Building An Alternative to Blastercore: E-11 Sound/LED Board

[swmand4]

I ran into a bit of a snag... turns out I used the inner diameter of a real Sterling L2A3 as my basis for how much room I have to work with. As a result, the board is too big (1.3") to fit inside PVC pipe builds with a 1.25" ID. I'll have to go back and modify a lot of things to shrink the board down to ~1.2". It's doable, but frustrating nonetheless.

[Locitus[Admin]]

That's unfortunate!

Hang in there!

[TK bondservnt[501st]]

In some situations it might be better to put the board in 3 parts.  power and sd card for one board, led and propagation on one board, sound amplifier and speaker connections on another board.

 

I suggest considering placing the electronics in the front of the blaster, instead of the back.

batteries can also fit inside the front, or even in the handle of the blaster itself.

 

you could also consider making 2 areas for batteries.  I'd also like to see a charging system for batteries.

[swmand4]

In some situations it might be better to put the board in 3 parts.  power and sd card for one board, led and propagation on one board, sound amplifier and speaker connections on another board.

 

That would provide maximum flexibility, but would also increase cost and physical space. I'm using an MP3 decoder chip that directly drives speakers, so there's no need for a sound amplifier section. Though I don't know how loud it can go so this may change in the future. There will be three boards - one for main electronics, one for the counter box, and one for the barrel LEDs. I may eliminate the barrel LED board to save cost. I may also create my own 3W RGB high intensity LED board.

 

I suggest considering placing the electronics in the front of the blaster, instead of the back.

batteries can also fit inside the front, or even in the handle of the blaster itself.

 

My personal plan is have an inner barrel visible that contains the LEDs for the propagation effect. The inner barrel will be frosted acrylic tubing with an OD of 5/8". The frosted finish should diffuse the LED light to even it out and help make it look like the bolt is traveling through the inner barrel. This also emits light from the entire barrel, not just a single line of vent holes. You should be able to see some color around the t-track. I'm also placing a vibration motor in the main barrel for force feedback.

 

So my main barrel stuffing plan goes in this order, from back to front: electronics, speaker, vibration motor, inner barrel with LEDs, super-bright RGB LEDs. I'll post a diagram as I make more progress. The batteries will be mounted in the clip and mag well.

 

Is there really enough space in the handle for more batteries?

 

This is just the way I've decided to do it; the board has enough flexibility to allow the electronics to be in the front and to use discrete LEDs in the vent holes if you so choose.

 

you could also consider making 2 areas for batteries.  I'd also like to see a charging system for batteries.

 

The board has a barrel power connector and 8.4V Li-Ion charge controller for external charging at 12VDC. I'm not happy at the moment that you have to open the end cap to charge the battery, but I don't think there's any way to incorporate a power plug on the outside of the blaster. This also means a very particular kind of battery must be used with the system (7.2V Li-Ion battery). I'm planning on using a 7.2V 650mAHr battery that fits in the magazine, but that is again flexible. It could be a physically larger 7.2V 2500mAHr battery placed in the barrel.

 

Thanks for the comments and suggestions! Keep 'em coming

[TK bondservnt[501st]]

I personally would not use the clear inner front barell.  interesting but not my lil cup o tea!

[Locitus[Admin]]

Is there really enough space in the handle for more batteries?

 

Yes, I would say you could fit 2 AA's in there. But considering most handles are cast solid it would require drilling out a lot of resin. 2 AA's side by side would be a squeeze but easily stacked vertically. 2 AAA's however would easily fit side by side.

[TK bondservnt[501st]]

I plan to offer kits where the trigger has a switch, and batteries are cast inside the handle.

will be made in 2 halves, with all parts installed.

Edited May 26, 2013 by TK Bondservnt 2392

[swmand4]

I personally would not use the clear inner front barell.  interesting but not my lil cup o tea!

 

That's why I'm going for a flexible design. Don't like the inner barrel idea? Mount your own LEDs and plug them into the provided terminals. Also, it's a frosted opaque tube (not clear).

 

Although, I did have to shift a bunch of stuff for the counter box out to the box itself. Keeps the FFC connector down to a reasonable size, but basically limits compatible electronics to only mine. Oh well.

Edited May 27, 2013 by swmand4

[swmand4]

How useful would it be to have a green barrel propagation effect? The high intensity LED at the front of the barrel can produce green light and the barrel can, at the moment, only do blue and red. Before I go too much further, I can revise and elongate the design to add green barrel LEDs. My thinking here is that the electronics can be used for Star Wars weapons other than an E-11...

 

Are there even Star Wars weapons that fire green lasers?

[seantrooper[TK]]

maybe a wookiee bowcaster?

 

If you can make this at an affordable price, I'd definitely be keen for one! This is looking AWESOME

Edited May 28, 2013 by seantrooper

[swmand4]

Prepare For Photogeddon

 

I've made major progress in the last week or so. The hardware is almost finished and initial part selection has been completed. Good news is the price is coming in at moderately reasonable at quantities of 25. Bad news is there are a lot of wires I'd have to crimp myself, if I choose to go that route. I could always provide the material unfinished (wires cut to length and stripped) and say, "you go crimp 85 wires for your board." I would have used flat flex cables everywhere as they're easier to use and take less time to install, but I want the board to be flexible. FFC's would prevent someone from installing through-hole barrel LEDs in the vent holes.

 

The only thing I'm still undecided about is the power switch. I've seen it as a slide switch on the board and a toggle switch in lieu of a charging handle. I thought maybe I could use the screw cover (?) next to the selector switch on the handle as a placement for a plunger switch. I'll order a few possible parts and see if anything fits. As the connector is a plug on the board, there are a lot of options.

 

I managed to jam another LED driver on the board without increasing the size of the overall board. Now the barrel propagation effect supports full RGB color! The drivers I use are designed for common anode use, so if you choose to use discrete LEDs in the barrel vent holes they will need to have the positive sides connected together. I had to move the trigger connector to route some traces, but I like where it is better since it's away from fast switching traces. Less noise in the ADC line that way.

 

 

The inner barrel board uses 9 RGB LEDs. I wanted through-hole LEDs and cutouts to better diffuse light in the tube, but this should work just as well. I'm currently planning on using an 8" long 5/8" OD acrylic tube with windows frost for the inner barrel. I roughly measured the spacing of the vent holes and guesstimated the distance from the front of the PCB. It doesn't really matter with a diffuser, but I will almost certainly adjust the placement of the RGB LED modules before calling it done.

 

 

I couldn't find a reliable supplier of the RGB modules for the end of the barrel, so I created my own. It's costs about twice as much ($6.50), but it uses less power, has brighter LEDs, and should fit snuggly in the barrel. I designed it so wires could be attached in two places. If the inner barrel diffuser and PCB is used, the wires can be contained inside there and kept out of view. If the inner barrel and PCB is not used, the wires can be plugged into the provided sockets. You could also use the inner barrel diffuser and keep the wires on the outside - might look more futuristic to have wires visible in the barrel...

 

 

The counter box hasn't changed very much since I first posted it, but I'll add it again to make a post that has everything in one place Even though the schematics have changed a bit since they were initially posted, that would be another 9 giant images so I'll hold off for now. I'm also leaving out the inner planes.

 

 

Comments and suggestions are welcome. I'm still trying to find a name better than "The Pew-Pew Maker."

[Locitus[Admin]]

Fantastic stuff! It would be so cool to see this come back out of an assembly plant all done.

[swmand4]

I'm at a bit of a stand-still until I figure out what I'm doing battery-wise. I'm talking with a battery manufacturer to see if they can come up with a cost-effective pack that will fit inside the magazine. If they can, it will be a 3.6V Li-Ion battery pack with ~2000mAhr capacity. Or so I'm told - I'll know more in the next few days. Using this voltage battery would require a boost regulator to power the super-bright LED. Not impossible to add to the design, but the board isn't currently set up for it and would require some redesign.

 

In the mean time, I did some test fits.

 

 

Sorry for the last blurry picture.

 

Getting close now! Once the final battery is selected, I'll be ready to order parts and test part fit. Then it's on to ordering the PCB and assembling the first prototype!

[Bernarr]

What are the dimensions for the space you're looking to fit the battery into?

[swmand4]

What are the dimensions for the space you're looking to fit the battery into?

 

30mm width X 18mm height. Possibly two 14500 Li-Ion cells in parallel could fit. If the pack the company comes up with costs too much, I'll end up going with this off the shelf one.

 

And thanks, Chris, for the link to the Arduino SD card library. There's some good stuff there that should help me figure it out.

[Bernarr]

No problem! I've found it pretty useful myself    If you can squeeze a few more mm out of that space, this may work for you-

http://www.all-battery.com/li-ion1865074v2600mahbatterypcbmodulewith22awgbareleads.aspx

 

You'd need another 1mm thickness and 7mm width, but it's a 7.4v pack with 2600mAh of juice

 

Or maybe this one-

http://www.all-battery.com/7.4v1150mAhLi-PolyLipoBatteryPackwithPCBandBareLeads-31165.aspx

 

Also 7.4v, but with a lower 1,150 mAh of juice, but it's a bit smaller, 34mm wide and 10mm thick

Edited June 10, 2013 by Bernarr

[swmand4]

No problem! I've found it pretty useful myself    If you can squeeze a few more mm out of that space, this may work for you-

http://www.all-battery.com/li-ion1865074v2600mahbatterypcbmodulewith22awgbareleads.aspx

 

You'd need another 1mm thickness and 7mm width, but it's a 7.4v pack with 2600mAh of juice

 

Or maybe this one-

http://www.all-battery.com/7.4v1150mAhLi-PolyLipoBatteryPackwithPCBandBareLeads-31165.aspx

 

Also 7.4v, but with a lower 1,150 mAh of juice, but it's a bit smaller, 34mm wide and 10mm thick

 

I appreciate the assistance in the search, Chris. I don't think I can go any larger than 30mm, but any rechargeable 7.2V Li-Ion/Li-Polymer battery should work fine with this setup. So if someone else were to put my electronics in their blaster, they could use one of the packs you linked to and place it somewhere other than the magazine.

 

I wonder if the added weight out the side of the blaster will affect how it feels when held?

 

I also just heard back from a battery manufacturer regarding a custom sized pack. They can do it, but it would cost more than the electronics themselves to produce and test. Not surprising. Guess I'm sticking with the original 7.2V 14500 or 14430 cell pack. Saves me some redesign time I'm also concerned about shipping regulations regarding Li-Ion batteries; if I made a kit of these electronics, I don't know that I could ship it via air freight. Something to look in to.

 

What this effectively means is that I'm ready to order parts for PCB pad and size testing

Edited June 12, 2013 by swmand4

[Bernarr]

Yep, definitely not surprised about the battery guys. Everything costs more in small batches! Inside the US you'd be fine, you'd just have issues shipping them internationally if you use the USPS.

Batteries don't weigh that much, I don't think it would make too much of a difference hanging off the side of the barrel.

[swmand4]

I started writing some of the MCU code, just basic initialization stuff and getting the RTOS working. It tends to help iron out any bugs in the hardware when you have to verify a certain pin can actually do the thing you want it to.

 

I've decided to add a 20MHz external crystal oscillator to the ATMega328P. This way it will run faster and I can actually use USART to debug. The POS internal oscillator has a +/- 10% tolerance, which simply will not work for USART. SPI and I2C would work even on the internal RC oscillator, but this solution works better. It also has the added benefit of tighter control over the PWM signals for the motor and super bright LEDs. To accommodate the oscillator, I had to move some functionality around to free up the required XTAL pins. Now the drivers for the LED counter bars and the green barrel propagation LEDs are daisy chained. Data flows into the LED Bars driver, out of the LED bars driver, and into the green barrel LEDs driver. Still allows me to leave off the green driver if I want to.

 

Received my DVH E-11 kit as well. Once I figure out how to drill my barrel, I'll be starting that as well. Have to have something to put these electronics in. Oh, and the barrel is clear acrylic tubing, so you can see the electronics and how it all fits together inside. At least before I paint it.

 

This thing is starting to come together nicely.

[Bulldog44[TK]]

Post some pics when you get a chance! Sounds like a great set up and very interested to see how it fits in the DVH kit. I am putting my kit assembly on hold until I see how you assemble yours with the electronics. Your last post post with all the electronics lingo went right over my head but it sounds good! Looking forward to hearing more of your progress. Best of luck!

[swmand4]

After days of poring over my design and trying to find some alternatives to the connectors I chose (and failed), I decided to order parts to start building this thing. Then I discovered two things:

 

One, my Lithium Ion charge controller is no longer in stock anywhere and will not be replenished until September 25th.

 

Two, I forgot how expensive R&D costs are.

 

Thus, this project will have to wait a little until I redesign the charge controller and have some more money to spend on hobbies. Hopefully it won't be more than a few weeks. Don't worry, I'll finish this thing eventually.

[Locitus[Admin]]

If you need some cash, I'll be happy do donate to the cause.

[swmand4]

Thanks Mathias, I appreciate that. I think I can handle the R&D costs - I just need to convince myself to spend the money

[swmand4]

After a long hiatus, I'm starting to look back into this project. Turns out working 8 hours a day and coming home and working another 6-8 hours on the same type of project drains a lot out of you.

 

I went to purchase all of the parts needed and learned that the VLSI audio chip I want to use is not carried by Digikey or Mouser. This is a problem as purchasing directly from the company in Finland is expensive. They only offer courier delivery to the USA and it costs a grand total of $72 for a single chip. I've contacted a possible 3rd party distributor in the states that has them in stock to see what they want for a couple of them.

 

Other than that, I'm thinking of eliminating the Li-Ion charge controller from the board and using an external pre-assembled off the shelf one. That should alleviate my concerns with improper battery charging. Instead of deleting the charge control circuit from the board, I'm going to add an optional bypass around it. The down side is the external charger is more expensive.

 

Will update more once I hear back from the distributor.

Edited January 26, 2014 by swmand4

[TK bondservnt[501st]]

an external charger only makes sense!  I have been looking closely at this project!