Energizer Wiimote Induction Charger

An inductive charger is a type of wireless energy transfer system, it can also be called an air core coil transformer. It works by passing alternating current into the coils and air acting as a medium between them, the interacting electromagnetic field helps to induce inductive coupling. Wikipedia does a much better job of explaining it: Inductive Charging.

In this teardown, I’ll be featuring the Energizer Wii Inductive charger (model # PL-7581) and try to figure out how it works internally. This will be a challenging on-going project since some key IC components have been blackened for a reason to keep their functionality secret. I would like to add that throughout this teardown, I have come to appreciate the complexity of this device and commend Energizer for a job well done, they did their homework.

Now, this inductive charger works in the same way as the wireless charging toothbrushes. This schematic of the Interplak Model PB-12 electric toothbrush (although rough) is a good example of a simple inductive charger, and yes, it does indeed work nicely. Here is another example of a toothbrush induction charger at the picaxeforum.co.uk. Hack a Day has featured this technology in the past, “Inductive charging going mainstream“.

Readers are encouraged to help with this project, I’ll need information on capacitor values (since I do not own a capacitance meter) and help identifying any unknown IC’s and passive components (would the bus pirate help while cycling through charge on/off modes?).  Alternate uses for this project have been posted at the bottom. Also, clarification or explanation of the theory and operation is also encouraged. Posting comments or emailing (teamubermodder(*at*)gmail.com) us works.

I should first explain the various operational modes that are noticeable upon using the device. Placing the Wiimote and connected Energizer battery pack onto the charging dock, the red symbol lights up, when charging is complete, the symbol turns green. If the battery pack is not connected to the Wiimote and placed onto the dock, the red symbol flashes red in error and will not charge the pack. Just the charge peak detection through inductive fields alone is noting some incredible built in intelligence circuity.

To start, I removed the myriad of screws holding the bottom cover, then I opened it up and went straight to the good stuff.

Let me backup to the wall-wart transformer. It’s a 100 to 240 VAC 0.3 Amp 50/60 Hz (model # JSD-2710-050200, energy star rated device), quite capable since they only need to make one model to support the European and American markets.

As expected there are two inductive coils taped to the underside and a magnet resides in the center. The magnet appears to help the WiiMote stay on the charging dock since the accompanying battery pack also has a magnet. If designed properly, ferrite magnets can also improve the inductive coupling of the electromagnetic field between the coils, however I don’t think Energizer had that in mind for this application. The planar inductive coils appear to be wound in one layer (rectangular shaped) with about 16 windings. There are also two rectangular weights to keep the charging base properly weighted.

Top side of the circuit board exposed. The circuit board is basically divided into two, a side to manage each inductive coil. Model # shown on circuit board: HC-Q-0712 V4, built on 2009.09.01. Two large red ceramic capacitors reside in the middle (154J), 0.15 uF 250 volt. Various resistors and capacitors reside below the large capacitors. Note that the circuit board is double sided and the inductive wiring connected on the right and left.

Bottom side of the circuit board exposed.   I’m assuming that the IC, SO14 package, in the center is a microcontroller to manage the charging modes and various functionality. Could the IC be a Microchip or an Atmel product? Maybe the readers can help! The other two IC’s, SO8 package, have to be some COT’s (commercial-off-the-shelf) based devices, maybe power managment IC’s like battery chargers or current/voltage monitors to help the microcontroller judge battery charging characteristics. The large black capacitor is a 470 uf electrolytic, used to condition the dock’s power source coming into the black connector. There are two SOT23 6 pin IC’s towards the center of the board, I can’t find an explanation for those at the moment, these may be measurement IC’s of some sort. Two SOT package transistors, both are beside the SOT23 IC’s, the markings on them are illegible.  Beside each of the red capacitors is what looks to be a Zenier diode. Scattered around the board are various passives like capacitors and resistors, all surface mount. Lastly, note the indicator LED’s on either side.

The inductive charger comes with two battery modules, each are rechargeable. The rechargeable batteries are Nickel Metal Hydride AAA, 500 mAh in series to produce 2.4 Volts overall (but the voltage was not measured through a multimeter, so it must be connected through a power management circuit board). Here what’s inside of them…

Each module has an inductive coil taped to the backside and a magnet resides in the center. The planar inductive coils appear to be wound in two layers (rectangular shape) with about 17 windings per layer. Also, the coil is backed with stainless steel foil, this must help reduce the inductive field that would normally be absorbed by the batteries and the wii-mote. The coil is somehow connected to the + and – of the 2.4 series battery setup (noting again my theory of a connected power management circuit board).

Upon turning over the battery module, I noticed that the shell can be popped off. The two AAA batteries can be easily removed as they aren’t even soldered in, this may open the door for higher capacity NiMh AAA batteries! Where the batteries previously resided, there was masking tape covering up wiring and a small double sided circuit board. I carefully removed the tape, let’s take a look…

The circuit board have a few noticeable features, a small black bead temperature sensor monitors the temperature of the batteries during charging. There is a small SOT-23 6 pin package off to the side, looks to be the temperature sensor receiver (reads LM75 variant, check out Maxim IC’s information on these variants), the only SOT23 packed temperature sensor information that I could was at Maxim IC’s website (MAX6625). What looks to be a red Zenier diode nearby. Also, the typical blackened IC with no legible identification, I really think this is a microcontroller, same as what is in the base. Four diodes on the right hand side to turn the AC component of the inductive field signal into DC (Wikipedia: rectifier), they look to be 1N400X series diodes (rated for low voltages, small signal rectifier, 1N4001 would do). Four SOT package transistors, the two beside the IC have the same marking (431), the other two different markings (KL3P0) and (A1SHB). Lastly, the two wires from the inductive coil is in parallel with a small surface mount capacitor, leading into the diode rectifier circuit.

For the sake of my time on this project I’ll have to leave you here for now. To conclude, here are some of the things I’d like to look into:

• Measure all pins on the nameless blackened IC’s in both the base and the battery module. Monitor record all waveforms while invoking various charging and on/off modes, post pictures. Try to produce an IC pin diagram with functional pin descriptions. It would help us understand what’s going on here.

• Figure out what activates the charging dock into battery charge mode, if it’s a waveform from the Wiimote, more simply a resistance measurement or current draw prerequisite. If this is solved, the charging station can be used for alternate projects.

• Alternate uses for charging station:

1. Roomba or robot charge dock, the Let’s Make Robots! community would be interested in this.
2. Mousepad charger for wireless mouse.
3. Cell phone/Ipod charger (although li-ion charging characteristic must be taken into consideration, risk of fire!).
4. Or contribute with your own idea, let us know!

This will be stamped as a reader contributed on-going research project, stay tuned!

USB IDE CD/DVD Drive Conversion

My current Dell Inspiron 530 came with a single DVD drive and no IDE ports. On a limited budget and needing to burn media on-the-fly, I wanted to figure out a way to use my older IDE Ben-q DVDRW drive. Using an old USB hdd drive enclosure, I’ll show you how.

Difficulty : EASY - SAFETY WARNING, Shock Hazard
Time: 10 – 20minutes

Parts List

1 – Generic USB IDE hard disk drive enclosure with accompanying usb cable and power supply

Tools Needed

1 – Phillps head tech screwdriver

If a USB IDE hard drive enclosure works for a hard drive, why wouldn’t it work for an IDE cd/dvd drive? And in fact, it does. Windows has all the supporting drivers to make the modification work and should automatically install them. For this modification, any generic USB IDE hard drive enclosure will do.

I blew the dust off of my old Rocketfish USB hdd enclosure and went to work.

Using a screwdriver, I took off the supporting case screws and front cover, then carefully removed the internal caddy up from the surrounding chassis.

Turn the caddy around and remove the hard drive if present, there should be four screws on either side of the caddy to remove with the screwdriver. Next, unscrew the two usb ide controller screws on the back side of the caddy and unhook any front button cables. You’ll need the controller to hook up to your cd/dvd drive.

The controller is now ready to connect to the dc/dvd drive. Connect the IDE and power cable to the back of the drive.

Now, you will want to find or make a proper enclosure for this dvd drive and controller. Otherwise you’ll run the risk of electric shock if you connect the power with the controller board exposed! I cannot be held responsible for someone shocking themselves because they didn’t heed the warning.

Enclosure ideas:  Tupperware container, custom plexiglass box, actual dvd drive enclosure or etc.

Here I plugged in the cables to the new-found setup and let Windows automatically install the drivers. The USB dvd drive works as expected and I didn’t have to spend a dime!

In my situation, I placed the dvd drive with connected usb controller into the 5.25″ bay of my dell and plugged the drive into internal power. The controller’s usb cable was routed to the backside of my computer.

]]> http://ubermodder.com/usb-ide-hdd-to-cd-dvd-drive-conversio/feed/ 6 http://ubermodder.com/home-made-coyote-decoy/ http://ubermodder.com/home-made-coyote-decoy/#comments Sat, 30 Jan 2010 19:45:40 +0000 Trent http://ubermodder.com/?p=475

Home-made Coyote Decoy

Its winter, know what winter means? Well yes, ice fishing, but today … it’s varmint hunting!  Here is a cheap time delay coyote decoy MacGuyver’d out of some electronic pieces and some things from around the house.

Difficulty : EASY
Time: 30-40minutes

Parts List

1 – 0.01uF ceramic cap
1 – 100uF electrolytic cap
1 – LM555 Timer
1 – 9V battery with connector
1 – DIP Switch
1 – P-Channel MOSFET
1 – 100kΩ resistor
1 – 27kΩ resistor
1 – 100Ω resistor
1 – Power Diode
1 – small DC motor
½ – Fishing Pole
1 – Coonskin Cap (or something furry)
1 – small copper disk for counterweight (use your imagination)
Assorted Cable Ties
Electrical Tape

If you have to ask what you need this for, don’t worry you won’t ever need one.  However the timer circuit can be used in many other applications.

The main parts we have is a motor with a counter weight on it to shake the decoy, the top half of a fishing pole, which gives us something to put the decoy on and gives a nice whipping action, the timing circuit.  Finally something fuzzy and fluffy to catch the varmint’s attention, in this case, a coon skin cap from Disney World.

The timer circuit’s core is an LM555 timer chip.  The LM555 does alot more then just keep time, but in this case its just being used as an astable multivibrator.  The circuit below will put the 555 in such a configuration.

Resistors RA and RB and capacitor C2 are what control the duty cycle and frequency of the circuit.  With the values selected here a period of a little under 11 seconds with about 2 seconds on and just under 9 off.  If you want to have these times be different you can change the RA and RB values, but make sure that the RA value is at least double that of RB or the circuit will not oscillate, which is bad.  Also you can replace RA with a potentiometer giving an adjustable off time.  A more set of the timer equations and instructions are in the LM555 data sheet but the stuff below should be enough for most purposes. It may be a good idea to put the circuit on a breadboard before putting it on a PCB or Project Board so the duty cycle can be honed in to what is satisfactory for the particular application.  One simple way to hone in the desired duty cycle on the bread board is to replace the motor with an LED and appropriate driver resistor, then you don’t have a motor jumping all over the workbench.  Then its time to throw everything on to a PCB or project board.

Once the timing circuit is squared away its time to attach the motor to the half top of the fishing pole.  You can find a small motor around the house in many things.  This particular one was salvaged out of an old Xbox 1 controller.  A single cable tie through the top eye of the pole wrapping around motor works really well.  Guide the wire down the line guides and cable tie to the rod shaft.  As you can see the “small copper disk” has been soldered to some solid core wire wrapped around a few times which is in turn soldered to the motor to complete the counterweight.

Now to attach the rest of the stuff.  Electrical tape can offer a little water resistance if one of those plastic project boxes isn’t available, which is what was done here.

The furry thing can now be attached to the rod.  Don’t forget to leave room for access to the switch.  Also try to leave the battery a bit exposed so that it can be replaced.

Here’s a quick vid of what it looks like when its done.  One thing to note is the off time of the setup in the video since at the time the video was recorded it was setup for a 4 second off time.

High Beam Latch Circuit

Back in the day when Mazda was building the RX7 they apparently thought it would be really clever to make their high beam dimmer ECU controlled instead of making it a toggle switch like just about everyone else in the world.  Well it didn’t look so clever to me when this dedicated latch circuit failed on me, leaving my vehicle without high beams.  I threw together a little circuit that uses a T-Flip Flop to toggle the Dimmer Relay.

Difficulty : MEDIUM
Time: 1-2 hours (including wiring)

Here’s what I threw together to fix this little problem.

In this schematic I have a D-Flip Flop setup in a toggle config controlling the action.  In the circuit that I actually built and implemented I used a NTE754 T-Flip Flop IC, however that isn’t necessary and I could have used any D-Flip Flop that can handle the 11-15V DC you typically see in automotive applications.

The really annoying thing about how RX7’s do their electronic systems is they’re normally ground switching, which creates a few design headaches.  This design could be adapted to switching +12V by correctly biasing a P-channel MOSFET on the output for a high output and using an N-Channel MOSFET to take high input on the input side of the circuit.  Notice I have a reverse biased diode on the input, this is to stop the flash to pass in the car from back feeding through the circuit and actuating that relay.  If you’re going to modify this circuit to switch high, you’ll need to omit that diode.

Most vehicles make it rather easy to pull the relay out of the vehicle for testing as you see me doing here.  I threw a little LED (with a proper resistor) to help me see when the relay was in the NO position. After that I thew the circuit on a hobby PC board and put it in a project box.  Since this is for automotive application, I made sure to put RTV around the seams and holes of the box so that I didn’t get any moisture in there.  once that was done I hooked the input up to the NO dimmer switch and the output up to a wire that went out to the Dimmer Relay.  Also I made sure to put the +12V input on an ignition on lead from the vehicle.  Putting this device on a hot lead could kill your battery if you happen to shut the car off when the high beams are latched on as the relay will be left in the NO state and will draw ~100mA all the time.

Download the schematic in pdf

.brd coming soon

It sounds like this problem happens more frequently than you’d think.  If there is enough interest I would consider making etched units ready for to wire in to the car.  If interested email me.

Homebrew USB Charger

There are plenty of examples on the net on how to build your own usb charger, but since we didn’t have any on our site I figured I’d share it with you.  I found an old wall wort in my junk drawer that I couldn’t remember what it went to, so I figured it would be great to put it to a good use as a USB device charger. Because I didn’t have a clue what the maximum current draw requirements were for a USB device, I found the requirements on USB.org’s website.

Difficulty : MEDIUM - SAFETY WARNING, Shock Hazard
Time: 1 hour

The victim

To start off with I cut off the existing dc output wire of the wall wort and then cracked open the case (If you’re more patient you can probably get the wall wort open without destroying the plastic case, but I ended up putting it in a vice to crack it open). From there I de-soldered the AC wires that are attached to the AC outlet prongs and removed all the electrical innards from the plastic case. After that, I de-soldered the transformer output wires from the circuit board so I could re-locate the board after I installed it into its new box.  Since the voltage regulator is only rated for .5 Amps decided to remove and replace it with a 1 Amp LM7805 regulator. I ended up attaching a heat sink to it to keep the regulator cool, as shown below.  Btw, the transformer is rather over sized so I’m not worried about pulling too much power through it.

Next, I found a used project box to put the transformer and circuit board into. I didn’t re-use the original enclosure because I destroyed it while opening it up. I found an old beat up ac cord and an extra panel mount USB connector, then I drilled two holes into the project box to make room.  I soldered the new ac cord in onto the transformer and then glued the transformer into the project box with hot glue.  To get the stepped down voltage from the transformer to the circuit board, I ran another set of wires from the other end of the transformer to the circuit board.

AC to DC converter

Everything mounted in the box

After the circuit board was placed inside of the box I got to work on soldering the USB connector to a small proto board, shown above.  I decided to add the proto board to make mounting and connecting a couple of components much easier (plus when i tried to solder wires and components on to the USB connector pins directly I was running out of room and started creating shorts).  On the proto board I added a 1 Amp PTC (thermal resettable fuse) in series with the positive wire from the output of the AC to DC converter circuit and the output 5 V of the USB connector.  The PTC will provide device protection without the need to ever open the box and replace a fuse. I also decided that I wanted add a power indicator on the circuit, so a green led and a resistor in series with the 5V output was installed.  I installed the green led by drilling a hole in the top of the enclosure and used an clear-ish epoxy to mount it (I have to admit that the led is a bit dimer than I would have liked through the epoxy).   In order to charge the iPod correctly, the USB specification states that the data puts must be shorted together. As a precaution, I soldered a 51 Ohm resistor between the data pins on the usb connector. This way the pins are pulled together with low resistance rather than a short.  To finish things off, I attached the ground wire from the circuit to the ground on the usb connector and was ready to test.

Ipod Charging

Above, my 5th gen i pod video attached, it drew about 700 mA which was well within the limits of the supply hardware.

With the project complete I’ve got a functioning USB charger to keep at work which cost me nothing to put together (much better than paying $30 for one).

USB Charger Complete

Side view of charger

It is pretty rough looking, so I just hide it behind my computer monitor =).

Update (8/19/09):  Here is the circuit diagram for the charger.  Enjoy!

Circuit Schematic

Tyco Fast Traxx

Add a Tyco Fast Traxx, WRT54G router, tons of batteries, web camera, gps head, and user control via a laptop. What do you have? A wicked homemade wireless tank-like rover!

While it may not look like the mid 90’s commercial boasting the original Fast Traxx, it has taken on a whole new dimension of geek-like excitement Übermodder has to offer, (batteries sold separately).

I have to give credit where it’s due, if it wasn’t for JBProjects this rover system would be a lot harder to implement. I will be using some their code and hardware to jump start our rover in the beta stages, then later revisions of the project will upgrade with our own code and programming structure. I might go as far as minor autonomy to help the rover navigate in tough situations, stay tuned…

Goals

I wanted to build a rover that was capable of:

• Trolling around in mildly rough terrain, like grass and gravel.
• Expanded battery life of greater than an hour.
• Sport a real time camera system with a gimbal to view objects that aren’t directly in front.
• Laptop control with an easy to use interface.
• Wireless radio that has large bandwidth capabilities and decent range (150 yards).
• Low cost, low power micro-controller system.
• GPS tracking device.

So you may ask yourself why? The better question is, why not? The experience learned from a systems integration standpoint is priceless. Also the obvious fact that robots are cool!

FastTraxx

Here we have a virgin Fast Traxx, perfect for what I need. It sports twin mubachi 370 motors, tank tracks, and lots of space to cram electronics into.

Chassis Mods

Here comes the worst part, chopping and cutting into the poor thing. Terrible huh? Choke up those childhood memories and get going. The first goal was to increase the number of 9.6V batteries stored within the chassis. The extra plastic parts were stripped to make way for the components that will be fitted on top and to make space for the electrical wiring. I did this by cutting the inside housing and bending the plastic with a heat gun.

After the modifications, the battery capacity was increased to three, two in the midsection and one underneath where the previous stock housing is located.

Drivetrain & Motor Controller

Seen in the picture above, the stock motor controller board was moved up front to clear up some space. The wires leading to the drive motors were lengthened to accommodate the modifications.

Motor Controller

Rather than starting from scratch and building a new motor controller board, why not use what was supplied in the first place? Here the stock controller board has been modified to accept signals from the proposed controlling system. The TAIYO 88-R IC chip that I soldered to only responds by setting the pin low via the controller board ground, see the pinout picture below. That way I can activate the motors to perform Forward Right/Left and Reverse Right/Left from the soldered control wires. I’ll be isolating the control wires from the controlling system by use of an opto-isolator because the ground potentials are different.

Also, be sure to disconnect the antenna and disable the antenna input filter circuit to keep out stray interference. I did this by removing the two capacitors at the input of the antenna. The antenna hole can be seen on the lower right side in the picture below.

Back of the Fast Traxx stock controller board

TAIYO 88-R IC pinout

Drivetrain

Since it was working well the drive system was left stock, other than some minor plastic weld epoxy repair work.

Camera

JBProjects found that the best network camera for this sorta setup was a Panisonic BL-C1A (detailed specs here). The nice things about about it is that it supports low voltage operation, hassle free setup/easy to use, and serves up a streaming url that is perfect to integrate into the basestation software. Just plug it into to the WRT54G router. I paid about $40 US for it on E-bay.

Specifications at-a-glance:

• Color Video
• Video Resolutions – 640 x 480, 320 x 240, 160 x 120
• JPEG image compression & video streaming
• Frame Rates (Max.) – 7.5 fps @ 640 x 480; 15 fps @ 320 x 240; 15 fps @ 160 x 120
• Motion Mode available
• 9VDC at 750 mA operation
• Green light indicator lets you know that you didn’t burn up the controller

(Courtesy, panasonic.com)

Basestation Control

I’ll be using a standard issue Dell laptop with a linksys 54g wireless card as a suitable basestation control center.

Software Interface

Ugh VB! Fine. I’ll use it for now. =)

Wireless Radio

WRT54G Router

Operating system

OpenWRT WhiteRussian v0.9 (Linux) for the WRT54G.

Sofware Contol

Hardware Interface

Rover Microcontroller

Hardware Inferface

(to wrt54g)

Safety features

Schematic & Circuit Board

GPS Tracking Device

GPS-500

Shown previously in the Budget USB Enabled GPS post, this tiny gps unit is perfect for tracking the location of the rover. The gps unit was connected in via the RS-232 chips on the rover microcontroller board and sent to the RX pin of serial port 0 (S0). For now, I was able to Cat the NMEA data output and show it on the screen in real-time.

Power Delivery

Power Consumption Estimations

Battery Packs

Linear Regulators

Camera’s 10V 750mah  linear regulator with three diodes to step down the voltage to around 9v.

Wireless router’s 12v 1.5A linear regulator.

Rover microcontroller 5v 750 mA linear regulator.

Schematic & Circuit Board

Testing, testing, tes..t..ing…

Breadboarding

Systems Integration

Smoke and broken mirrors

Mismatched grounds caused a small fire, I’m okay.

It works!

Making it all fit

For beta, just to proof-of-concept, I didn’t care much how it got there, just as long as it stayed. That’s when good ol’ masking tape came in handy.

Bear with us, this is a work-in-progress project. =)

]]> http://ubermodder.com/fast-traxx-rover/feed/ 7 http://ubermodder.com/inexpensive-bench-top-supply/ http://ubermodder.com/inexpensive-bench-top-supply/#comments Tue, 04 Aug 2009 20:13:41 +0000 Trent http://ubermodder.com/?p=224

PSU Benchtop Supply

If you haven’t built one of these yourself yet, this one here is a real forehead slapper.  Create a cheap benchtop power supply from a standard ATX computer PSU.  In my case I did it completely from stuff I just had lying around.

Difficulty : EASY - SAFETY WARNING, Shock Hazard
Time: 30-40minutes

Most of you reading this have (or know someone who does) an old PSU lying around collecting dust.  The one I used was a 200W dinosaur that I pulled out of some 266Mhz gateway machine that was made in like 1996.  I gave it some new life by pulling together just some parts I had lying around the computer salvage yard in my basement.

Materials:

1 – Old ATX PSU

1 – Automotive Toggle Switch

1 – LED

1 – 330ohm resistor

electrical tape or shrink tubing

Tools:

Soldering Iron

Cordless Drill and drill bits

Super Glue

First thing you need to do is crack open the case and remove the cover.  A quick word on safety.  Even though this is an extremely simple project, some of the components inside the PSU are EXTREMELY dangerous.  It is suggested that you properly discharge the larger capacitors before you begin working on the PSU.  A quick guide on how to do that can be found HERE.  Once you’ve discharged the caps, you need to find a suitable position to mount the Switch and LED. Drill the holes out for your switch and LED be mindful that you need plenty of clearance for the wire to be routed behind them.

Next, on the main board harness, find 2 black Ground wires, the green Power On wire, and one red +5V wire.  Cut them off the clip, and pull them out of the harness and back inside the PSU case .  Pinouts of what the rest of the wires do can be found HERE.

Solder the green power on wire and one of the black ground wires to the toggle switch, and then mount the toggle on the case cover.

Now solder the cathode of the LED to one end of the 330ohm resistor.  We need the resistor to control the current going through the LED.  Solder the other end of the resistor to the Red wire.  now solder the anode of the LED to the black wire.  Insulate with tape or shrink tubing.  Put the LED in your hole and super glue in to place.

Route the wires and replace the cover and you’re done.  Keep in mind that when you get things for cheap they’re not always perfect.  The unit I used in particular does not have exactly the +5V or +12V that the lines are supposed to give.  It is suggested that you incorporate a potentiometer across the +12V and -12V connections allowing giving your an adjustable 24V range to play with.  My suggestion is check your voltage with a DMM before hooking it up to your work.

$5 iphone stereo headset

The iphone 3G is a pretty neat gadget.  One of the problems with a device like this is the headsets can cost a lot if you lose or destroy them.  Instead of paying an arm and a leg for a commercially available stereo headset for your phone, build one yourself where the remote button works and have the ability to use any earbuds for about $5.

Difficulty : EASY
Time: It took longer to write this how-to

Materials:

• 1- 4pin 3.5mm audio jack female (optional)
• 1- 4pin 3.5mm audio jack male
• old cellphone headset or compact microphone with in built button
• ~2ft – 4 conductor enameled wire

Tools:

• soldering iron and solder
• side cutters
• strippers
• shrink tubing and heat gun
• multimeter

Doner head set and 3.5mm 4-pin jacks

The first thing you want to do is cut off the ends on your donor headset and check continuity with your multimeter.  Figure out what wires go where.  You’ll also want to make sure that your button is a momentary contact button.  how the iphone senses that the button is being pushed is the resistance that it normally senses in the mic goes to near zero (i.e. the mic is shorted to ground).

Next you’ll want to wire up the mic.  I had the advantage of having part of an old HTC mogul headset laying around which is already a stereo headset with a mic.  If you don’t have this luxury there are two ways to get your mic wired up.  If you’re the adventurous type you can crack open the mic case and run your 4 conductor wire in to the case.  Otherwise, you can treat the mic like a little dongle off your headphones.  If you’re going to do the dongle I’d suggest tying the dongle to the wire with a couple of zip ties.

inline mic style

dongle mic style

To make the button work properly, solder one end of the button to ground and the other end to the phone side of the mic (button will be in parallel with the microphone).  Many headsets do this already and your doner set might do it this way.  In my case the HTC headset did not so I had to solder the wires together.  Don’t forget to clean the enamel off the wires before you start soldering.  I like to use a solder gun to do this, that way I don’t end up with enamel gook all over the good soldering iron.  Tin the ends up before you try to join them together.

cleaning off the enamel

Now you need to solder on the male and female jacks on the respective ends of the headset.  DO NOT forget to slip the shrink tubing and jack cover on before you begin soldering.  Soldering these ends can be a real pain in the butt, especially pin 2 on the male jack, you don’t want to have to do it twice.  See the pin out chart below for what goes where.

pinouts

The last step is to heat up the shrink tubing with your heat gun and slip the cover over the male 3.5mm audio jack.

shrinking tubing with heat gun

If you did everything right, you can slip a set of earbuds (or headphones) of your choice in and you should get stereo sound.  The button on the mic will not only pick up a phone call it will pause/play your songs on the phone.

Great, you’re done!  Wasn’t that easy?

The finished product

GPS-500 Setup

Looking for a cheap GPS receiver? Look no further than the GPS-500 Microsoft Streets and Trips GPS by Pharos. This tiny unit features a SiRF Star III chipset and most are selling on ebay for just under 10 dollars! This GPS receiver can be interfaced via a RS232 serial link using a MAX232 chip from Maxim IC and a low cost USB to serial converter.

Difficulty : Medium
Time: 1 Hour

GPS-500 Side

GPS-500 Top

After purchasing this GPS receiver, I thought that it would be ready to go, very wrong. In reality the unit needs a special converter cable to interface with a serial port, who has time to buy and wait for that?

Assuming that most devices use 5 volts, I started the very dangerous method of applying power and ground to various pins on the GPS receiver. Once the power was applied correctly a blue led turned on.

Now, I just needed to get the NMEA output data from the GPS receiver. Using a RS232 converter like the MAX232ACPE shown in the schematic below, I connected pin 14 of it to the RX pin of a serial port and listened for data via hyperterminal. Next, I attached a wire to pin 11 of the MAX232ACPE and tried the remaining pins on the GPS receiver.

GPS Test Schematic

Upon finding the TX pin of the GPS receiver, hyperterminal was receiving garbage text because of an incorrectly set baud rate. After some trial and error, the baud rate was found to be 4800bps.

Based on what I have found, the pinouts are as follows below. The unused pins could be RX or some sort of special functionality that the SiRF Star III GPS chipset has to offer.

GPS-500 pinout

Lastly, I added a switch on the output of the GPS’s TX line, a usb to serial converter, and LOTS of hot glue to secure the wires in order to interface with my laptop. The switch was added to shut off the GPS’s TX output from sending data to the computer during the first 5 seconds of powering up. Otherwise, hyperterminal would cease to read from the device.

Finalized GPS Schematic

The SiRF Star III technology is quite remarkable, I was able to acquire 8 GPS satellites on the first floor of a two story house!

GPS Teardown

GPS Laptop Setup

Home-made Instrument Cluster

One way to spice up the appearance of your ride and give it just that much more functionality is to create a custom instrument panel. For most models of vehicle there are several options out there for after market instrument panels. But where’s the fun in that when you can build your own!

In this case I had to build my own from scratch considering I require gauges that will work with a Chevy LT-1 and the vehicle is a 1990 RX7 that originally came from the factory with a 13B rotary engine. Of course a rotary does not have pistons so things like tachometers do not behave the same. There is not a crank position sensor to signal tach pulses, because there is no crankshaft in a rotary.

Originally when the Small Block was put in to the RX7 I modified the resistance values of the factory tach to work very close to correct over most of the range, but as of late it has begun to act up and I’ve decided to switch over to all Autometer Phantom gauges.

Using parts of the original instrument panel and guage pod can be very helpful. I wanted to leave a relatively stock look on the vehicle when you’re looking in from the outside casually so I’m not doing something crazy like building a custom dash out of fiber glass (this is Ubermodder kids, not Unique Whips) but just modifying what Mazda gave me. I started by removing the stock gauge pod from the vehicle, and removing the gauges from the pod.

Hollowed out gauge pod

Next I cut the original gauge bezel out.  When I cut the factory bezel out I left some of it intact as tabs so i can affix my new bezel to it with rivets.

So I have a chopped up gauge pod.  I need to start a new one.  I used a piece of 18 gauge sheet metal for this.  I also looked at other options.  I’ve seen other people use carbon fiber board.  Also a piece of anodized plate aluminum would work fairly well too.  However I settled on steel because its cheap and looks great with paint on it.

I used a set of tin snips to rough the piece in and then used a hand file to hone in the dimensions. I wouldn’t suggest using a hack saw due to the tendency of the metal to warp. This is probably the step where the most time is spent. Getting the fit as tight as possible is very important for the cosmetic appearence. For the layout that I used there is not enough room to put a trim piece in to cover up sloppy fit.

Roughed in steel bezel

Next I found gauge cluster layout that would fit with the space i was given to work with and stenciled it on to the metal with a marker. One thing to keep in mind is that the edges of the gauges are not normally flat and therefore if you stencil the face too closely the gauges will rub against each other when they’re installed. I found that a 1/4″ or so of clearance was enough for a tight yet not too tight fit.

With that piece of sheet metal fitting in snugly, it was time to chop out the holes. Had I been able to get my hands on the properly sized bi-metal hole saws and a good drill press i would have gone that route to cut the holes out. Unfortunently the standard sizes of hole saws don’t match that of my gauge proportions. Thus I again got the dye grinder out and choped X-shaped slices in the gauge holes to rough the shape in, then finished it off with a rotary grinding bit. These holes don’t have to be perfect, yet they need to have a tight fit on the gauges. At this point I also drilled holes out for the pop rivits I will use to affix the bezel and holes for turn signals and high beam lights.

Bezel with holes drilled

Once all the gauges fit properly and I had knocked the rough edges off the piece, I sent it off to the paint shop to get a coat of paint that matched the car’s body color on it. Now there are a lot of other options you could do at this point as well. Powder coating, or anodizing (if you’re using aluminum) would work well too. I would try to stay away from using spray paint due to it’s tendency to scratch easily.

Once It came back from the paint shop I threw in all the parts and it looked like this:

All painted up and guages in

At this point I did a lot of test fitting and measuring to make sure one last time that every thing would fit, especially that there was clearance behind the gauges for everything to be bolted in on the original mounts. Once I confirmed everything fit well, I wired it all up. To do the wiring you’ll need a wiring diagram for you particular year and model. Keep in mind that gauges like Oil pressure sensors will need new sending units put in to the engine block. Also depending on how the Vehicle speed sensor is run out of the car, new wire may need to be ran to the transmission. All of this should be covered in the gauge’s instructions. I used a wire that was 20 gauge stranded, it was probably a little bit overkill but that’s what I had on hand. I soldered all the joints and sealed them with shrink tubing. Using crimp connectors can cause a lot of problems down the road since they tend to loosen up from thermal expansion and contraction (also you’d have an enormous ball of plastic connectors). To connect the pod to the car, I used high quality bullet connectors for the master wire connections. You could solder these joints if you wanted, but if you ever need to get behind the gauges, you’ll have to cut the wire and re-solder.

So all that was left after that was to put it in to the car  and wire up the connectors.  Voala its done!

View from outside the car

Home-made Instrument Cluster installed