Archive for July, 2011

Remote Control Switch

July 28, 2011

Over this summer I have been to some decent garage sales, although my subdivision’s garage sale has been moved to September (when I will be about 500 miles away at Michigan Tech).  One of the things I usually think about when deciding to purchase items is ‘how does it work?’.  This is probably pretty common among makers and hardware hackers, but it has always been a sticking point for me because I rarely want to use a device for it’s intended purpose.  One of the things that caught my eye was an old radio shack remote controlled coax A – B switch.  In my experience consumer electronics from this era (don’t get all pedantic on me, I can’t tell you a year, but in my experience things from a certain era have similar external properties, construction techniques, and internal properties) are constructed internally in a nice, easy to understand manner that operate how I would expect.  For example They tend to do things like use a linear voltage regulator to step the voltage down to what the chips require, rather than a convoluted set of diodes in series and resistors that are carefully selected to allow the exact voltage and amperage that the circuit requires.

Once open I found what I had assumed there to be, a voltage regulator, a couple of ICs whose datasheets were readily available, and a relay that is either switched on or let relax to form the two switch positions.  An interesting thing I found is that the reason this device is rated to work at 12 volts is that the relay is actuated by a transistor that directly switches the unregulated input on and off.  If you were to replace the power supply with one of any voltage from 7 to whatever voltage the 7805 can take you could replace the relay to match that (assuming the transistor that switched it could take it as well).  While I was trying to pin out the existing relay I eventually gave up and replaced it with a 12 volt relay I already had on hand.

I then ran that to a speaker cable spring clip thing that came off of an old amp some time ago, thus making it A Com Com B.  I set it up so when the light for A is on the red connector on the A side of the device was connected to common and vice versa.  I have no normally open and normally closed, I have A, B, and common.

This design could do with a latching relay so the coil does not have to be drawing power the entire time one of the two settings is actuated.  That, however is another project I would like to try which is a three way switch (or an n-way switch) that is just a button that switches the current position of the switch regardless of the current position.

The pictures that would allow you to build the entire device from scratch (re-construct the schematic from the board layout) are available at this link:

Razer Barracuda HP-1 Gaming Headphones mic build

July 15, 2011

Recently my local area was subjected to what I hear is called a ‘100 year rain’ it is apparently a rain so hard (for a given area) that a storm of it’s magnitude only happens once every 100 years (once again, it is for a given area and what constitutes a 100 year rain would vary from area to area).  My house was not hit terribly hard, the roof leaked in one room which may have destroyed some not-so-valuble crap in my attic that we have now taken as an oppurtunity to pitch said crap, the basement flooded a tiny bit since sometime in the past the sump pump had failed and we hadn’t noticed (this is a whole other story), but certain areas of Livonia had the basements flood entirely.  By entirely I mean there was at least a foot or two of water in the basement, there is some controversy about whether or not the city had the opportunity to direct the storm drains into the freeway to prevent t from happening, whether it was truly a sewage backup, and plenty else that basically sums in up as the city not taking responsibility for their sewer system not being able to handle a ‘100 year rain’ (as I see it they know it will flood once a century and have no plan for that).

I guess that was my small rant for today, I can’t really feel too invested in someone else’s fight against the city since the only way it affects me is that I have some slightly damaged cool new stuff and I helped haul some seriously damaged heavy stuff out of a friend’s basement.  Moving on to the relevant topic for which this blog post is titled, one of the things this friend gave me while I was helping him clear out his basement was a pair of Razer Barracuda HP-1 Gaming Headphones.

Ovierview shot

My Glorious New Headphones

Since the headset I was using up until now was a 2.5mm mono headset from an old RadioShack telephone this was quite an improvement, but there were two problems: one, the left side was not working, and two, there was no mic.  let’s start with the seemingly difficult part, repairing the left side.  Now, recently I have decided to write a book (or probably it will be a wiki), A long time friend of mine mentioned that we would do something ‘by the book’ when I started to describe some of the mundane details of how I proposed we go about doing something, and after that I proposed we write a book of how we go about doing things.  From generic troubleshooting to favorite torrent sites and programs we use all the time, we would create a manual usable by people who are not us to do things the way we would.  It would kinda be a collective skill set that we have acquired over the years, the main thing that would be at the top of all the lists is ‘Try Re-Seating ALL Connectors!’.  It turns out that these headphones are meant for the Razer Barracuda AC-1 Gaming Sound Card, and it uses a DVI connector to pass all it’s 5.1 analog sound and 5. power to the amp.

the connector

That Damned Connector

Going off an another considerably shorter rant, I fully support the use of existing connector styles for tasks completely different from their original intent as long as they can not reasonably be confused with the connector’s new purpose.  Meaning I support the use of the DVI connector on this audio card and these headphones since I find it unreasonable for someone to mistake a pair of headphones for a monitor (also, there’s a key in the connector, a missing pin on the female connector preventing you from plugging a monitor into your sound card and potentially damaging in if they chose to put the 5v on a pin that might damage the monitor).  I do not support someone making a device that outputs 12v on a usb style connector (since they are commonly used for charging devices at 5v).  The key in the connector means that without a modification to the cable one would not be able to use a standard DVI cable to act as an extender for the headphones (not that you need to since they are so long).  The headphones have a small breakout adapter that puts all the audio inputs on to 3.5mm connectors and a usb one for power (the graphics cord comes with a similar adapter that turns it into 3.5mm female jacks).

the breakout cable

Said Breakout Cable

Getting back to topics at hand, all I had to do was plug the connector back together (it was not screwed together).  The real thing I actually did to these headphones was building a mic for them.  I cracked open the earphone of the headset using the three phillips head screws located just under the foam of the ear piece, once open it was fairly easy to read the pcb and figure out what the mic pinout had to be.

mic jack pcb

The mic Jack pcb (more detailed photos in the album)

I don’t know what the original headset did to light up the leds around the jack, but without internal modification to the headset I could not figure out how to light up them.  The tip of the 3.5mm phono connector is mic+, the ring in mic gnd, and the shield is the negative side of the leds that has to be grounded for them to light up, but when I connected the shield and ring together the leds did not go on, it was not until I connected mic gnd to the gnd pin on the leds on the side that the leds on the bottom lit up.

new gnd wire

New gnd Wire

I don’t know where the mic itself came from, it was in one of my parts bins with a very long cord on it, and a stiff wire for the last couple inches of the wire.  I chose it for that purpose exactly, I used the stiff wire to hold up the mic, I fastened it to the ring and shield of the 3.5mm connector.

new mic jack

I documented the disassembly process as well as I could and have it posted to my public google photos for anyone else who might find it useful.

Repairing Rock Band Drums

July 6, 2011

Continuing in my trivial repair series I bring you the drums.  One day (about a month ago) I was out driving around at night through my friend’s neighborhood the day before trash day when we come upon something interesting.  It turned out to be an xbox 360 set of rock band drums, complete except one of the far pads was completely broken off.  After I got it home it was trivial to replace the broken wire with another one (a twisted pair from a bit of ethernet cable) however the hardware repair proved to be a bit harder.  My normal approach is to use hot-melt glue or fiberglass resin to just put it back together, but with the forces that would be torquing the joint would shear off any adhesive quite quickly.  What I decided was that I needed was a rigid piece of material to bridge the gap and I needed to permanently affix the new material to the existing body.  For the material to act as a bandage I used some bits of a computer case (one drive bay cover and two strips cut from the case of a power supply) and for the adhesive I used pop rivets, they are cheap, fast, and easier than a nut and bolt.  Since the cable didn’t come with a USB connector on the end I ended up using a female USB b port salvaged from an old printer, insulated with some medical tape since we were out of electrical tape (we now have five rolls since I got fed up with not having any and went out to get some today).

Bottom Brace


Back Brace

Front Brace


USB Connection

I promise my posts will get more substantial as time goes by, trying to archive my own minor fixes I do on a regular basis (I do have some actual mods and hacks coming up soon).

Repairing Rock Band Guitar

July 3, 2011

Recently I went to visit a friend living in Mt Pleasant and while I was there he gave me this guitar that he said was his housemate’s, and it was broken.  Well, being me I naturally assumed that I could fix it no problem, and I was right.  Upon close inspection one of the 90° .1″ headers had all three pins broken off.  Not having a three pin 90° .1″ header I used what I had, in this case a 3 pin .1″ header salvaged from an old broken motherboard (probably a header for either a turbo button or a cmos reset jumper).  All I did was solder the header to the remaining pins to make a 90° header.  I have pictures of the entire board to document the orientation each connector has to be in for it to work properly.

in all it's glory

The Patient

opened for all the world to see

The Guts

not perfect, but it'll do

The Opperation

Oh, in addition to that the whammy bar had the spring broken off, I assume this is why it was dis-assembled in the first place, then the header got broken while it was open, and I fixed that by bending a little more of the spring into a loop and re-attaching it.