Posts Tagged ‘halo’

DIY Ammo Counter

Monday, December 21st, 2015

Do you need an ammo counter circuit for your project and are bummed that you have to wait for a spot in my build queue to open up?  Fret not, here is a step by step how to make one from scratch!

In this guide, I will detail how to build your own ammo counter for ~$25 and with only minimal soldering experience.




You can use other arduinos or switch and display choices.  The linked ones were chosen for number of pins and size.  This project uses 16 IO pins from the arduino and the trinket is the smallest arduino that can be programmed over usb.

If you get a different display, it must have the following traits:

  • Common Cathode, the common pin is ground (do not want Common Anode)
  • Two Single Digit 7 segment displays, with 10 pins on the back EACH.
    – OR –
  • One Dual Digit 7 segment display that is non-multiplexed, with 18-20 pins on the back (multiplexed only has ~10 pins)

Wire Display to Arduino:

Get out your solder iron, wire strippers, and some note paper.

  • Wire display digits 1 and 2 as shown below, diagram only shows one digit for simplicity.
    • The common pin (CC) goes to ground.
    • The period (DP) can be left unwired.
    • Each segment is wired to a unique pin on the arduino, can use any arduino pin marked as D or A.
    • The exact pins wired to are important, write them down for later.  To run the software without modification, use the default pinout table below.
    • Diagram shows resistors between the display and the arduino.  When using the 3.3 volt version of the arduino trinket, no resistors are needed.




Default Arduino Pinout

Arduino Trinket I/O Signal Type Name
3 ~3 O Display Output Digit 1, Segment E
4 4 O Display Output Digit 1, Segment D
5 ~5 O Display Output Digit 1, Segment C
6 ~6 O Display Output Digit 2, Segment E
8 8 O Display Output Digit 2, Segment D
9 ~9 O Display Output Digit 2, Segment C
10 ~10 O Display Output Digit 2, Segment B
11 ~11 O Display Output Digit 2, Segment A
12 12 I Switch Input Fire Switch
13 13 I LED Output LED
14 A0 O Display Output Digit 2, Segment F
15 A1 O Display Output Digit 2, Segment G
16 A2 O Display Output Digit 1, Segment B
17 A3 O Display Output Digit 1, Segment A
18 A4 O Display Output Digit 1, Segment F
19 A5 O Display Output Digit 1, Segment G
RST RST I Switch Input Reload Switch

Finish Wiring Assembly:

  • Wire the fire switch to a digital pin and ground.
  • Wire the reload switch to the reset pin (RST) and ground
  • Wire in the trinket to a 3.3 – 5 volt battery pack, blue and white color displays requires minimum of 3.2 volts.

Program Software:

You will need a micro usb cable.  No batteries needed yet, the trinket is powered by the usb for now.

Source Code:

  1. Follow the getting started guide from codebender to setup the website to talk to your arduino trinket, choose Adafruit Pro Trinket 3V USB when asked
  2. Open source code link
  3. Click Run on Arduino
    • If you get the error message, make sure to press the button on the Trinket to activate the bootloader before trying again.

Optional Software Changes

With the source code open on the website, find and click the edit button to make changes to the software.  After you have made changes, click Verify Code and resolve any issues, proceed to ‘Run on Arduino’ when the website indicates ‘Verification successful!’

  1. If you did not use the default pinout, you must update the pinMap list with where you wired each display segment. Use the pin numbers you wrote down
  2. If you want to use a different starting ammo count or firing types, scroll down and update ‘Starting Values’.
    • shotmode can be set to CONT for full auto or BURST for semi auto
    • burst_value is the number of ammo shot in each burst, default is 1.
    • counter_value is the starting ammo value.


  • shotmode = BURST; burst_value = 1; counter_value = 99; is used for paintball or nerf
  • shotmode = CONT; burst_value = 1; counter_value = 60; is used to match a Halo AR MA5B
  • shotmode = BURST; burst_value = 3; counter_value = 36; is used to match a Halo BR55


On startup, you will see the starting count of MODE1. Press the fire button and the number will go down 1 tick until 0.  The LED (pin 13) goes dark when the counter reads 00.
Press the reload button and the display will go blank, and then reset to the starting count.

Hold the fire button down while pressing reset, this will change between modes. Display will report the mode number as F1, F2, F3, and so on.

Feel free to play with the software further to tweak the features to your liking. Have fun :)


Energy Sword 2015

Tuesday, May 5th, 2015

This is the new Energy Sword for 2015. Featuring dynamic and reactive lighting, motion activated sound effects, and an internal rechargeable battery. Videos on the bottom of this post show off the lighting and sound effects. I built my original energy sword design with the help of Sean Bradely in 2009.  This work was expanded by Joshua Kane in 2013 / 2014.  I took Joshua’s work to the next level with multiple animation modes with reactive and multi fade lighting. Kudos for the sculpting and paint job still goes to Sean Bradely.

Energy Sword Action Pose

Note: I abandoned the custom circuit that I detailed in a previous post and instead went with inexpensive circuit modules from Adafruit and Sparkfun.

Electronics Part List

Sword Usage

  • While OFF
    • Press button to activate
    • Hold button to enter color selection mode > Press to cycle color modes > Hold to save selection
      • Energy
      • Fire
      • Water
      • Rainbow
  • While ON
    • Press button to extinguish.
    • Hold button to enter animation selection mode > Press to cycle animation modes > Hold to save selection
      • No extra animation
      • Flicker on, Comet Off
      • Flicker off, Comet On
      • Flicker on, Comet On

Note: Additional animations are ignored in Rainbow Color mode


Ammo Counter Assembly Instructions

Friday, February 20th, 2015

Counter Assembly

DIY assembly guide for the ammo counter.  If you ordered an unassembled circuit kit, this is the instruction page for you.

Assembly order is from the center outward to minimize solder bridges.  Keep some solder removal braid handy to remove any bridges between pads.


  1. Install the IC, making sure to orient with pin1 indication on the PCB
  2. Install the three resistors.
    1. 2x 10k on the bottom
    2. 100 ohm on the top
  3. Install the LEDs and bend into position to match your install location.
    1. LED on top center position (unmarked)
    2. LED on bottom marked position.

Note: The LED polarity is not marked on the board. See the wiring section for additional help.
You can also look at the copper traces that connect to the LED socket.  The ground is connected in multiple points.  The positive is connected to a single trace.

  1. Install the capacitor to the top of the PCB.



  1. Install the diode, leave the leads long and do not solder yet.
  2. Install the display but do not solder yet.  Orient the same as the graphic 8.8.
  3. Bend the diode down and out of the way of the display.
  4. Solder the display and diode.


||  +-----+      +-----+   ||
||  |     |      |     |   ||
||  |     |      |     |   ||
||  +-----+      +-----+   ||
||  |     |      |     |   ||
||  |     |      |     |   ||
||  +-----+ .    +-----+ . ||
|1 2   3 4   5  -====-  8 9 |

|           11 10           |
| .  .  .  .  .  .  .  .  . |
|    =.1uF=          =100=  |
|\   ATTINY2313            ||
|/                         ||
|  =10k=             =10k=  |
| .  .  .  .  .  .  .  .  . |
|9 8   7 6    5    4 3   2 1|

Signal Name Location Ground
FIRE SWITCH 1. Fire Signal 2. Ground
POWER 6. Battery + 7. Ground
RELOAD SWITCH 9. Reset Signal 8. Ground
Top LED (Always ON) 10. LED + 11. Ground
Muzzle Flash 5. FX


Note: Power socket overlaps with the diode.  Be careful not to short.



  1. After connecting power, you should see the display light up with the current clip size.
  2. Press the fire button to decrement the ammo count.
  3. Press the reload button to reset the count.
  4. When the count reaches zero, the Ammo Available LED will turn off.
  5. Additional fire modes are accessed by holding the fire button while pressing reset.  Display will read F1, F2, F3 to indicate the selected fire mode and clip size.  Release the fire button to save your selection.


PCB Trace Reference

This section is useful for modification and troubleshooting.  You can see where the trace wires go on the pcb.


Counter_3.11 FRONT_PCB


Counter_3.11 BACK_PCB

Reference Pictures

Additional pictures are on flickr.


Final assembly.  Shows placement of diode below the display.

Counter Assembly


Display is not soldered down yet.  LED leads bent to match install positions. Shows orientation of chip.

Top resistor pictured is 150 ohm, kit includes 100 ohm.


Counter Assembly


Orientation of display to front

Counter Assembly

New Beginnings – Sword 2014

Thursday, January 16th, 2014

Announcing a new sword electronics design and a partnership.

I have been working alone the past years on an updated energy sword circuit design.  Something that would allow me finer control of the LEDs without the burden of soldering the old massive LED arrays.  Details of my 2009 sword design.

Joshua Kane had been working independently on his own sword controller circuit, build completely from arduino modules.  You can see a write-up of his original project here: Stunning Halo 3 Costumes and Energy Sword

The outer shell of our both swords were made by an amazing sculptor named Sean Bradley.  It was through Sean that Josh and I met each other; and beginning last fall, we began working closely to bring an arduino based sword controller to life as a kit.

New Features

  • Motion activated Sound Effects
  • Motion activated Lighting Effects
  • Lighting Animations: Extend, Detract, Pulsate, Flicker, Clash
  • LED arrays are off-the-shelf LED Strips of varying prices and pixel densities from Adafruit.
  • HD MP3 sound effects (and LOUD too, thanks to the built-in amplifier plus speaker)
  • Lastly, this circuit is USB programmable using the Arduino Software as a Leonardo board.


Preview of the 2014 sword circuit


Another thing to note on this circuit board is the accelerometer chip on the back.  Wow, is that guy tiny!  Putting my hot air rework station to good use to get that guy soldered.


New Sound Options in the Store

Friday, May 18th, 2012

I often get asked about offering sound functionality in my prop kits that I sell. As demonstrated by my energy sword design I had a solution for sound, but it was not a solution that I could extend to my cheaper kits. Sound is hard, not just hard but expensive. Till now.

Introducing the 300 second USB recording module from <a href=””></a>. I have fully inregrated their sound module into the Backlit Ammo Counter offered in my store via an adapter circuit. The sound module can also be used stand alone, but you do not need me for that, go buy one from Electronics123! They are good folks.

The need for the Adapter Circuit

The sound quality offered by this sound module hits a sweet spot in cost to performance. In addition, the level of programmability at this price level is unmatched. The only function that cannot be programmed is to switch between two sounds based on a second input. I want to hear the firing sounds only when ammo is available, and the dry fire sounds only when ammo is not available. This is where the adapter circuit comes in. The backlit ammo counter already reports via the bottom LED if ammo is available or not. The adapter circuit takes the signal from that LED and the FIRE switch and performs some logic to decide which sound to play.

Is that simple, now the sound module gives sound effects exactly as expected for a fully automated weapon. Options for semi-automatic are in progress.

Secondary Announcement

New configuration options for the Ammo Counter in the store! Custom rates of fire. Prior to now all Fully-Automatic Ammo Counters have had the same fire rate of 5000 rounds per minute. Which is crazy fast for the most popular selection, the Halo AR having a fire rate of 600rpm.

Cortana Prop Circuit

Tuesday, May 3rd, 2011

Project is a cortana prop. Partnered with James Hodson and friends to complete. My portion is complete. Have a circuit board here that is the size and shape of the Halo Data Crystal (the thing that can contain an AI such as Cortana).

What is a Data Crystal Chip? Please see the Halo Wiki [].

Feature set:

  • Circuit board is designed to look like a naked “cortana” data chip.
  • Board can be placed in a molded outer shell to be more accurate. More details to come.
  • Compatible with multiple power sources depending on final usage:
    • LiPo cell (internal shell design)
    • Alkaline (wired to slot connector)
    • USB (wired to slot connector)
  • Can be plugged into a matching slot connector for power up
  • Slot connector can be used to power up other suit lights. Inserting the board into the slot is like flipping a switch on.
  • Micro-controller chip is on the circuit board to animate the lights.

Source Code



Working hard on the next stage of the project: Make a plastic shell that houses the circuit and a battery (team jlhR2).
Link to post: [405th Forum]

Video demo of using the cortana chip as a switch


PCB order is in, could mass produce a few right now if I wanted.
Link to post: [405th Forum]


First prototype is fully assembled, ready to proceed to stage 3 on the schedule.
Link to post: [405th Forum]


A nice explanation of all that the cortana board can do.
Link to post: [405th Forum]


First few revisions of the circuit board have been assembled and tested. Slot connector works great~! I ran out of those tiny smd LEDs and ordered some more. Will get one completely assembled later this week.
Link to post: [405th Forum]

Bringing in the latest pictures and videos to page 1.


I am still working on a final draft of the main board design, but here is the gist of what it will do and look like: First, the size is tiny. The thing is as small as the real deal, 1.00×1.85 inches (25×47 mm).

JlhR2 and I are still working on a pep template / mold that will go over the top.

Guide: Weapon Counter Display Overlay

Monday, August 9th, 2010

Took a lot of trial and error, but I think I came up with a method to make a display overlay that I can be proud of.  Thanks for the help James Hodson(jlhR2).

Click More Info for the full guide.

The overlay is meant to go on top of my ammo counters, but also looks good when used alone with a light behind it.  The overlay is made of several transparency sheets layered atop one another plus a sheet of tracing paper toact as a diffuser.  Could probably substitute tissue paper.

The image files to print out are below. You will need to re-size the images to fit your weapon before printing.  If printing at home, be sure to buy transparency sheets meant for ink-jet printing and not laser printing.Ink-jet printable transparency sheets have a rough surface to print onto.

I find my photo printers T-Shirt Transfer mode gives the best print out.  It takes some trial and error, but set the Print Quality to high for best results.

Halo Reach

Click Picture to download full size

Halo General Purpose – James Hodson (jlhR2)

Download full size here:

There will be four layers, from bottom to top there is the tracing paper,two black transparencies, and the color transparency.

The tracing paper and the black transparencies need to be cut so the numbercan shine through (xacto knife).  If not using an ammo counter circuit, youmay cut in whatever number you like.

DO NOT cut the color layer transparency.  This is what colors any light shining through to the proper hue.  It also makes photographs when unlit look amazing.

Tip: I first cut a piece of paper the size of the hole I wanted then taped it down so I could have something to trace with the knife.

Below are pictures of building up the different layers. In these photos onlya single layer of black is used.  You can see that the light gets through a bit in areas that are supposed to be black.  This is why we use two layers ofblack.

Clear tape is used to hold the layers together and keep them aligned.

Have fun~!

DIY Recoil Action

Wednesday, June 9th, 2010

Goal here to add the sensation of recoil to a prop rifle gun.  I have seen it done with compressed air and motor pistons, but neither are easily synchronized with electronics and capable of rapid firings for full auto fire.  Leaves me with the third option of using a solenoid.  To fire a solenoid with enough furiosity to kick the gun into your shoulder involves some serious power requirements.

I did a dry run yesterday and came up with this circuit.  The solenoid is rated 12-24V and 3 lbs force.  Using the circuit below it was weak at 18V, fully actuated at 27V, and actually had some kick at 36V.  I am not sure I want to take it higher.


View Full Size

The next step is to design a circuit to use a lower battery voltage. Three C cells should be sufficient. The 4.5V from the battery would be stepped up and charged across the capacitor. The control circuit would be connected to the solenoid circuit through a optoisolator and a mosfet.

Presenting the Halo Energy Sword~!

Friday, November 6th, 2009

Full Sword Lit

I knew what I wanted to do was design a circuit that would be similar in function to the star wars sabers that fans build. That meant animated lights running the length of the twin blades, an accelerometer to gather motion data, and sound playback for startup and swing sounds.

What I ended up doing was designing a circuit around an ATMEGA32 controller chip.

Hit more info for details.

This is a summary page, additional notes are on the forum.

Original Project Page

Full Sword Lit


I knew what I wanted to do was design a circuit that would be similar in function to the star wars sabers that fans build. That meant animated lights running the length of the twin blades, an accelerometer to gather motion data, and sound playback for startup and swing sounds.

Full Sword NonLit

What I ended up doing was designing a circuit around an ATMEGA32 controller chip. The ATMEGA32 offered me everything I needed at the time, which was serial communication and analog in/out. There was also the benefit that I am familiar with this chip and know it’s documentation well.

Tech – Lights

The lights consist of 66 color changing blue/red LEDs. The lights are connected to the ATMEGA32 via 5 digital outputs and 2 analog outputs. Blade Corner Close up LitThe 5 digital outputs control the ignite and extinguish animations of the blue LEDs, while an analog output controls the red via PWM.
A unique wiring is used for the color changing LEDs. Bicolor LEDs have 3 leads, a common lead, then one for each color. The normal wiring method is to connect resisters to each color’s lead. I used a single resister on the common lead which makes it impossible to light both colors at the same time (forward voltages are different for each color). But by using the microcontroller’s PWM function, it is possible to make it perceived that both are lit at the same time. Playing with the frequency of the PWM on the red, I found the sweet spot where the red fades up and the blue fades down. This gave the appearance that both were lit at the same time for a purple glow.
LED blade constructionThe effect is set to fade in and out with a timing that matches the barely audible hum that the in game energy sword produces. On top of the fade effect, there is also a flicker effect that is controlled by the raw output of the analog accelerometer.
For a while I left the PWM on during sound playback, the blade had a neat “lock-on” effect that would turn the blade solid red during a swing. However, the PWM created an annoying feedback on the nearby audio amplifier. So now the sword is solid blue during a swing.

Magifier on Accelerometer

Tech – Motion

The motion chip is an ADXL203 dual axis accelerometer. At first I threw out the idea of an accelerometer because of the surface mount soldering that is required, but later found surface mount soldering by hand is attainable. There are some good tutorials on Sparkfun.
This accelerometer has an analog output (force = voltage level) and is connected to A2D inputs on the ATMEGA32. A programming loop monitors the input then if it detects sufficient motion, the program will fire up the sound subroutines. Motions that do not have sufficient motion for a swing are passed to the lighting functions. The raw data from the accelerometer is given directly to the PWM routines and added to the fade value. Since low motion analog data is susceptible to noise, this gives the appearance of the lights flickering in a truly random effect. This also gives the user the impression that they are in control of the flicker. Slowly waving the sword around gives a unique flicker effect.

VMUSIC2 connected to Controller circuit

Tech – Sound

The sounds were recorded from in game and saved as MP3s. Some work was done in an audio studio to clean up the sounds for playback. At the heart of my circuit is the Vinculum VMUSIC2 MP3 player. This sound module has come to be known to be the best sound effect solution for prop makers. It has a USB port to read a USB memory drive and a serial wire so it can be controlled by your own microcontroller. It can play both MP3 and WAV file types with full bit rate of the MP3.
The only down side of the VMUSIC module is the size. It measures 2.5″x1.5″ which could be considered small, but is difficult to fit into the handle of my prop.
I also considered writing my own playback program or using sound recording chips. Neither of them could compare with the playback audio quality that the VMUSIC module provides.

Tech – Amp

The audio amplifier was added as an afterthought and it shows in the design. This is one area that screams improvement needed.
The current solution is a AN7513 1W audio amp chip. This is a small IC that can directly power a small speaker.
The problem is an issue of both volume and sound distortion. The amp is capable of driving the speaker kinda loud, but at volumes louder than 50%, distortion becomes apparent. This limits the speaker volume to household venues.

As an alternative, I added a headphone jack to the design. An wearable small amplifier is connected for usage in noisier locations. Because the headphone output is directly from the MP3 player, it can reliably be amplified to very loud volumes.


To ensure the highest quality prop I teamed up with an individual named Sean Bradely. Sean is best known for featuring his previous halo energy sword that he built. His previous sword consisted of a molded handle, flat plexi blades, and glowing EL wire. It was regarded as the most accurate fan made prop energy sword in existence.
I had a mostly functioning circuit when Sean approached me. We decided that we were working toward the same goal and a partnership would allow us to use the best of both our talents to achieve an even more accurate prop.
He had been in the process of designing a new energy sword for quite some time. For the new sword he would have dimensional blades instead of being flat. In this cavity he planned to insert LED rails to maximize the light given off by the blade. My circuit would be perfect for him and his blade and handle molds would be perfect for me.

Sean's Vacuuformer in action

Vacuformer & Blades

One of the tools to create the dimensional blades was a vacuuformer machine. It was assembled by Sean for this and other projects. I won’t go into it much, but it is an amazing tool to form plastic. More info.

The blades were created on this machine around a wooden buck that Sean cut and sanded into the shape of the blade.

Handle close up assembled

The Handle

The handle is made from an impact resistance resin and was sculpted by Sean. It houses the circuits and has the structural support for attaching the blades.


Handle lighting. This was simply a matter of size and time constraints. We wanted to add lighting to the handle and I had designed pins on the circuit to control this lighting. The idea was that the lighting would be bicolor blue white LEDs wired similar to the way that the blue red LEDs were wired. A mix of LEDs directly on the surface and fiber optics for pinpoints of light. The circuit could even blink or fade the handle lights in a pattern to reflect the MP3 player status. Problem came down to fitting it inside the handle along with everything else tightly packed in there.

Buy a Pager MotorVibration Feedback. Add a pager vibrator motor inside the handle. The motor would be connected to the same PWM signal sent to the blade lights. This vibration would give the sword the missing “hum” effect. The PWM signal is sent in parallel from two controller pins to two driver pins, allowing the circuit to control two devices with the same signal.

Halo Energy Sword

Tuesday, March 24th, 2009

If you read about that sort of thing, you may remember last fall Master Replicas announced a Halo Energy Sword that would feature similar functions as their ForceFX Lightsabers (powerup/down sounds, motion activated sound, animated lights). The promised release date was the holiday season 2008.
There is another company that makes realistic Halo toys, this is the same company that made a plasma pistol and plasma rifle that are superb. They also announced an energy sword in 2007 with a 2008 release.
Here we are in 2009 with no product from either company. I had to do some major digging to learn both these products were canceled and will never be released. Killed for either licensing or safety concerns.

Based on the demo videos released by Master Replicas, it seems possible for me to create my own prop with similar capabilities. Hit more info for details.

Update: August 2009 – See completed project details.

This project is fairly large for me and needs to be broken down.

Modeling and Plastic Molding

Most of the Halo models are freely available and have even been converted into a format that can be printed out. Ready to be cut, folded, and glued into a 3d shape. I plan to adapt this process to recreate the sword’s handle. So far, I have the blade handle shape created and I filled it with expanding insulated foam for strength (paper is not strong).

The next step is to cut this model in half and place on a vacuuform machine (which I don’t have). The resulting plastic shape will be glued or screwed together to create a hollow plastic handle (to house the electronics) that is durable and ready to be painted. There are plans available online for home vacuuform machines that can be built for less than $50 and use a shopvac.

Lights and Acrylic

I need to experiment with some scale arcylic pieces to determine the best method of lighting an acrylic blade, but the goal is to animate some LEDs that illuminate the blade so that the blade will appear to extend and retract.

Diffuser Options
The acrylic has a fiber optic like property when light shines near the edge, the light will bounce around inside of the arcylic until it finds an imperfection to illuminate. A diffuser is used to catch the light.

  1. Sanding the acrylic, will give the acrylic a frosted look.
  2. White adhesive laminate, this is best suited for a multi layered acrylic that is lighted internally

LED Placement Options

  1. A row of LEDs on the interior or exterior edge or both. The LEDs can be covered by a strip of black or white tape. May create “hot” spots along the edges.
  2. An array of LEDs sandwiched between acrylic on either side. Will use hundreds of LEDs and give the most even light.

Whatever I end up doing, the LEDs will be animated. I have a circuit in mind that will do the extend effect very nice, but I am also looking into a microcontroller (depends how the sound effects tests go). As far as I can tell, I will be the first hobbiest to attempt something like this for a Halo prop.

Sound Effects

Besides the lights, this is the most interesting part of the project and is fast becomming the most difficult. I have seen on various forums people harvasting the sound board from electronic sword toys and reusing them for this purpose. I was unable to find any local stores that sold appropriate electronic toy swords. I can find several online but refuse to buy anything before I use it in hand, so I know the light patterns and sounds it will make (don’t want my halo prop making pirate shouts, haR!).

My next option is compiling my own sound effects and playing them back in sequence. This is a lot easier said then done. The actual sounds can not be dumped from the game only recorded while it is running. The best quality sounds I have found are actually from that MR demo video. I plan to record this to some .wav files for the sounds they demonstrated.

As far as playing them back, that is an interesting request. I have a few options including MP3 players, voice chips, and microcontrollers. An MP3 player would be too slow and would have limited playback options, similar story with the voice chip. That is why I am leaning toward a microcontroller. A microcontroller could be loaded with converted wav files and play them back at a sample rate, it could also be used as a substitute for the light circuit and give access to more animation patterns.

The problem with using a microcontroller is more an issue of experience with sound playback. I’ve only done it once before on an 8085, which I don’t have. What I do have is a dev board left over from my college days for an ATMEGA32 chip. There is a great website available for enthusiests of the atmel microcontroller manufacturer and the free software suite, AVRstudio. The website is AVR Freaks and after doing some searching I found some free source for playback of converted wav files. The assembly source is for a different processor, but checking the spec sheets, they are not only compatible, but my chip offers more features and four times more flash memory (32kB vs 8kB for more sound clip storage).

To bad for me, before I left college I accidently erased my serial bootloader. So now I need an ISP programmer ($40). While I’m at it, I might as well also purchase some extra crystals and power transitors so I can build up a stripped down dev board for a prototype circuit. Here is an ordered list of the planned evolution of my program.

  1. Get the sample code working playing back the sample wav file
  2. Get the sample code to playback my own wav file
  3. Call the assembly sample code from a c coded main loop
  4. Playback two wav files back to back
  5. Playback a wav file in a loop
  6. Playback starts on button press, playback stops on button release
  7. Put it all together: Wait for button press, playback powerup sound, playback on sound in loop, wait for button release, playback powerdown sound, wait for button press.
  8. Add timer interrupt to control LED animations

Motion Sensors

I am not really sure, what I will do here. This is more of a future development. I have seen motion sensors before, they consist of a week spring surrounded by metal, movement causes the spring to contact the metal sides. I could use something like this and set an interrupt to triggure additional sound effects (swoosh, swish).

Some other options, tilt switches and accelerometers. I don’t think a tilt switch is what I am looking for, in the tilted position, the switch is always one.
The accelerometer has some technical hiccups. It will detect motion very nicely on all 3 axis and the cheaper models are sensitive to small motions (less than 3G). The problems come in that this is an analog device and to be cost effective, only is available in surface mount packages. The analog side can be handled by the sound microcontroller and the ADC inputs, but the surface mount… that will need some more thought.

Battery Format

Probably a 9V for now, may expand to a recharchable NiMH or an impossibly small lithium poly.

Current Progress

Current progress and project notes can be found on my forum.