Flickering light - Help needed for Uni Project

[salguod]

Ok, this isn't really a technology question relating to a problem with something I have, but instead it is to do with a problem which I need to overcome for a piece of work for my university course, and I'm hoping this is the right place to post this.


Ok first of all, applying a context to the situation and outlining the problem. Our project at the moment in my Product Design course is to design a radio. For the radio which I am working on, I am looking at the relationship people have between sound and light or ambient light. One of my concepts, a very basic one at the moment, is just a radio with a lightbulb where the brightness of the bulb increases when the user increases the volume and visa versa. I was then told, or it was mentioned that it would be a lot more desirable if the bulb flickered when sound was played through the speaker.

So for example, when a person is talking on the radio, the bulb would flicker and when they stopped talking, the bulb would stop. A variation would be if the person was shouting, the bulb would flicker brighter than if the person on the radio was talking normally. The connection to the volume would still be there, but overall it would make the radio a lot more visual for users instead of an audio experience. Basic idea is pretty much hooking up the bulb to the speaker so you get a visual representation.


So my question is if this is possible to achieve this flickering, how easy would it be to achieve and what sort of equipment I would need.

We were given a pretty basic radio to take apart and use as a donor for our final radio. As far as I am aware we need to have a technical model ready and working, 3 weeks from today. I'm not going to post the sketches of my radio as of yet, as the form factor is not the important part at the moment, getting this additional functionality added to the radio is what I'm looking for just now.

Thanks in advance.

[viilaaja@pt cruiser]

if i read correctly you only need some sort of transistor, that takes in sound coming from the radio and goes throw it to speaker.
The transistor would be like tiny switch that flickered power on-off to the bulb.

i would say 2 input (1 for sound, 1 for bulb power), 2 output (1 for sound, 1 for bulb power), power and ground.

a relay might work, but i don't have a clue if there is fast enough relay to flicker the bulb.


Here

[PacketCollision]

An op-amp might do the trick, assuming you can get the right voltage out for the bulb. I'm no expert though. That would allow for variable brightness.

[salguod]

Thanks guys for the suggestions, it gives me somewhere a bit more definite to look now instead of just stabbing around in the dark, will have to look abit more into both of them to see which one could give me the best effect.

Someone else has suggested using a light organ, I'm assuming that this would work alright with a normal incandescent bulb without blowing it but it can easily be tested.

Thanks again, and if anyone has any more suggestions, feel free. I'll try and keep you all updated on the progress and how it turns out.

[WillDAQ]

I would have thought product design would include some basic electronics, if only so that you don't annoy the people who actually have to make your designs work?

Anywho, it should be a relatively simple implementation. Transistor could work if you want a digital on/off for the light but you'll likely find all sorts of power spectral issues trying to get the speaker signal to trigger the transistor frequently rather than just holding it on or off most of the time.

Op Amp is a far better option if only because you get an analogue output. However, you may still hit the spectral issues when it comes to the bulb as it's probably going to be limited to 500Hz by thermal inertia.

[tmbrudy]

http://skycraftsurplus.com/ledsound-to-lightkit.aspx

Thats a kit sold at a little store in Orlando, not where you are obviously but its a starting point for your search. Basically it has a mic that when you talk the LEDs flicker with your voice, they used to have a 120v one for controlling a regular incandescent bulb. You might be able to bypass the mic and wire it to the speaker, but the mic would work for proof of concept

I just graduated with my degree in Industrial Design, good to see another designer on here!

[salguod]

Originally Posted by WillDAQ

I would have thought product design would include some basic electronics, if only so that you don't annoy the people who actually have to make your designs work?.

The funny thing is that they do provide us with basic electronic skills but only enough as to cater for everyone, and since there is going to be at least twenty different radios created, everyone needs different components and the guy in the electronics lab doesn't have time to help everyone with their projects. I'm just thankful that in the selection process, when narrowing the 100 different concepts down to one, that any involving digital photo frames or touch sensitivity wasn't chosen otherwise I would be, well, screwed.

I did go to see the electronics guy today as well (not long after I posted my reply this morning), to see what he thought I should do to achieve this, but it turns out that he is away until next week and it just so happens that next week is a reading week, ie, a weeks holiday (yay, student life).

The kit you posted tmbrudy, is pretty much the same as what someone mentioned to me with the light organ, and I spend most of the afternoon researching them instead of doing CAD work, which I had finished.

Also, designers unite!?! Let the design talk begin It's good to see someone else here who has done (or there abouts) what I am embarking on. Good stuff.

[CD82]

Originally Posted by WillDAQ

Op Amp is a far better option if only because you get an analogue output. However, you may still hit the spectral issues when it comes to the bulb as it's probably going to be limited to 500Hz by thermal inertia.

I might be wrong but your eyes wouldn't perceive a bulb flickering at anything above ~30 hz as flickering at all, only somewhat dimmed depending on the duty cycle/average amplitude.

[salguod]

Right, wee update on what I have decided on. Gone ahead and ordered a Vellemans low voltage light organ kit which uses pretty much some of the things people have already mentioned like a transistor and such, and I made sure it was able to be powered by batteries since we have been urged not to make it mains powered probably so we don't frazzle ourselves.

http://www.velleman.eu/ot/en/product/view/?id=339223

It should hopefully arrive this week, but knowing my luck with ordering things and delivery times, they won't arrive until christmas, I'll then get the technical prototype made and should be able to post the results on here, on my way to producing a final concept model which should work, radio and all.

[WillDAQ]

Originally Posted by CD82

I might be wrong but your eyes wouldn't perceive a bulb flickering at anything above ~30 hz as flickering at all, only somewhat dimmed depending on the duty cycle/average amplitude.

That's a very good point, you've got me looking for a frequency response plot of the human eye now...

[CD82]

Originally Posted by WillDAQ

That's a very good point, you've got me looking for a frequency response plot of the human eye now...

Well, if computer games have taught me anything then it's that every game shows a noticeable stutter (observable time between two frames) below 20 frames per second, some stutter between 20 and 25 frames per second, and no stutter at all above 25 to 30 fps. Hence my conclusion that our eyes aren't capable of more than ~30 frames per second. Agreed, one could see the 60 hz flicker of an old crt, but only just, and only because every single pixel only glows for a very short time, while a conventional light bulb has a considerable afterglow.

[chvvkumar]

I did this sort of thing when i was getting into circuit building....

its really simple, take a resistor in series with an LED and connect the whole thing in parallel to the speaker (i am assuming you would be using a small radio and not the bookshelf like big speakers.

Try if it works out...

[salguod]

Thanks for all the advice so far, but I have another question which I would like to ask.

It is to do with making the blub increase and decrease brightness with the volume of the radio, so with the increase in volume the bulb is brighter and visa versa. Would I be able to do this straight from the volume potentiometer or would I have to get a regular potentiometer/dimmer switch for the bulb and mount it in such a way that it turned at the same time as the volume dial?

Keep in mind that the overall thing will be run off about 3 or 4 AAA batteries and not mains powered, so the simpler the better I think. Just as long as it works, even if only briefly, then it's fine.

We have been given an extra week to get the technical prototype finished since it was pretty much just myself and one other person of 20 odd who had ordered all the additional parts they needed in time, so this gives me an extra week to get things working properly, and if I need anything else to make it, I can easily pop to B&Q to get them.

[viilaaja@pt cruiser]

just get "stereo potentiometer" that has 2 potentiometers in 1.