I feel like I’m on the home stretch getting R2 back together. Tonight I worked on the electronics a bit more.

I plan on re-install the same three 12V 7Ah batteries. However, when the skins go on it’s going to be hard to charge them. So I’ve devised a simple circuit using some automotive relays to allow me to isolate them from the main electronics with a single switch, and charge from an external plug that will run to my Vector Charger.

I wanted to mimic something similar to how Luke charges R2 on Dagobah. The original plug used is some sort of stereo audio jack, but in real life it would almost certainly short when inserted, so I needed to find an alternative.

After a lot of browsing various electronic and automotive stores I’ve decided to use a 12V car accessory plug and socket for bunch of reasons –

• They can easily handle the 10-15A the batteries will pull when charging,
• It’s hard to short the system when inserting it, even if everything is live,
• If someone was to accidentally plug him into something unexpected – I’d rather it be a 12V device which is almost guaranteed with this type of plug. I couldn’t say the same if I’d gone with some other type of high-voltage plug,
• Replacement parts are easy to find if I ever need to make up a new charging cable,
• Theoretically I could plug-in and charge or run other 12V devices off of R2.

I’m going to install the charging port in the same spot as seen in ESB, and I need to make a shelf to hold everything as there’s no frame behind the hole. I cut a curved piece of aluminum that would become the shelf.

I then bent an angle in it to secure it to the new speaker bracket I made a few days ago.

Everything is held in place with just two 8-32 screws

Originally I was going to use a heavy duty DPDT toggle switch to isolate the batteries

But I had problems finding a suitable switch that would work. The one shown above was to really clunky, hard to toggle and not quite heavy duty enough to handle the potential load the drive motors would pull from the battery. So I opted to use a much smaller switch that would toggle the high load through a few standard 30/40A automotive relays. I’ll probably end up replacing these with 60A relays when I get a chance.

To mount the smaller switch I cut a small piece of acrylic and drilled a few holes that would attach it to the 12V socket plug.

I then heated it up for a few seconds to bend it into shape

I also added a status LED so that I’d know for sure when R2 is switch on

Here’s a shot of the back of the automotive relays that will do the switching. I could have probably just used one and just isolated the positive line, but I decided to play it safe and use a second to switch/isolate the ground line as well.

I’ve just bolted them below the support bracket using the same screws that holds the 12V car socket in place.

This is the setup with all the wiring in place.

When the light is green R2 is on, and the charging port is disabled/isolated from the batteries

When the light is off the charging port is live and connected to the batteries. All electronics in R2 are off and I can safely plug in the charging cable which will glow red to show it’s connected to the batteries.

At some point I may also add some red LEDs inside R2 to mimic what’s seen in the movie.

All that remains is the wiring diagram. This is the hand-draw one I worked from, but I’ll try and come back later and clean it up and verify that it matches my final configuration.

Again note – I’m not an electrical engineer so please double check everything if you’re going to try and implement what I’ve done.

This has got to be one of the best R2 videos on Youtube ever!

Now to figure out what the song is so I can put it in my sound system 🙂

I got my new 4″ speakers mounted in the frame today. I made some simple brackets that bolt onto the side of the supports for the front vents.

I started off with a long length of 1-1/2″ x 1/8″ L shaped extruded aluminum. I cut off two 8″ lengths that would become the side brackets.

The brackets will wrap around the side of the front vent supports, with the speakers bolted to the back.

I drilled 4 holes in each, two larger one’s to allow me access to the screws holding the vents in place, then two more to bolt the new support on.

I then cut away a fair amount of the aluminum to allow the speaker to poke through.

Next I had to tap a bunch of holes to attach the speakers – I hate tapping holes

I tend to do things in small step, for example I fitted the first speaker, tested everything then went back and drilled, taped and fitted the second. All to often I fail if I try do too much at the same time to cut corners.

Here’s the two speakers installed and the top vent surround in place. I’m hoping to use some rare earth magnets to secure the blue surround to the frame.

I’m still concerned that the front vents will block too much sound, so I’m tempted to move one of the speakers into the skirt to bounce sound of the floor.

As promise here’s the demo video of the new CF-III setup. Sorry it’s so long.

P.S. Don’t forget the laptop is only used to show the diagnostic messages. It’s not needed for normal operation. Electrically this setup is exactly the same as all the other CF-II/CF-III systems in droids today. I’ve only added my custom code to add the extra functionality.

I’d ordered a bunch of super strong ‘earth’ magnets last week and they arrived today. I’m hoping to use them in quite a few spots, hence the tall stacks.

The larger 3/4″ discs will be used to secure the battery boxes to the feet, the rods will be used on the removable back door, and the small 3/8″ discs in various spots, like securing the shoulder hubs to the legs for easy removal, and holding the front blue panel around the vents. I’m also going to experiment with using them to hold panels and doors closed, but they maybe too strong.

I’m really excited to share some programming work I’ve been doing on my sound system the last few days. I don’t think anyone has done this before with the CF-III within the group.

Some background, I was a little disappointed that the CF-III was only able to trigger one set of random or sequenced sounds, plus one sound per remaining switch/contact. And like a lot of people I was frustrated with having to name all the files 0AC.WAV, 1FC.WAV etc. etc. Talk about getting confused.

What I really wanted was to have multiple banks of sounds, both for generic sounds, chatting/chirps sounds, and multiple banks of music. Try as I might with all the HEX file naming I couldn’t get it to work – and emails to ACS confirmed that I was asking too much of the CFSOUND.INI file.

So I decided to throw the CFSOUND.INI away and try writing my own program in ACS BASIC that would provide at least the same functionality that most people setup today, plus a lot more.

If you saw my post from a few days ago, you’ll know that I have two RF Remotes hooked into my CF-III, a 4 channel relay which handles volume and a 12 channel relay for triggering sounds.

By moving to hand written code in the CFSOUND.BAS file I was able to do everything I wanted plus more. Here’s a round down.

New Functionality – All Uniquely Addressable

• Remote Volume Control
• Two banks of music, with easy toggle select. 12 sounds total, all uniquely addressable
• Generic Sound bank (20 wav files)
• Chirpy/Chatting Sound bank (15 wav files)
• Multiple Whistle Sounds on one key
• Multiple Sad Sounds on one key
• Long and Short version of the Leia message
• Scream
• Short Circuit
• Random Sound Mode – Toggle on/off random sound playing – just press a button an leave R2 talk to himself at random intervals.
• Easy to add more sounds to each bank
• Quick boot time. CF-III is ready in seconds instead of the normal boot time measured in minutes when you have lots of files.

And to top it off I can call my sound files meaningful names for easy changes in the future. No more HEX coded files. e.g. You can now have files called “chirp.wav”, “scream.wav” and “vader.wav”.

This is all via a standard CF-III and your basic RF Remote/Receiver. Nothing extra is needed.

The last couple of nights have been very entertaining and a little painful trying to work around the limits of the BASIC programming language when I’m used to programming in C or PHP. I know I’ve learned or re-learned a lot since I last time wrote a BASIC program 25 years ago.

I think my favorite addition is the random sound mode. So I can leave R2 chatting away while I concentrate on driving 🙂

I’m really excited that I was able to get all this done, and I will hopefully be posting the CFSOUND.BAS program file once I’ve done some more testing.

Watch this space for a demo video soon.

Here’s a short video giving an overview of the newly reconfigured sound system.

Then new dome motor (a surplus Pittman GM9236) arrived today and I thought I’d share a short video to compare it to the original underpowered GM9413 motor I had been using.

It’s still runs at 12V, so no need to upgrade my electrical system to 24V. It spins a lot faster and definitely has a lot more torque.

Here’s the original GM9413 for comparison.

And finally, here’s a quick side by side shot of the two motors, the GM9236 is on the left. It’s a little bit longer and has a small shaft at the bottom which I think is to connect an encoding wheel to.