R2 Sound System - Rev 3

June 18 2004

Addition Dec 29 2004

Addition Sept 10 2005

I have now gone through several sound systems for my R2 and here is the latest setup. All older versions will still work but as always I can not stand still.


Rev 1 - CD and Switch 16

My first system was a CD player hooked up to a switch 16. In theory by wiring up the switch 16 to the controls of the CD player I could control the CD player by remote. If I memorized where specific sounds were I could play whatever sounds I wanted.

I would be able to burn CDs to whatever sounds I wanted.

In actual fact the Switch 16 was not as positive connection as I thought it would be. Pressing a button on the switch 16 did not always translate to the CD working the way I wanted it to. So it was hard to specifically chose the sound I wanted.

In the end I would use only the play and stop controls and let the CD play. I burnt a CD with sounds that had 30 second gaps in it. So every 30 seconds r2 would make a sound. Not ideal but at least it is some sounds.


Relatively inexpensive way to get sounds

Any sounds can be burnt to CD

Good quality sounds

Instant on


Bad Points

Switch 16 did not work as planned

Maybe slight delay in playing sound since CD has to spool up to playing speed



I used computer speakers that has an auto on function. It powers up only when it receives a signal. I retained the 3 prong plug that goes straight into the CD player. I lucked out and got speakers that pumped out quite a bit of volume compared to other ones I have seen. Not loud enough for a really noisy room but good 90% of the time.


Rev 2 - Laptop & ATI Remote

Wanting a better system I looked into a laptop. I found an ATI remote which connected to the USB port and was radio frequency (RF) instead of Infra Red (IR). The benefits of RF is that I do not need line of site to get the remote to work. This is good if there are a lot of people around R2. RF remotes are not as common as IR ones. The ATI one does a good job. I was able to find a program that would allow me to chose specific song on WinAMP. So I could have 100s of songs/sounds and I can pick any one I want.

You could punch in a number and it would play the track or I could pre-program a button to play a specific sound

A beautiful solution if only there was a quick method to power up the laptop from off


Instant access

100s of songs. Total number dependant on the size of the laptop hard drive

RF so no line of site needed

Bad points

Expensive - need laptop

Long power up time. When powering on you have to wait until everything loaded.

Laptop susceptible to damage?

I have not figured out a remote method to power up laptop.


Rev 3 - Sounds card and 10 channel remote

Here is the latest sound system

Take one ACS CFSound II card ($102US) with a 24 input card ($41.80US)


I put wav files on a CF card and plug this into the unit. It reads the CF card and uses this to play the sounds. With the RS232 port I can directly access over a hundred sounds.

This card also has a few neat features that can be used to animate you droid even more. There is an 8 Input/output card that when triggered will play a sound as well as activate some other function. The standard card comes with one Output but you can get a card with 8 outputs.

For the sound card

I thought one use would be if someone slaps R2s dome. I could wire up a sensitive switch that if the movement if strong enough it could close a switch and play the scream sound. But I would be worried that if a kid discovered this feature they would be slapping R2 all the time

I have kids look inside the Holoeye or lower HP all the time. I could hook up a light switch so that when it senses low light (when someone covers the holoeye) I could have it play a sound

I/O feature

This feature can be used to activate something. For example you could have a specific sound play and then activate the HP to make it move or turn a light on the HP. You could play the âHelp Me Obi-wanâ sound file while lighting the HP


Next is the remote.

Electronic Hobby Kits has a 10 channel RF remote


This is activated with a 4 button key fob. When wired up to the sound card I can play 10 different sounds. With different CF cards I can download a different set of sounds if needed. Being RF it does not need line of site. I have programmed the sounds so the 4 buttons are the most common used. The other combinations of dual button presses will produce other sounds not as commonly used (ie scream or Star Wars theme)


Instant access to sounds

Ability to wire up other sounds to other switches (sensitivity, photo electric, proximity etc)

Ability to power something else when a sound plays. (ie Princess Leia "Help me Obi-Wan..." with the HP light going on.

Key fob can be easily hidden when choosing sounds


Down Site

Slight delay upon power up as CF card is being read (20 second)

Only 10 sound selections possible with current setup

A bit costly for those on a budget


The sound card can be purchased with it installed in a box already. Since I knew I had the remote to put in I purchased the sound card without the box (saved $20US). I thought about going to an electronics store and buying a box but that could have been expensive so I went to the local hardware store to see if there was something that I could purchase cheaply. Something like a food container. It turns out I found a First Aid kit that was perfect. It was a nice sturdy plastic box with an opening lid. There was also a rubber seal around it so it was sort of water proof.

To mount the two boards I disassembled an old non-working computer and used the stand off used to mount the mother board. I planned to drill holes into the box and then put nuts on the back side. It turns out the standoffs did not have long enough threads so I drilled the holes in the box slightly smaller and threaded in the inserts. To make them stronger I scuffed up the box surface and put down some epoxy for added strength

Sound cards

Note that this is only one sound card and I am sure there are others out there that may be cheaper of have other features but I am reporting on my setup because I have assembled and tested it and I can report that it does work.


CF cards

Things that make you go ARGH! I wasted about 3 hours trying to get the setup to work. It all had to do with the CF card. Lexar CF cards do not work with this sound card. I have warned you now. Also make note of the MHZ and bit rates of the wav files.

Everything powered by 12VDC. I tested this wired up system with a transformer and everything is fine. My gel cells are all 12VDC and this system is perfect voltage.


The mess of stuff during the building process. Yes it looks terrible but I know where everything is. That is a Polar Lights NX-01 on the right


Not many tools needed. Soldering gun, wire, wire cutter, wire stripper, solder, flux. It looks complex but everything was actually easy (I think)




All wired up. Once tied off the the wires will look neater


Here is the first aid box I bought to hold everything. Those labels are sure hard to get off. Don't want someone needing a bandage and finding wires


The inside of the box with the motherboard mounts taken from a garbage computer. Glued with epoxy for added strength


Boards mounted into box. Isn't that perty?


Another view of the box with the remote on the lid


Close up of the remote and the 4 buttons. using various combinations I can get 10 separate channels


Top down view


R2 Sound system

Modified Dec 29 2004


Here is an extra section with a bit more detail about my sound system


This is the system I am using for my droid. There are other systems and methods of making your droid produce noise but I am going to concentrate on what I have working


Well one of the cheaper options for a remote is from ebay

There are "12ch RF remote" that have been going for around $25US. This is a cheap way to get a remote system for your droid. This can be used on functions for your droid or to activate instant sounds on your droid.


Before these remotes became available on ebay I found a remote on the internet



I got the 10 channel remote



The one off ebay is a lot cheaper. The benefit of the above system is the roaming security channel. Not terrible important for R2ing but nice For the price go with the 12ch one



For the sound car I am using, start off here




I am not using an enclosure and I did not buy the wall transformer. $102-5-20


Later on I purchased an enclosure that would be ale to fit in the remote cards also


I did get the CFSound II Contact Sense 24 $41.80


And the CFSound II 20 Watt Stereo Amplifier $24.95. The amplifier is needed only if you plan to power the speakers directly. If you have amplified speakers this unit may not be needed. In my setup my amplified speakers were not enough and I had to purchase the amplifier later on and install it on the board.


The other items you will need is a CF card reader/writer and a CF card. Note that the Lexar brand of CF will not work.


This will be a step by step procedure to test the system as we go along to make sure things work before going to the next step.


Once you have all the items I suggest starting with e CF card. Follow the instructions to prepare the CF card and to name the songs as needed.


We will run a quick test to make sure the sound board and the format of the sound card files are correct.


Plug the CF card into the sounds board. Wire up some temporary leads to the speaker outputs. Wire up some temporary wires to the first contact


Apply power to the sound board. If done properly there should be a green led flashing. This means the files are being loaded into the sounds board. When the led is a constant green then the files are all loaded up and the sound card is ready to go. The amount of time to load up the files depends on how many sound files you have on the CF card.


If the LED is red then there is a problem with the initialization file or the name of the files. Consult your manual to fix this problem.


If the Led does not light up then your power polarity may be reversed.


If the LED is a constant green we can then check to make sure the system works.


Join the 2 wires from the first contact. You should get sound out of the speakers. If no sound comes out try the second contact. No sound can mean that you have not correctly named the sound file properly and there is no sound for the first contact.


If sound comes out continue for the rest of the contact to make sure each one produces noise.


So now we know the sound card work.


Next we will check to make sure the 12ch remote works.


Apply power to the remote. If the polarity is right when you press a button on the remote you should hear a relay click. A red led will light on the remote when you push the button. Try all the buttons and there should be a click for each one. If there are no clicks the power polarity may be wrong. If not all relays click there may be a loose connection on your receiver board that may need soldering.



He next step is to wire up each relay to the sound board. Each relay comes with 3 contacts. One is a common contact while one is normally closed and the other one is normally open. You want to wire up the wires to the normally open contact. After each cannel is wired up you can then apply power to the entire unit and test.

 Sept 10 2005

So I did switch out the 10ch remote for a 12ch remote. I like the fact that I can push one button to activate a sound instead of a combination of buttons. Although this remote does not have a roaming code I do not see it as a problem. Although I am in theory using only half the capability of the CF II sound card I find that 12 specific sounds are enough. Another good feature of the CFII sound card is that you can sequence one channel. I have set up channel 12 on my remote to play various songs. Some are Star Wars and some are not. I could have as many song/sounds on that one channel as my Flash card memory will allow.

Currently the CFII card does not allow this sequencing to work on all channels. You have to chose one for the sequencing. We are trying to get the manufacturer to change the software to allow the CFII to sequence every channel. If this were available you could set up several channels to reflect certain moods. Channel 1 can all be happy sounds, Channel 2 can all be sad sounds. So in theory you could have 3-4 emotions and this would free up the other channels of the remote for other stuff. I recommend everyone who has the CFII card to email the manufacturer and say you have the CFII board for your R2 and was wondering if they could update the software to allow multi channel sequencing.






If you want to build your own R2 go here --http://groups.yahoo.com/group/r2builders

Email me ask@interlog.com