Pertinax

[JakeSoft]

Very Cool! I was thinking of doing an Arduino based board myself, so was excited to find this thread. I just put a PC-Prizm into my wife's saber (and then managed to fry it by putting the battery in backwards), but don't have the $ right now to put a good sound card into mine, so I was thinking of slowly tinkering with an Arduino. This is partly just because I think I would enjoy doing it, and partly so it could be fully customizable, upgradeable, etc. For now I just modified a cheap hasbro board. For the main board, why did you go with a pro mini rather than a nano? For the sound module (WT588d), that doesn't have an SD card, right? So just the onboard memory of the card? How much sound can you store on it? Or are you also using memory on the Arduino? Also how many bits for the sound, and sample rate?

So glad you like it! Sorry to hear about the demise of your sound board. I'll do my best to answer your questions.

Regarding the Arduino:
This is actually my second go at building an Arduino-based lightsaber. (This was the first: http://forums.thecustomsabershop.com...6-Novus-Animus) For that first board, I did use a Nano so you could definitely do that if you are more comfortable with it. However, be aware of the power requirements. The Nano operates at 5 volts and needs about 5.5 volts to run properly. The Pro-mini I selected for Pertinax operates at 3.3V and only needs about 3.5 volts to operate. This opens the door to more battery options and makes the board more flexible. It's also more power efficient. I tried running the Nano-based board on 4 AAA alkaline batteries and the runtime was terrible; the board would keep rebooting when the power dropped below ~5.4 volts and that didn't take very long running 3 high-powered LEDs! The only way I was able to make it serviceable with AAA cells was to use expensive lithium batteries. If you use a Nano, do yourself a favor and plan to use a 7.4 rechargeable battery.

Also, the pro-mini is cheaper and smaller than the Nano, so that factored in as well.

Regarding the WT588D:
The flash memory to store the sounds is built right into the module by the manufacturer. I liked this idea because I didn't have to worry about SD card compatibility woes that plague so many other components of this type. The modules come with various flash sizes. The most common seems to be 8 megabytes and 16 megabytes, but 32M exist (although they are somewhat difficult to find). That may not sound like much, but that's plenty when you consider that many of the sounds are one second or less in duration. (The 1GB+ mini-SD cards that Plector and NEC boards support are really massive overkill for a single or even 2 lightsaber sound fonts, but you can't find SD cards smaller than that.)

The WT588D supports 12-bit audio processing. I re-sampled all of my sounds at 22KHz, at either 8-bits or 16-bits per sample. They work flawlessly if you stick to that. Other sample rates are supported, but that is what I know works for sure. Note that this is NOT the same sample rate that the Plector and NEC boards use, so if you are recycling sound font files from your fried Prizm, you'll need to convert them or come up with your own sound files from elsewhere. Check out my YouTube channel for more instructional videos on working with these modules. https://www.youtube.com/playlist?lis...9fOzKV0_ride3p

I hope this helps. Best of luck to you and happy holidays.

[forsytjr]

Thanks for the response, very helpful. Someone from the forums does sound board repairs, so hopefully the prizm will be back in action. I had seen a post on the Arduino forums saying the nano could handle low voltage ok, so good to know that hasn't been your experience. I did want to power it from a single 18650 battery, like the prizm, so I'll stick with the 3.3v mini if I do this.

So glad you like it! Sorry to hear about the demise of your sound board. I'll do my best to answer your questions.

Regarding the Arduino:
This is actually my second go at building an Arduino-based lightsaber. (This was the first: http://forums.thecustomsabershop.com...6-Novus-Animus) For that first board, I did use a Nano so you could definitely do that if you are more comfortable with it. However, be aware of the power requirements. The Nano operates at 5 volts and needs about 5.5 volts to run properly. The Pro-mini I selected for Pertinax operates at 3.3V and only needs about 3.5 volts to operate. This opens the door to more battery options and makes the board more flexible. It's also more power efficient. I tried running the Nano-based board on 4 AAA alkaline batteries and the runtime was terrible; the board would keep rebooting when the power dropped below ~5.4 volts and that didn't take very long running 3 high-powered LEDs! The only way I was able to make it serviceable with AAA cells was to use expensive lithium batteries. If you use a Nano, do yourself a favor and plan to use a 7.4 rechargeable battery.

Also, the pro-mini is cheaper and smaller than the Nano, so that factored in as well.

Regarding the WT588D:
The flash memory to store the sounds is built right into the module by the manufacturer. I liked this idea because I didn't have to worry about SD card compatibility woes that plague so many other components of this type. The modules come with various flash sizes. The most common seems to be 8 megabytes and 16 megabytes, but 32M exist (although they are somewhat difficult to find). That may not sound like much, but that's plenty when you consider that many of the sounds are one second or less in duration. (The 1GB+ mini-SD cards that Plector and NEC boards support are really massive overkill for a single or even 2 lightsaber sound fonts, but you can't find SD cards smaller than that.)

The WT588D supports 12-bit audio processing. I re-sampled all of my sounds at 22KHz, at either 8-bits or 16-bits per sample. They work flawlessly if you stick to that. Other sample rates are supported, but that is what I know works for sure. Note that this is NOT the same sample rate that the Plector and NEC boards use, so if you are recycling sound font files from your fried Prizm, you'll need to convert them or come up with your own sound files from elsewhere. Check out my YouTube channel for more instructional videos on working with these modules. https://www.youtube.com/playlist?lis...9fOzKV0_ride3p

I hope this helps. Best of luck to you and happy holidays.

[Whi-ja]

What an elegant way to include so many fantastic features; congratulations! Well done, and a good use of your professional skills.

[forsytjr]

I used PNP power transistors to convert a cheap hasbro board to drive the LEDs. Is the advantage of a MOSFET that it can drive the LED without using a lot of current from the arduino? Or would PNP's work just as well? And how do you vary the LED intensity? Is it by varying the voltage going into the MOSFET, or is it by using full voltage, but then turning it off and on at high frequency to adjust the percentage of the time it is on? Are you using high power resistors to prevent burning out the LEDs, or do you just make sure to drive the LEDs at the correct voltage?

[JakeSoft]

I used PNP power transistors to convert a cheap hasbro board to drive the LEDs. Is the advantage of a MOSFET that it can drive the LED without using a lot of current from the arduino?

Yes. I like N-channel MOSFETs because they can handle huge current loads and require very little current to drive the gate pins. That makes them perfect for use with a small Arduino.

Or would PNP's work just as well?

I'm not sure. Maybe, but you'd have to refer to the spec sheet of whatever PNP you're using to ensure the Arduino can supply enough voltage and current to fully drive the transistor.

And how do you vary the LED intensity? Is it by varying the voltage going into the MOSFET, or is it by using full voltage, but then turning it off and on at high frequency to adjust the percentage of the time it is on?

I used pulse width modulation (PWM) for the fading effect. The capability is supplied by built-in Arduino functions. Check here for instructions on how to fade an LED. It's really pretty simple.

Are you using high power resistors to prevent burning out the LEDs, or do you just make sure to drive the LEDs at the correct voltage?

Each LED die has it's own 3W resistor to protect them from being over-driven. The resistors are calculated in the usual way using Ohm's law.

[forsytjr]

lation (PWM) for the fading effect. The capability is supplied by built-in Arduino functions.

Thanks! PWM was the word I was struggling to remember. My PNP's worked with 10-20ma (a 100 ohm resistor), but I might as well do a MOSFET. I guess if you are doing PWM at full voltage, keeping the high watt resistors would make sense to get the right voltage to the LEDs.

[forsytjr]

Just an update on my progress. I got a wtv020-sd-16p card working with an Arduino pro mini, but am disappointed. The playback is not gapless, and it needs an amp. So I ordered a wt588d. But I do have a three axis gyro/accelerometer working. It's based in the 6050 chip and has some really nice libraries to support it. I'm able to get raw linear acceleration data and rotation speeds. But it also has an internal processor that integrates to get position and orientation. I managed to run a demo code where on the pc you can see an image that is updated with the board orientation in real time. So it seems very promising to do some cool motion based effects.

[JakeSoft]

Just an update on my progress. I got a wtv020-sd-16p card working with an Arduino pro mini, but am disappointed. The playback is not gapless, and it needs an amp. So I ordered a wt588d.

Yeah, when I was doing research for my project I looked at the wtv20 too but disregarded it after reading about those issues as well as some others.

But I do have a three axis gyro/accelerometer working. It's based in the 6050 chip and has some really nice libraries to support it. I'm able to get raw linear acceleration data and rotation speeds. But it also has an internal processor that integrates to get position and orientation. I managed to run a demo code where on the pc you can see an image that is updated with the board orientation in real time. So it seems very promising to do some cool motion based effects.

Awesome! You'll be able to implement more sophisticated event sensing than my solution which used only swing and clash sensors. I look forward to seeing how your saber turns out. You should start a build log and put a link here.

[MrCafe]

Wow. That is love for the craft right there. Amazing work.

[forsytjr]

Jake, would be willing to share your code? My sound card should be coming in today. When you say create a build log do you mean just to create an ongoing thread? Or is there a more official way to do a build log?