Covering midbass pods with cloth

     In this post I will describe steps that I have done to build cover-ups for midbass speakers in my car. Here you can see how I made midbass speaker pods in the front doors of my car. As you can see, these pods look awful although they are very useful for any car audio installation. In this post I'll try to make them less ugly not to say "good looking". :)

     Since I have some minor experience working with fiberglass, it was decided, that the covers for pods will be made out of fiberglass because you can get whatever forms you like. The technology or the way to make them can be very different. It depends on the door trim itself, your skills and desire to ruin few days of your life. Different styles can bee seen on the Internet. If you want to have interior of the car as original as it could be, it is possible to have the pods be built in the door trim so it looks like factory made. It requires a lot of skills, material and fabrics selection etc.

      I went the easy way. 

     The first step is to take food film, fold it in several layers and attach that film over the speaker pod. You should align the film on every curve and edge of the pod. The film it self can be fixated with some paper tape or something that wouldn't allow the film to move out of the correct position. This is done to protect the door trim from resin that will be used to glue fiberglass while replicating curves and form of the pod.

     Unfortunately I didn't take a picture of this process. But I think you get the idea. Be extra careful to cover all of the pod and its surroundings, because if the resin (glue) will touch the door trim, you won't be able to clean it off.

     The next step is to apply glue (resin) and fiberglass squares so you would have fiberglass form of the speaker pod. I have described in details how to handle fiberglass and resin, so I won't do it again. You can look for older posts in this blog. If you are very talanted, you might apply fiberglass with one try and get the perfect form. I wasn't, so I was prepared to apply another layer of fiberglass afterwards.

     After few hours or minutes (depending on the proportions of resin vs hardener) you can peal off the food film with fiberglass cover and cut off the excess fiberglass.

This is how it looked for me:

       

      As you can see, it is far from perfect. But with the next layers of fiberglass I made the form to look as it should be (in my opinion).

     

      After I got the form right, it was time to cover it with cloth.
      I chose Alcantara "wannabe" cloth (something like suede).
      In this step I will not go in to details as it is described in my previous posts (Tweeter podiums).
     The only difference is with the stitching where cloth made wrinkles. Covering tweeter pods I sew cloth peaces together. This time I used only glue. And it turned out better then I suspected. 

After that speaker pod cover was attached to the wooden ring fo the speaker pod with few screws.

Audio Spectrum Analyzer Step #2

      This is a follow-up post on building audio spectrum analyzer. 

    In previous post I created circuit that could show audio spectrum on one 10 segment led bargraph display. Also in previous post I encountered problem with signal strength, so I have to implement solution on adjusting audio signal level.

    But before creating amplifier, I decided that I should stack up another led bargraph, so i would have 20 led segments in a row.

     This way I will have bigger range to test audio amplifier performance.

     The fundamentals of getting it done is wiring two LM3914 IC so that they would work "hand-in-hand". I.e. when signal is 0, both LED bargraphs should be blank (not lit), when signal is to the max, both LED bargraphs should be lit fully.

     While searching through the Internet, I saw different versions of combining these IC, but believe it or not, the best diagram can be found in official LM3914 datasheet. :)

      I recreated the diagram so it would be a bit more understandable taking out mode switch and rearranging LM3914 IC placement in original scheme. 

This is what I got:

   

Using this scheme, I created circuit on a breadboard:  

Don't pay attention to the resistor across the led bargraph. I rearranged it afterwards.

And this is the video of what I got:

      As you can see, signal from computer is only strong enough to light only one LED bar graph. So next step will be signal amplifier implementation. 

      At this point I was wondering, is the second bar graph actually working or is there a problem in my circuit. But when I disconnect audio jack, both led bargraphs light up. This is a good sign as I can see, that both ledbars are working. But, I will have to find out, why is it lighting up when I disconnect signal and how to prevent it. 

 

Problems: 

1. Implement pot to adjust LED brightness.

2. Implement audio signal amplifier.

3. Find out why both led bargraphs are lit when audio jack connector is disconnected and how to prevent it.
4. I should order few LM3916 ICs and try them instead of LM3914 as they are more suitable for audio signal metering.

Tweeter pods: Step #3

If you follow this project you should already read these posts:
   Tweeter pods: Step #1
   Tweeter pods: Step #2

    In recent blog posts I described how to make fiberglass front pillar trim with tweeter pods.

    At this point the trim is ready to cover it with leather or cloth. In this project I used artificial leather in cream color (since the interior for the car I'm building this project is white/cream color. In next posts I'll show pictures of pillar trim for my car which I covered with black alcantara-like cloth. 

   Since this project has the tweeters in almost 90 degree angle to the trim, there were problems applying the leather. You see, the more irregular shape is the trim the harder it is to put on cloth without wrinkling. 

  The shape of this trim is extra difficult so I had to apply two parts of leather. Two leather pieces should be put together at the corner of tweeter and trim (you'll understand it in the next pictures). The best way to join both pieces of leather is by sewing. Unfortunately it requires great skill and sewing machine. And a lot of testing, experimenting and failing. :)

   In this project I tried to join them as close as possible to get rid of the gap between both pieces of leather. 

I failed, but got great experience on how to do that in my next projects. Soon I will reapply leather pieces with sewing stitches for these pillar trims. Something similar to the picture:

   OK, so to attach leather to the trim I used glue. I can't find the name of the glue, but it looks like honey, it can dry fast and can glue leather, wood, plastics, metal, glass etc.

   So I cut out approximate shape of the leather cloth so it would overlap the edges of the trim (so I would be able to bend it around the trim edges afterwards. 

   Apply glue to the trim surface and to the leather. Then allow it to soak for 3-5 minutes and put the leather on the trim surface. It will glue almost instantly, so be precise and careful. Also try to get rid of the air bubbles underneath the leather. Don't apply the glue to all the leather and trim, try to take several steps to not mess it up at once. 

    The difficult part starts at the tweeter post angles. I can't really explain how did I do it. I used razor blade to cut the leather. You can see in pictures beneath that there are lot of flaws, but it was the best I can do at that moment. 

   After this drill hole in the trim, so tweeter wire would fit. 

   The next difficult thing is - how to attach clips so that trim would clip on to the pillar. 

   At this project I didn't attach clips because this fiberglass trim fitted perfectly in the car and didn't make any gaps between trim and pillar. 

   In my other project I glued the clips on the back to the fiberglass trim so it could be attached to the pillar. But more on that in my future posts. 

   So the result in car looks like this:

Tweeter pods: step #2

     Next step of making tweeter pods is to level the surface using filler. The filler must be intended for car repairs, because it is very resistant and it stays on the fiberglass. The car filler also has two components, so proportions of hardener should be read on the car filler label.

     I won't teach you how to apply filler, because that skill comes with lot of training. At the following pictures I only started to learn my way of applying filler. The idea is simple - you put on filler on the fiberglass trim that we created in the last blog post. When it has hardened enough, you have to use sandpaper to get rid of unevenness. I should add that the surface of the fiberglass trim should be smooth although if there are small dents don't bother - when cloth/leather will be applied afterwards, these dents won't be seen.
So this is what the fiberglass trim looks after applying filler:

     And after sanding:

      By now you should understand that when using sandpaper, wear respirator, because the dust from fiberglass and car filler can be bad for your health. And this is not bullshit. Small glass particles can stay in you lungs for a very long time if not even forever.


      Now starts the most difficult part - getting the angle of tweeter. 
This is how I did it:
1. Place the fiberglass trim in to car so it would fit as original. Then place tweeter in the chosen height and place a mark on the trim where tweeter should be. At this point it is important only to get the height (we will have tweeters at eye-sight level).
2. You should find appropriate back cover for tweeters. Usually they come together in the speaker kit. So you have to get cover that would be suitable for placing within a surface. Let me give an example:


This is NO NO, because with this back cover tweeters can be placed on car panel:

This is the thing were looking for:

3. You have to find some peace of PVC pipe or similar to work as a form for tweeter. The most difficult part is finding pipe that would have the necessary diameter. 

Let me illustrate why the PVC, and how to measure correct size:

     As you see from picture, the PVC pipe diameter should be enough to include not only tweeter size, but also decorative leather/cloth thickness. 

    When the necessary PVC pipe has been found you should cut off about 3 cm (approx the height of tweeter itself). Afterwards you should attach it at the marked point on your fiberglass trim. How to attach it? I used rivets. But it was only because it was OK for me. In other cases there might be too little space between inner diameter of PVC pipe and fiberglass trim to put in tweeter.

4. Now about getting the right angle for the tweeters. At this point you should already know in what angle tweeters should point in your car. So now take some kind of wire (I used copper). Attach it to the PVC ring from behind (drill a small hole in PVC). This wire will be used to lean the PVC pipe in the correct angle and then attaching the other end of the wire on the fiberglass trim. 

Like this:

Unfortunately I didn't take a picture of it, but in the next pictures you will be able to understand it.

5. When the angle has been adjusted, you have to get lady tights. They are made of nylon and are very stretchy. So when we apply them over our construction, natural smooth curves and lines appear.

      Try to fixate the tights in place with some duck tape. After that apply polyester resin (glue) on the tights, than apply fiberglass (preferably small squares) and don't press hard because you can ruin the shape.

       When glue has hardened, cut off the unnecessary parts of the tights as you see in picture above. 

Then it's time to apply car filler again. And sanding.... And filling..... And sanding...

New updates will follow...

Tweeter pods: step #1

     My goal with this project - customized fiberglass tweeter pods in front pillars.

     I would like to mention that this was my first project with fiberglass, so the result could be better. Training leads to perfection.

     So where to start? As every project - planing is crucial. It is important to know at least basics of car audio setups. Since every tweeter is different not only by dimensions but by sound characteristics, the best way to decide of the tweeter position is by experimenting. To do this you have to get some help. So when your car stereo is running, you have to hold tweeter in one of your hand (other person holds the other tweeter) and try to rotate it, change its location, position, angle etc. This way you can listen and decide in which position the tweeter sounds best. So - there isn't the "correct" position. Only the one you like best.

At this project I was making pods for my brothers car and audio system. He has car stereo with sound processor which is able to create sound delays (to create better sound stage and stereo imaging), so we decided that with the processor in place the best sound from tweeters are when they are at eyesight level pointing to the driver.

Motorized gadget: step #5

       So I got to the part of fixing iPhone to the motorized vent.

      This was quite a challenge because the phone has to be placed in perfect center or otherwise the system won't be able to rotate. Secondly to fixate screws and nuts, you have to be jeweller (that's why I used rivets instead).

So first I attached some aluminum ribs so I would be able to attach iPhone cover to the moving part.

        Next I drilled holes in the iPhone cover, that would match the holes on the aluminum ribs beneath. 

After riveting iPhone cover to the aluminum ribs, I had to ensure that vent system can rotate 180 degrees. It couldn't... That's why there are several unnecessary holes in the iPhone cover. :)

        So this works for now as you can see in the video below:

 Unfortunately there are additional problems that I have to solve. 

1. How to connect iPhone wires so that they would allow to move the center part.

2. How to disguise the vent so that it when iPhone can be seen, no other stuff is visible (like the center axis).

Motorized gadget: step #4

       In the previous blog posts I got trough with the main problems in circuits that control servo.

If you missed them:
Step #1: Voltage limiter from 12 to 5 V
Step #2: NE555 timer for servo control
Step #3: Problem solving with oscilloscope

      With the circuits working I had to proceed with the next phase - integration in the car panel.

      So the idea is to use the center console air vents from my car. Since I don't use these vents, I decided to sacrifice them in the name of my project.

      I took out the center part witch consisted of three separate parts. The best thing with these vents is that they are cylindrical, so they can be rolled 180 degrees. 

      At first I took the vent system apart:

        I had to modify these vents, so they could turn fully around. With a bit of pliers, knife and drill I got rid of small things that didn't allow the vents to move around.

Motorized gadget: step #3

OK, so I got trough the previous problems.

       First of all I applied heat sink to the transistor to cool it down. It's much better now, but still the heat sink is a bit warmer than it should be. Maybe some little fan will be attached. Since the heat sink doesn't get hot all the time I will proceed observing this process. For transistor cooling I used old heat sink from CPU and also applied special paste that would better distribute heat between transistor and heat sink. 

    About the second problem (described in last blog post) - I borrowed oscilloscope to see what is happening with the pulse signal that should control the servo.

    To see how the circuit works at first I didn't add the control current - power supply that produces current from 0-10V.

These are the results:

1. Potentiometer in the center position (on NE555 timer pin #5 current is 1.6V):

As you can see pulse signal is normal, nothing unusual.

Motorized gadget: step #2

      It's time for the next step. As I mentioned before, I want to create scheme/mechanism that would be able to control servo based on the current in car stereo remote wire (intended to switch on/off audio amplifier). 

To understand it better - when I switch on car stereo it gives current on the remote wire, which "says" to the amplifier: "Switch ON!". Scheme "sees" the current in remote wire and starts turning servo to the other end (180 degrees) that flips a panel in center console of the car. When car stereo is switched off, current in remote wire is gone and scheme turns servo the other way around (180 degrees back). 

To do this I encountered two main problems:

   1. Scheme and servo had to receive 5 V all the time.

   2. To control servo it has to receive pulse signal through control wire.

    

     The first problem solving is described in my recent blog post. I created scheme that can reduce voltage from 12 V (which is commonly found in car) to 5 V. The voltage can be adjusted with potentiometer. Scheme works well although, transistor gets very hot. Heat sink will be applied soon to cool it down.

      Information how to solve my second problem I found in the internet. But before that I'll try to explain about the basics of servo performance. Servo has three wires - plus, ground and control. To the plus wire 5V current has to be applied from the scheme that I created in the previous blog post. The fun starts with the control wire. To move servo, pulse signal has to be transmitted. If the pulse signal is 1 ms (approx. 80Hz) the servo will turn fully left, if the signal is 2 ms (approx. 80 Hz) the servo will turn fully right.

Motorized gadget: step #1

     Since I love technical stuff, I have many different ideas in my mind. Mostly they are useless but fun to create, plan and integrate.

     This time I couldn't let go of an idea about motorized panel in my car that would turn 180 degrees when car stereo is switched on. The panel should turn back 180 degrees when car stereo is switched off.  

A lot to do till then, but for now - I'm proud to say that I have finished the first phase!

Since motorization will be done by a servo which uses 5 V current, I encountered my first problem - where to find 5 V in my car?

     My father drew scheme that should convert 12 V to 5 V. With a list of needed components I went to my local radioshack. Few decades ago my father was a radio engineer so many components were already meticulously sorted in small boxes. 

So the scheme: