After three weeks I got my Fon router in the mail

I removed the dinky little heatsink fan from the inside of the Fon.

I used the rest of the heatsink from my Inverter Project to use as an upgrade from the old one. I had to trim it down quite a bit to get it to fit. Here it is compared to the old one.

I had to trim down the fins also to get the cover to fit back on. They were a lot tall as you can see here where I compared the trimmed heatsink to the part I cut off earlier.

I have always wondered about using JB Weld as a thermal paste/glue. So I decided to give it a shot on this project. I am very pleased with the results.

I also trimmed the tabs off of the old heatsink, applied JB Weld to it and put it on the chip that I noticed always was scorching hot. Everything fits in the case and I might later enlarge the vent holes next to both heatsink’s for better airflow.

If you go here then you can get yourself a DS275 free! Just request it as a sample and they will mail it to you free. The schematics for this Serial to TTL converter is.

Thank you PwnStar for the old and new diagram.

This is an extremely easy circuit and the main part you can get free. The only thing better would be if you could get the whole unit free and already assembled. I will add pics when I get my free one and my actually paid for serial to ttl converter.

I purchased two more Fon’s for whatever reason. Truthfully I still don’t know exactly what I am going to do with them. Some ideas include:
* Universal Wireless Repeater
* Wireless Receiver
* Wireless Robot Controller
* Wireless AC Controller
* Web Host

I still do not know what all I am going to do with them, but I am that much more excited about having them.

I know that the first thing that I have to do is to secure my investment. Since they are renowned for overheating I will have to figure out a way to cool them better. Here is the internals of the Fon router unaltered.

To take the heat sink off you have to either unsolder or just cut the metal tabs that go through the pcb board. I choose the cutting method. The red circles are the tabs.

Now that the heat sink is off I can take off the metal cover under it. I do not understand how the designers can expect the heat to efficiently be transferred from the chip through the thick thermal pad, through the metal cover, through another thick thermal pad, and finally into the heatsink. I will eliminate most of those by only using one of the existing thermal pads between the heatsink and the chip.

Heatsink to chip size comparison picture.

with the extra pad and metal case gone, the metal tabs on the heat sink can now go through the pcb board and still stick out plenty enough to be soldered back to the board.

Everything back in place and the new heatsink arrangement installed.

While repeating the above steps on the other router I managed to rip off one of the tiny resistors… (The little speck on the white paper). But even with my shaky hands I was able to solder it back on with no fuss.

Specs So Far:

• I don’t know how hot the original setup ran but I would guess at least 160-180 F. on average with the lid on.
• Version 1 heat sink mod (large heatsink) = Chip 110deg F, Ram 110deg F.
• Version 2 heat sink mod (metal removal) = Chip 145deg F, Ram 125deg F.

the difference that the larger heatsink made is tremendous. If I took off the metal cover and installed it directly to the chip, then it would function quite a bit better. I am happy with the results and will leave it the same unless it breaks.

I decided to try and add some more vents to my original Fon. I decided that the best place is right above the main heatsink. This way the air will be drawn in from the sides and out through the top vents. I first made a border in which I knew that I couldn’t cut outside of. The border is the size of the heatsink except for the corner that has the fon logo on top.

Here is the view from the top. I made the cuts with a dremmel and a cutting wheel at low rpm’s. I choose a low speed so that the plastic wouldn’t melt as much or burn. I am very happy with the results and I am thinking about adding more vents above the ram heatsink and repeating the process on the other two Fons.

I decided to attempt something similar with the other two routers. I mapped out the area to cut and I decided to make three cuts. On the last router I noticed a difference between the ends of the cut due to the direction in which the dremmel rotated. So I thought I might go over each cut on this one twice. Once from either direction. I didn’t realize the angle that I was cutting at was quite off 90deg. So it didn’t turn out how I planned but it still works.

On the third router I decided to make a total of five cuts; Three large and two small. I learned from my last attempt to only cut from one direction and I am very happy how this one turned out. Since the heat sinks are smaller I made smaller vents to lessen the risk of a screw-up.

Here are all three routers next to each other. The middle one is the one that I cut from two directions and you can tell that the vent is wider. I don’t care for how it turned out but like I said, It works.

I ordered a usb to ttl converter so that I could plug it into any comptuer. After reading around on the internet I saw that only two wires are needed in the communication. Seeing as how I have multiple Fon’s I knew that I wanted to be able to use the cable on all of them. So I came up with the idea of using an audio jack to connect the Fon to the cable. Here is the Fon with audio jack installed.

The audio jack is very slimline and not noticeable. It was very easy to drill a hole and install. I would recommend this for anybody else attempting this project.

]]> http://www.Addictronics.com/projects/la-fonera/feed 0 http://www.Addictronics.com/projects/coherer http://www.Addictronics.com/projects/coherer#comments Sun, 10 Feb 2008 07:15:54 +0000 admin http://www.addictronics.com/projects/coherer A coherer is the earliest form of radio and is was one of the steps in achieving that. It consists of small metal shavings between two contact posts inside a small tube. When a radio or Electromagnetic Force (EMF) is received by a coherer, its resistance changes dramatically, as shown in the following videos and pictures. I have constructed my own coherer with a small piece of rubber tubing and two bolts from the local hardware store. By hooking up a barbecue igniter to some copper wire (allowing a spark to jump in between) I was able to create my own strong (but short range) EMF fields.

Here is the Coherer connected to my multimeter showing resistance.

A Close up shot of the Coherer shows the metal shavings (acquired by grinding on a piece of steel) are held between the two bolts inside the tubing. The piece of copper wire sticking out the side was just me playing around with different situations, materials, and whatever else I could think of. I do think that I have the metal shavings packed to tightly inside the tubing. I will try a less dense version later.

This barbecue igniter was purchased at the local hardware store with the rest of the parts. In my never ending curiosity I attached two pieces of heavily taped coat hanger wire to it. By bending them just far enough apart I could achieve a decent spark. By sparking practically everything in my house I was surprised at most. Certain silver and gold crackle picture frames would practically light up when sparked, I’m guessing the metal in the paint was conductive enough to allow this light show, check it out yourself sometime. Back to the project I then attached some copper wire to the bare ends of the coat hanger wire to get better range with it. That way I could be up to about 20′ away from the cohere and still see the results.

By attaching some more copper wire to either side of the coherer I noticed an improvement in the performance.

Here is a picture of the multimeter after spark. I have heard that if you use a small enough voltage through your coherer and measure the resistance that way, then you won’t have to reset it after each spark. Resetting it is basically thumping, or even gently tapping, the cohere to shift the metal shavings back to their previous state. When set off the metal shavings will micro weld themselves together, changing the resistance through the coherer.

Here is one video of the coherer in action. I noticed that the barbecue igniter makes the camera auto focus go haywire.

Videos

Notice when I tap the coherer that it resets back to no resistance.

I have no idea why the focus is freaking out.

This is the antenna that I use to pinpoint the location of wireless access points. With this parabolic antenna I can even determine where in the house the router is located! I bought a $2 strainer from Walmart and attached a usb WUSB54G V4 antenna to it. With that I am able to achieve 46dbi Gain!

Here is “Version 2″. It has gotten the best reception so far. I am hoping to improve.

This picture is the first version I made. It was only able to reach a max of 30dbi gain…only

Here are the statistics of version 1.

Version 2 statistics compared to Version 1 statistics.

Motorized Base

One day I came up with the thought of mounting the dish on some type of motorized base. I considered making my own from scratch and using servo motors. However I found that if I purchased a Usb Missile Launcher, 90% of the work was already done for me.

Here is the Missile launcher right out of the box.

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