Hi all

After what has been a very steep learning curve for me, I have designed a one sided custom PCB for a lightsaber fx system.

However, regardles of how proud of it I am, I wouldn't mind someone taking a proper look as I'd like to get some feedback (see attached PDF for high res image and BOM).



As can just about be seen in the pic above, the system is mostly module based appart from the integrated charging circuit as I wanted to streach my knowledge some and used it as a learning tool. Saying that, I did nearly have a critical brain meltdown working it all out.

I also made this wiring diagram of the control section. I never got round to drawing a schematic of it as I've not tried to do one so complex before, though I do want to tackle it at some point even if just for the principal and practice.


I now face the prospect of having to teach my dyslexic brain how to code, not something I'm looking forward to for many reasons but I'll give it my best shot regardless.

 

Hi.

Please describe what you want your circuit to do, including the modules.

 

Hello Canobi,

From the wire diagram, we can see oneboard is connected to 5V, the other is running on 3.3V. The serial lines are connect directly to each other without a level convertor. Did you check the data sheets if the boards support mixed 3.3V, 5V level inputs ?

 

Hi.

Please describe what you want your circuit to do, including the modules.

Wow, thanks for the assist

The idea behind the design is this.

STARTUP

When power button is pressed:

• the arduino switches on the 3v3 regulator tied to pin A1
• opens the mosfet gate tied to pin 2 for the LED
• first triggers a blade startup sample
• then playes a looped sample continously (seemless transition from one to the other if possible).

INTERACTION

When values from the accelerometer are generated:
• between the ranges of 2g and 4g, motion sounds are triggered
•when values exceed 4g, clash sounds are triggered.

POWER DOWN

When power button is pressed for two seconds:

• the arduino stops looping function
• triggers blade deactivation sound
• closes mosfet gate to LED
• pulls pin A1 low to deactivate regulator
• goes to sleep mode until butyon is pressed again..


WT588D setup:

I designed the PCB to use the DAC facility and have it talking to the arduino via three line coms. As it happens I found some code for three line and one line which the module uses to talk to MCUs so can post them up if it helps.

The other modules are to provide correct voltage or amplify and work independently so no code needed for those.

 

For starters:

Where does the 5v come from?
Where does the 3.3v come from?

• the arduino switches on the 3v3 regulator tied to pin A1

Where is the regulator?

• opens the mosfet gate tied to pin 2 for the LED

Where's the mosfet?

• triggers blade deactivation sound

Speaker or buzzer or...?

If you designed the PCB, then you have the schematic diagram. Please share.

 

Hello Canobi,

From the wire diagram, we can see oneboard is connected to 5V, the other is running on 3.3V. The serial lines are connect directly to each other without a level convertor. Did you check the data sheets if the boards support mixed 3.3V, 5V level inputs ?

There are two resistors onboard the accelerometer for level shifting though its hard to tell from the diagram.

The 3v rail to the WT588D is a little more confusing as there was no other info in the datasheet other than it's for powering external memory and the voltage required. It's confusing because it has onboard memory so not sure why it needs to be connected.

 

For starters:

Where does the 5v come from?
Where does the 3.3v come from?


Where is the regulator?

Where's the mosfet?

Speaker or buzzer or...?

If you designed the PCB, then you have the schematic diagram. Please share.

I'll answer your questions in order.

The 5v comes from a micro boost buck module situated between the battery and arduino and is outlined in the first pic/attached PDF and supplies the arduino and Vdd of the WT588D.

The 3v3 comes from an LP2992 regulator situated just past the FDTI pins under the arduino and is marked as REG2. This supplies the Vcc input to the WT588D and Vcc to the accelerometer.

The mosfet is situated under the arduino next to pins 2, 3 and 4 and is marked as TR1.

The WT588D supports both DAC and PWM but wanted to go for DAC to use external amplification as the PWM can only achieve .5w max.

Um, unfortunately I dont have a achematic as I mentioned at the end of my firts post.

I am completely self taught and have no formal education on the subject (though I did try when I was younger but was rejected due to the colourblind issue) and as such never learned how to draw schematics, though I am slowly getting better at reading them.

 

Took a couple days work it out, but here is the schematic for the control section.

Going to start work on the PSU schematic next.

 

Hello Canobi.

Great project. You put the file for this Board to download? Where?

I would like to have it to send make a plate for me, here in my country.

I appreciate your information.

Tnx

 

Hi vborgnet

Wow, I've not looked at that board in a long time, it's even a little embarrassing really, tried to cram in too much too early so much of it turned out not to work properly, or at all but I guess we all have to start somewhere right?



I may still not be a pro but I've come a long way since then and prop fx hardware has always been and continues to be my primary focus.

I also fabricate PCBs, so if you want a custom board for your saber designed and made to your specs, I can do that too

Here's a couple saber fx PCB variations I designed and fabricated for folks recently:







I've also been looking into making the saber system totally modular as a kind of "mix 'n' match" deal:





And this is what my system looks like now (board is 24.42mm x 50.05mm, all hand soldered components too):



The revision for the MkII has an inegrated ADXL335 accelerometer and a few other useful additions. It's also my first two sided PCB design: