of those readings should be the same as the value of the pot.  With the pot still full CW, check from one of those legs to the one on the other side of the pot.  Leave the lead on the lone connection and move the other lead to the leg on side of where it is now.  One reading should be a dead short and the other should be close to the value of the pot.  Now turn pot full CCW and repeat.  Should get the same readings, just opposite leg will show the short and the other will now show the value of the pot.  There may be other components paralleled with the pot.  If it is a 10K pot, you may only read 6 or 7K.  But the dead short thing is more critical of the pot working properly.

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Let's Go Brandon Brown. Congratulations on your first Xfinity Series Win. LGBFJB

ok i'll have to check a bit later, the pot is 220k.

If i jump the two connections side by side, the leds will light up about halfway, and it will flash with noise, but they never turn off.

if i jump one of the side by side connections to the single connection the leds turn off, and do nothing..... or they light up very dimly and do nothing.

when turning the pot, the lights will behave erratically, flickering on and off, and just simply turning off for a brief period while the knob is being turned.

I'll bust out the meter in ab it and check that, I've got a tire rotation to do, some inspection on my brakes/suspension and check my spark plugs, as well as other daily tasks.

should i test it with the power on or off??

I would say off, but since you have already shorted out every possible combination with it on.  I guess you will be safe metering it when it is on.   But no, turn it off before checking it.  If it is on there will be voltages present that may affect the readings.

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Let's Go Brandon Brown. Congratulations on your first Xfinity Series Win. LGBFJB

using 2m setting on my DMM.
Turn pot full CCW; .136
Turn pot full CW; .136

With the pot still full CW, check from one of those legs to the one on the other side of the pot.
Leave the lead on the lone connection and move the other lead to the leg on side of where it is now.
"left" side reads .136 "right" side reads 0,

One reading should be a dead short and the other should be close to the value of the pot. Now turn pot full CCW and repeat.
"left" side reads 0 "right" side reads .136

136 is a rough average value, it would mostly be 136, most times steady, but sometimes jumping around by 1 or 2 points, and once or twice it was a totally different reading, like 175.

I think shes dead.

Your pot is fine.

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Let's Go Brandon Brown. Congratulations on your first Xfinity Series Win. LGBFJB

really.....hmm....

I removed the pot, plugged it in, and the lights stay dimly lit, like really dim, and have no reaction to sound.

I may have a short elsewhere then?

That was what I was thinking.

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Let's Go Brandon Brown. Congratulations on your first Xfinity Series Win. LGBFJB

hmm, now I wonder how i'm going to find that.

I have a suspicion, but it's more of how will i fix that one if that's the cause.

well I checked, and looked it over, and nothing seems to be out of place, the right parts in the right places, and no apparent shorts anywhere.

reading some stuff on vellemen, it could be the wall adapter I'm using to power it. apparently it can cause noise and will keep the unit lit up with line noise.

I posted on their forum so I will see what they say.

Do you have a 470 or 1000 microfarad capacitor laying around?  You know those caps are awesome and fix all kinds of problems.  It should actually fix this problem for you.

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Let's Go Brandon Brown. Congratulations on your first Xfinity Series Win. LGBFJB

fix it's sensitivity to line noise??

I don't have any lying around, but I think I can pick one up tomorrow, my local shop should have something like that in stock.

Would I just connect it in series with the main power leads?

Connect the cap across power and ground.  Notice that the cap is polarized.  Make sure you do not connect it backwards.  The cap will eliminate the noise produced by the WallWart.

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Let's Go Brandon Brown. Congratulations on your first Xfinity Series Win. LGBFJB

alright, I picked up a 1000uf cap, put it on, and it still pretty much behaves the same. the lights stay lit even when I turn the pot all the way down, though when it's all the way down, the lights don't react to sound, just stay very dimly lit.

When I adjust the pot, the lights come on again, react to sound, but it's way to sensitive and they never shut off completely.... it seems like it's still picking up noise from somewhere.

Remove or short the microphone.  This will tell you if it is ambient noise or electrical noise.  If the mic is too sensitive, we can install a potentiometer to allow you to adjust it.

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Let's Go Brandon Brown. Congratulations on your first Xfinity Series Win. LGBFJB

ok, so I removed the mic. the lights stay on..... they don't flash or anything, but they are on. they remain dimly lit no matter what position the pot is in, unless it is fully turned on, then the lights are bright but solid.

When the pot is turned down they are just dim, and while the pot is actually being turned they flicker and flash like crazy until it stops moving.

i really don't know whats going on with it.

I do not know how it is supposed to do.   With no sound should they be off?  They should pulse when sound is present?   

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Let's Go Brandon Brown. Congratulations on your first Xfinity Series Win. LGBFJB

ya, that's what it should do..... just like light rings made for subwoofers and stuff.

generally when the sensitivity is adjusted correctly, unless there is a sound the lights stay off, they simply react to sound, or noise rather.

with this one, there is currently no mic, so the lights should be off. they remain lit and go nuts when i turn the pot.

I'll see if I can get a video of what mine is doing later, but no promises on that one.

still no word on the velleman forums though.

If it got better when yoiu installed the capacitor, try connecting it to a different power source.  If it is a 12 volt device try connecting it to your car battery.  If 5 Volt, use your car battery and a 7805.

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Let's Go Brandon Brown. Congratulations on your first Xfinity Series Win. LGBFJB

ok, I connected it to a 9v battery, and it seemed to fix the problem, however the pot still does see ma little wonky or the unit itself is REALLY sensitive.

even when connected to a battery, when adjusting the pot sometimes the lights will just go solid, and stop reacting to sound.... a little twisting of the knob and it will start working again.

Adding the 1000uf cap with the battery does make it work a little better but it still acts weird or is overly sensitive.

A carbon potentiometer, or any pot for that matter, is a noisy device.  If it is hard to get the sensitivity where you want it, we may have to build a resistor network and change the value of the pot.  Set the pot as close as you can to where you want it to work, then remove the pot and read from the lone pin to each of the 2 side by side and let me know what you get.

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Let's Go Brandon Brown. Congratulations on your first Xfinity Series Win. LGBFJB

I think I killed the output transistor now. I shorted out one of the LEDs by mistake, and now it doesn't work. I'm going to have to see if I can get another BC557 transistor.

I did order another one of these kits, but it probably won't be in for a couple of weeks.

I'll harass velleman some more and confirm if I did kill the transistor, it shouldn't be hard to get another.