Sunday, November 27, 2011

DIY Glove compartment light

Hey!

This weekend I managed to keep myself busy adding this this little but useful feature to my car. I have been facing a slight inconvenience in using my glove-box at nights due to lack of illumination and wondered if I can so something about it. Reaching for the dome light was not so convenient at all times.

So I inspected the thing, though for a few days and came up with something that can be done. Next was a shopping list. Electronic market in Sector 18, Chandigarh mostly fulfills all my odd shopping needs.

Here is an account of my little project.

Noticed that the Glove Box lid has a latch that catches a small loop attached to the underside of dashboard. This loop is further attached to a metal part that has 6 screws holding it from the underside. I took that peice out and it seemed like a good candidate to host the illumination stuff.

My plan was to attach some LEDs to the front of this part and provide a battery for powering them. It seemed not a good idea to tap into Car's own power supply for such a task. I also discovered that there was lot of hollow space between the dash and this metal part. So I decided to investigate it I can get the whole circuitry thing behind this metal piece.

I attached a big lump of modelling clay to this part and then tried putting it back and surprisingly there was LOT of space. Big enough to accommodate a standard 9V battery.

Those lumps were unmarked when the metal part was refitted suggesting enough hollow space behind it
Then there was a need for tiny circuits containing LEDs. After burning one LED while testing it with 9v battery, I figured out that there are some laws of physics to take care of as well so that I can use the 9V battery with those LEDs without blowing them up.

There are many helpful websites out there to help with the electronic calculations. I came to know that a 330 Ohm resistor is also needed along with two LEDs in series to balance the Current, Power and Voltage calculations.

Next step was to build those tiny PCBs that hold this arrangement:

The two pieces on the right were cut from this larger PCB readily available at electronic shops
X marks the place where I will drill holes for screws
Left over screws from PC components were used to secure those PCBs in the metal housing
Ready to accept components now
Here. Two LEDs and a resistor. Still to be soldered together

Components soldered and ready. The pieces are small and were hard to work with
Next step was to arrange for placement of these LEDs in the metal housing. Two holes for LEDs and one hole for the screw to pass through were needed.

Challenge was to drill those holes really precisely so that the LEDs should fit flush and the hole for screw should match the hole in PCB perfectly or else PCB may break or LEDs may be dislodged if force is used to fit them.

Some tips on drilling holes learned from my father few years ago came in handy here :-). Job was well done!
 
Drilled a hole, then another one precisely 7mm away from first one. Then used a bigger drill-bit to make those tapers

LED fitted from behind. Very neat. Screw is yet to come.
After those two, a third hole was drilled to allow the screws through.

Then came the circuitry. I followed the advice in internet to create my own circuit. It will use 4 LEDs two sets of LEDs connected in series. Each set then further connected in parallel. A diagram was drawn to understand it better. Tested it in a jig and then set out with the soldering and stuff.

The schematic containing all the components needed. Those are the standard symbols for LED, resistor, switch and battery

The switch was needed to make sure the LEDs are not always ON. They should light up only when needed that is, when the glove-box is opened. Hence a Micro-Switch was placed close to the metal latch and the circuit was caused to flow through this switch.

Used an old deodorant can to create a holder for on-off switch.
Here it is. The metal sheet, small PCB containing the switch and wiring running through it. I cannot find a better solution to this. Still think it is the ugliest part of the whole project.
Wiring all done. Battery was attached using a wire-tie so that it is easily replaceable when dead. Used a Duracell so that it lasts long enough.


Here is everything complete. I also used a glue-gun to hold wires in place. [Click to enlarge]

LEDs lighting up when the switch is released.
This done and installed in the glove box, I was now eagerly waiting for night so that I can see the effect of these tiny LEDs.

Wait ended in a few hours and to my surprise they work great! See for yourself (Excuse me f:or the graininess of images)

A view from the driver seat

Viewed from the front passenger seat.

That was all. All the components used cost less than Rs 200. The battery alone was above Rs 150. That excludes the cost of a Glue-Gun that was purchased for Rs 290.

Please leave your comments and questions if any. Why not give it a try?

See ya for now!

Wednesday, November 23, 2011

(re)Build your Desert Cooler

I am just re-listing the links to this project from my other blog. This project very well deserves a space in this blog but I am too lazy to copy, paste and reformat all the posts that went into this one. So here are the links in chronological order:
Thanks!

Tuesday, November 8, 2011

Fixing shoddy speaker install

Hey! After long time isn't it?

Anyways, Rosemary got an ECE recently. A Sony head unit and a set of 4 JBLs. Two of these went into the rear parcel shelf.

Even thought the installer was known around the city as among the best ones, more than one flaw met my eye. Checked out with friends and came to know that this is how it is done everywhere. That argument was not satisfying so in the back of my head I kept on thinking of the ways to fix it. I share the very fix here.

(You can click on the images to open in high res).

First of all, the flaws:
1. The cuts on the parcel tray were not exactly oval or to-the-size as was needed. Reason, lack of proper equipment. Lack of equipment at a professional installer! Strange.

Poorly finished edges

2. Protruding screws. The screws that were used to fasten the Speakers to parcel shelf were projecting beyond the shelf into the storage area. I got pricked by them a couple of times while manipulating stuff inside. Not done!


3. Shoddy connections. The speaker wires from the Head unit were simply twisted around the speaker terminals. That is so not acceptable. Got to fix that also.

Yukk!
 4. Difficult to remove. The clips that they installed were supposed to be removable. When it came to removing these, I was out of luck even after using all my strength. Imagine if a lady had to remove the shelf for some reason. Should be easy.

Those clips never came of manually. Were supposed to!

5. The biggest issue, my cricket kit won't fit in there anymore because the speakers hanged 3 odd inches into the storage compartment. I was serious about reclaiming my storage space. Also, running the risk to speaker damage from the stuff there.

Compromised storage

6. Rattle, the speakers weighed on the hinges and increased weight caused the shelf to bounce up and fall down with a big thud even on relatively small bumps. Earlier, the shelf was lighter and did not make that much noise. A fix was needed here too.

Now that all the issues are known, I thought for a few days and following is what I came up with.


Purchased some scrap cuttings from a sub-woofer enclosure manufacturer. Got these cuttings for one fourth the price of new board so it was a great deal:
Scrap pieces were perfect for my 9 X 6 inch speakers
10 of these for 100 INR.  I estimated like 400 for raw board. Now that is a deal
5 of them add up to approx 3 inches, enough for my application (Flaw number 5 above)

Next I traced out the outer shape of the speakers on a transparent plastic sheet (sourced from an old strip file):
Simply took the cover and marked the outline
 I wanted to give the setup a bit conical shape narrowing upwards, as my circular peices were bit larger then the speaker's longest diameter, I decided to make another line wider than the actual speaker size.

Carefully made 1/4-th of an arc of the larger oval on a plain paper with hand

The 1/4 th outer side traced on plain paper
 This quarter of an oval was good enough to be used to trace all the 4 quarters on the trace by twisting and turning it over and around. So the overall shape of outer oval remained symmetrical.

From paper to original transparent sheet.
Complete oval after 4 traces (each for one quarter of the oval)
Now for the inner side of the trace. Measurements from the speaker's lower side were taken and used as a basis for inner oval shape.

Paper's marks are based on measurements from speaker's underside
This fitment was used to create oval by connecting the 4 dots above. Worked nicely :-)
Cut the inner part to create the hollow that should now match the speaker
Size check. Its an A-OK!

Primary school tricks: Tracing inner oval to the final template. The line marked X is not to be used.
Next step was to patiently trace the above lines with a craft knife and cut out a template for use in rest of the project. I placed a piece of glass below for perfect cuts. Here is the cut out template:
We will soon see that it was worth creating this template.
Now I had to create symmetrical ovals that will together act as spacers for the speaker. So, markings were made and the ovals were cut for further assembly.
On your marks!

All marked. Template ensured exactly same sizes.

Drill a starting hole for the cutting out the inner hollow

Enter: my Dad's Jigsaw cutter

Takes some control and patience to make those cuts

One done. Nine to go. The width is equal on all sides. Apparent difference is because of camera.
Cutting those ovals was not easy, the Jigsaw had to be guided precisely along the cut line and takes some effort to guide a running motor on the line as well as push it forward at the same time. Also had to replace blade three times with new ones as the adhesive used as binder in the board wears out the regular wood blades. Luckily, had exactly three of them spare with me. :-)


Once these were done, next came gluing them together with wood-glue to make a set of 2 equal to height of 5 rings stacked one above the other:

Joining them: Step 1
 
Joining them: Step 2
Joining them: Completed
A bleak glimpse of the future :-)
Now for the fine work, because we used a bit oversize outer diameters, now we had to get rid of the extra material and shape them into nice looking towers closing in on the top.

Markings first. I used the speaker cover to make the marks. X sections will have to go
The first three will also be tapered down
Took away bigger chunks with a Hacksaw
Then used a carpenter's file purchased especially for the purpose. 125 INR
Closer to perfection. Filing the inner side as well
Done. Have a closer look!

Both spacers are ready for next steps
For scale, that is a 6 inch long Square. All debris created by filing! Lots of sweat.
Filing them down was the hardest step and took most labor. I wish I had a portable Belt-Sander or something to work this out. I had aching triceps and wrists the next day. :D

I did not told that an upholstery cloth was also purchased from the same vendor that provided the board scraps. This was to be used along with Synthetic Rubber glue to finish the spacers with some elegance.

Apply glue to the first surface
Apply glue to the second surface (cut out from the cloth with some margin for sides)
Margin for the sides to wrap up around
Apply, let dry, paste the sides too

Cut the excess
So what next? Remember the shoddy wiring? Here is the solution:
Bought the stuff, soldered together to make these connecting wires
Now, even a child will be able to connect-disconnect the speakers :-)

Affixing the speakers to tray needed some new holes in the tray. I used the same template to make perfectly spaced holes:
Red mark is a placeholder for a screw. Total 8 screws were added. 4 each for diameters and diagonals
Attached the template with marks and attached securely. Then used a drill to make holes for the screws.
The spacers were now  secured to the already sandpapered holes in the shelf using a C-Clamp (again, bought specially for this purpose). Fixing the screws was a piece of cake with the spacer already in correct place.
Fixing the spacers temporarily. This is the underside of the tray. Note the holes and spacer held below the holes.
Gypsum screws were used for maximum bite into the soft board
Nice!
Protruding screws all gone! That makes me happy enough :-)
Rest of the work was related to attaching and screwing the speakers to the other side of the arrangement and connecting the wires:.

Following images are pathetic. Please bear with me.

Nice looking connections. The other side will be plugged in to the wires from Head-Unit
Storage space reclaimed
Finished product: View 1of 2
Finished product: View 2 of 2
Last issue was shelf rattle on road. That one still remains. Maybe a task for this weekend!
That was all.



Questions/Comments are welcome.


Good night,
-Akashdeep

PS: The above actions were not performed by a professional. Feel free to try these at home :-)