How to?... Custom Circuit boards for props.

LimeyBuilds

Well-Known Member
I've been using Adafruit soundboards and Arduino Nanos for lighting and sound in props, however they are large circuit boards that often take up far too much space. I keep seeing other DIY prop builders using their own special boards that seem to combine all the functions of these 2 into a board smaller than either one of them. Boards with almost impossible to see chips and components that look manufactured bespoke. I tried google, but couldn't get much info on how this might be wholly achieved. Like how do they find tiny chips that do the above jobs, and get them made as circuits? Just throwing this out as Someone here might have experience with lighting/sound in props like this.
I'm a quick learner, even with stuff I know nothing about when I start. I learned to sew to make a uniform. I wanted to make a leather shoulder holster, so i learned leathercraft. Someone was kind enough to write my first nano sketch and since then I have been able to write all my own just from seeing that one, and i know nothing about programming. So I know I can learn this if i know where to find the knowledge!
1726878168045.png
 
I actually went the other direction. I used to design all my own electronics and have boards made. I still do in some instances, but most of the time now I pull an Arduino Nano out of a drawer and knock something out in a couple of hours.

One value of designing your own is the ability to streamline. If you only need for outputs for LEDs a Nano is overkill. You can do that with a 555 time and a 4017 decade counter. There are also processors with less and more outputs depending on your needs.

The Arduino has made microprocessor boards much more accessible. If you really want to design your own boards it's time consuming, expensive and sometime you make a mistake that means redesigning the board and ordering more.

If you want to go that route come up with a project and start googling circuits. For instance "four LED sequential circuit". You'll find tons of schematics to start from. The problem with the internet is that some of the examples are missing information or are just wrong.

There are a lot of free board layout software's available. ExpressPCB has a simple software that's free, but you have to order the PCBs (the board without the components) from them. They are one of the cheapest options but Arduino boards are so much cheaper.

I've been doing electronic design professionally for over 25 years. It's a lot of fun, but the learning curve is expensive. You might find some videos on YouTube about electronic design.
 
I actually went the other direction. I used to design all my own electronics and have boards made. I still do in some instances, but most of the time now I pull an Arduino Nano out of a drawer and knock something out in a couple of hours.

One value of designing your own is the ability to streamline. If you only need for outputs for LEDs a Nano is overkill. You can do that with a 555 time and a 4017 decade counter. There are also processors with less and more outputs depending on your needs.

The Arduino has made microprocessor boards much more accessible. If you really want to design your own boards it's time consuming, expensive and sometime you make a mistake that means redesigning the board and ordering more.

If you want to go that route come up with a project and start googling circuits. For instance "four LED sequential circuit". You'll find tons of schematics to start from. The problem with the internet is that some of the examples are missing information or are just wrong.

There are a lot of free board layout software's available. ExpressPCB has a simple software that's free, but you have to order the PCBs (the board without the components) from them. They are one of the cheapest options but Arduino boards are so much cheaper.

I've been doing electronic design professionally for over 25 years. It's a lot of fun, but the learning curve is expensive. You might find some videos on YouTube about electronic design.
I need to make things smaller by far than the ready-to-go boards. Just a matter of finding the components that can do t hat and how to set them up. I always make my circuits on a breadboard in advance.
 
There are really small microchip microprocessors. They have a lot of design help. Here's their site https://www.microchip.com/. One of the ways you can shrink the boards is to skip the microprocessor and go simpler. It limits the number of functions a board can do, but if all you need is some LEDs blinking a pattern that can really reduce the footprint of the boards. Old school clocks, decade counters, and shift registers is all they used in the 80's and 90's sci-fi.

If you have some details about what you're trying to do I can point you to the right resource.
 
There are really small microchip microprocessors. They have a lot of design help. Here's their site https://www.microchip.com/. One of the ways you can shrink the boards is to skip the microprocessor and go simpler. It limits the number of functions a board can do, but if all you need is some LEDs blinking a pattern that can really reduce the footprint of the boards. Old school clocks, decade counters, and shift registers is all they used in the 80's and 90's sci-fi.

If you have some details about what you're trying to do I can point you to the right resource.
Thank you! It was your initial Sketch, I believe, that allowed me to figure out how to make lighting code work for various projects.
Here is a perfect recent example of where one tiny circuit designed to fit would be ideal:
In the video, I have a Discovery Phaser. It has no sound as i could not fit a soundboard to make it go pew pew and pee-ew pee-ew when the trigger is hit in either stun or kill mode. Adafruit soundboards allow for 2 sounds in the two modes but are large and overkill for a phaser pew project.
In this phaser i was able to get the lighting to change from blue to red using a momentary switch with a DF Beetle i had around and playing with the code for it, but that was a tight fit.
Ideally it'd do everything in the video plus pew/pee-ew in blue/red. I would settle for a single pew sound if I had to. The sound cannot be a simple tone, but has to be the sound file taken from the show to match the TV effect.

EXAMPLE PHASER IN THIS VIDEO
 
What's your max board size for that project ? I did a lasertag version using one of the models on thingiverse I reworked and hollowed out. It uses my lasertag gun board which I have developed over multiple years for use in all my tag gun builds.

Like you I needed a smallish board to fit in many gun replicas so ended up developing my own using PIC chips as the basis. I then added on a wt588d sound board. I ended up with a board that has 4 switch inputs, has 4 outputs that can drive normal leds and also has 2 high power outputs using mosfets that I use to drive 1 or 2 IR leds and the muzzle flashes. All powered from a lithium cell (3.7-4.2v). I then customise the sounds and configuration to suit my various projects. Setting different ammo capacities etc as well as rates of fire.

For the disco phaser I used a commercial battery monitor board for the leds in the grip that you can activate to light up and show battery level remaining.

Unfortunately as I also had to include a lens assembly to focus the IR beam (it shoots our targets from over 100m away) to fit it in I had to make the P1 non removeable.

It can take years to develop something suitable, especially if you are learning from scratch. Like 13doctorwho I originally started with discrete chips to generate frequencies, count ammo etc. Repurposing sound boards out of toys for the sounds.
Then I discovered PIC micro's taught myself how to code them, built pcb's for them in the shed using acid etching with stuff from Maplins. Using microcontrollers makes things much easier and smaller. Eventually refining things over years. Now I get pcb's made in china but then assemble them myself and program them up.

I do still use Arduino Nano's for some props, like our medical healing devices for our games as there's more room in those but for most things I have to use custom built stuff due to size constraints.

I would disagree that skipping a microprocessor can result in a smaller board even for just blinking an led. Microchip do some tiny micros that don't even need a crystal and have a very small component count. a 6 or 8 pin soic with a smt capacitor running from its built in oscillator is hard to get smaller.
 
What's your max board size for that project ? I did a lasertag version using one of the models on thingiverse I reworked and hollowed out. It uses my lasertag gun board which I have developed over multiple years for use in all my tag gun builds.

Like you I needed a smallish board to fit in many gun replicas so ended up developing my own using PIC chips as the basis. I then added on a wt588d sound board. I ended up with a board that has 4 switch inputs, has 4 outputs that can drive normal leds and also has 2 high power outputs using mosfets that I use to drive 1 or 2 IR leds and the muzzle flashes. All powered from a lithium cell (3.7-4.2v). I then customise the sounds and configuration to suit my various projects. Setting different ammo capacities etc as well as rates of fire.

For the disco phaser I used a commercial battery monitor board for the leds in the grip that you can activate to light up and show battery level remaining.

Unfortunately as I also had to include a lens assembly to focus the IR beam (it shoots our targets from over 100m away) to fit it in I had to make the P1 non removeable.

It can take years to develop something suitable, especially if you are learning from scratch. Like 13doctorwho I originally started with discrete chips to generate frequencies, count ammo etc. Repurposing sound boards out of toys for the sounds.
Then I discovered PIC micro's taught myself how to code them, built pcb's for them in the shed using acid etching with stuff from Maplins. Using microcontrollers makes things much easier and smaller. Eventually refining things over years. Now I get pcb's made in china but then assemble them myself and program them up.

I do still use Arduino Nano's for some props, like our medical healing devices for our games as there's more room in those but for most things I have to use custom built stuff due to size constraints.

I would disagree that skipping a microprocessor can result in a smaller board even for just blinking an led. Microchip do some tiny micros that don't even need a crystal and have a very small component count. a 6 or 8 pin soic with a smt capacitor running from its built in oscillator is hard to get smaller.
At the moment a lot of this is foreign to me but the none-laser related stuff sounds like something i need to know more about and how to program/create these. I'll be looking up the wt588d.
I tried testing a DFPlayer mini, but i couldn't get output on the little 2w mini oval speakers. Can't find 3w at that small size anywhere.
 
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Yeah. 2W at 3 volts mean the current is 0.67 Amp. The really small sound ICs aren't going to drive that. You could use a MOSFET, but can your tiny battery source an that much current? Getting a loud sound from a small board and speaker is challenging. You need to decide how loud you want the sound and work back to a design. There may be some physical limitation on how loud a sound you can get in your form factor.

I've done a few sound circuits in small props (like a sonic screwdriver), but nothing loud enough for a phaser.
 
The smallest speaker that I would say generates a good amount of volume wont fit in a phaser. I'm partial to K50 speakers from Visatron for larger stuff like rifles. They are 50mm in diameter though. When coupled with a OEP3W or similar 5v amplifier modules you can get some pretty decent volume, enough to be heard even outdoors at 'combat ranges'. Although the bigger the speaker the better in general.

For my phaser I used a 20x40 speaker R-TECH 350207 Miniature Loudspeaker Rectangular 40 x 20mm 8 Ohm located behind the rear gold fins (with some vents) again coupled with a small 5v amp module. One thing often overlooked with small builds is that the shape of the speaker enclosure/cutout/void can make a large difference to apparent volume.

Using a lithium 1S setup for power has several advantages. One you can remove all voltage regulators from your circuitry. Pic chips and other common micros will quite happily run from 3-5v. Same with common amplifier modules. The sound modules are also in that voltage range. That makes your boards smaller and more efficient. A decent li-po or Li-Fe (14500, 18650 etc) cell can easily supply several amps current. With some capacitors to smooth out larger draw periods it can work very well.

Btw one of the reasons I went with the wt588d instead of something like the Dy-sv17 or DF player is it can be controlled in 1 wire mode. A significant advantage when using a 8 pin chip that only has 5-6 usable output pins.

The only difference between a prop gun and a lasertag gun is fitting an IR led and lens assembly to transmit coded IR. Functionally even my props still simulate whatever it is where possible, so triggers, reload, fire modes etc. Even when not fitting a lens you still want to pulse drive a visible muzzle flash led. That way you can get it very bright. With different add on modules I've used the same basic board design in everything from a glock, to a pulse rifle. About the smallest I've been able to go without going to surface mount components is a 'working' PPG. My eyesight's getting a bit bad for working with smt nowadays lol.

PPG.jpg
 
Yeah. 2W at 3 volts mean the current is 0.67 Amp. The really small sound ICs aren't going to drive that. You could use a MOSFET, but can your tiny battery source an that much current? Getting a loud sound from a small board and speaker is challenging. You need to decide how loud you want the sound and work back to a design. There may be some physical limitation on how loud a sound you can get in your form factor.

I've done a few sound circuits in small props (like a sonic screwdriver), but nothing loud enough for a phaser.
It's probably about the same volume. Here is how it sounds with the Adafruit soundboard, mono amp, and 2W 8ohm mini oval speaker on my standard 3.7 LiPo:
Frankenphaser VID
Even in this the sound quality is so-so.
 
That's actually louder than I expected. Most of these playback modules, or ICs, don't have the greatest sound quality. It usual a combination of using a sound clip with so-so quality into so-so quality cable into a module that is usually so-so quality... not to mention the output chain.

Is the discovery phaser that much smaller than the "Frankenphaser" that the same electronics won't fit? I don't watch modern trek, so I don't know how they compare in size.
 
It's probably about the same volume. Here is how it sounds with the Adafruit soundboard, mono amp, and 2W 8ohm mini oval speaker on my standard 3.7 LiPo:
Frankenphaser VID

That's actually louder than I expected. Most of these playback modules, or ICs, don't have the greatest sound quality. It usual a combination of using a sound clip with so-so quality into so-so quality cable into a module that is usually so-so quality... not to mention the output chain.

Is the discovery phaser that much smaller than the "Frankenphaser" that the same electronics won't fit? I don't watch modern trek, so I don't know how they compare in size.
The Disco Phaser has a functioning removable P1, and once removed the interior of the P2 is hidden, whereas it's all open in the Frankenphaser and the 'hood' covers all the sin.
 
Not 100% sure if these links will work as its the first time uploading to youtube but...

- ppg sound volume from a wt588d module in pwm mode with no amplifier into a 40x20 speaker linked previously

- disco phaser with the sound from a wt588d module in amplifier mode and piped into a OEP3W amplifier module.

Not too much difference until you start putting a larger speaker on. At that point the amplifier makes a lot more volume.
 
Not 100% sure if these links will work as its the first time uploading to youtube but...

- ppg sound volume from a wt588d module in pwm mode with no amplifier into a 40x20 speaker linked previously

- disco phaser with the sound from a wt588d module in amplifier mode and piped into a OEP3W amplifier module.

Not too much difference until you start putting a larger speaker on. At that point the amplifier makes a lot more volume.
Yes! I need to learn how to make the disco phaser work using those components (I'm assuming it's much smaller than using a beetle for lighting and an Adafruit for sound) How did you control lights in this one, may I ask?
So firstly I need a wt588d and a OEP3W with an R-Tech 350207 speaker.
{Doesn't look like I can get a 3W one anywhere now.}
 
Everything is controlled by a PIC micro. But almost any microcontroller will work as long as it has enough input/output pins to handle whatever you need to do. I designed 2 boards I commonly use. One uses an 8 pin pic chip (5 I/O). That use 2 pins for inputs, 2 for outputs (leds etc) and 1 for controlling the wt588 module in single wire mode. That's for really space constrained builds.

The other board I use an 18 pin PIC which has minimum of 13 I/O. For that one I have 4 inputs, 4 outputs (leds etc), 1 for the sfx control, and then a couple for and I2C or spi like interfaces. There are 4 digit digital displays that are driven by 2 lines which are handy for things like pulse rifles :) Even that board fits in the grip of the PPG though so its not huge.

One of my outputs is always connected to a logic level mosfet. Which is capable of driving several amps. So with the right resistors and using a short pulse you can actually drive 1 or more leds at a current that would normally destroy them if you just turned them on. But because its on for a very brief period it doesnt burn up and you get a very bright flash. The same mosfet can also be used to drive a motor if needed or any other moderately high current device.

Code was all done the hard way, no libraries like you get on an arduino, but that's cause I have my own. Also with my stuff having to transmit very precisely timed IR pulses the arduino timers aren't precise enough to work reliably so I just rolled my own. You are probably better off using a micro that does support the arduino libraries as that's not going to be a factor for you. Will make coding much simpler.

The thing about most microcontroller families is that nowadays they are all pretty similar, they come is all sorts of packages and the requirements to run them are all very similar. So you just pick one that has the the peripherals you need (if any) and that you can get the programming setup for.

Your biggest problem from what I can tell is that you will have to learn to read and interpret electronics data sheets (which are not designed to be straightforward), then work out a schematic with all the 101 electronics design rules and gothchas for the myriad of components available, translate that schematic into a board layout using some pcb design software (such as KiCad) and then get them made and hope you didn't miss anything. Then you have to program up the boards using a suitable programmer as you cant just plug in a USB cable. It is a VERY steep learning curve.
Its not impossible, just difficult. And possibly expensive.

Its why most people use a ready made board and environment like the arduino's where you can just plug and play and get right to the coding stage.

As for the OEP3W, well I have about 9-10 left but I also use the XPT8871. Its a bit louder than the OEP3W and uses a bit more current as well as being a bit bigger physically.
Modules from the chinese sites come and go for availability which is where knowing how to test and figure out any interfacing components required is handy. With them being cheap I generally buy samples of anything that looks interesting. I've just got in 2 more types of amps that I need to have a play around with and see if they are any use. At least one of them should be a good replacement for the OEP3W.

Feel free to drop me a PM and I'll shoot you my contact details if you want to discuss anything in detail. I think you are in the UK too aren't you ?
 
Everything is controlled by a PIC micro. But almost any microcontroller will work as long as it has enough input/output pins to handle whatever you need to do. I designed 2 boards I commonly use. One uses an 8 pin pic chip (5 I/O). That use 2 pins for inputs, 2 for outputs (leds etc) and 1 for controlling the wt588 module in single wire mode. That's for really space constrained builds.

The other board I use an 18 pin PIC which has minimum of 13 I/O. For that one I have 4 inputs, 4 outputs (leds etc), 1 for the sfx control, and then a couple for and I2C or spi like interfaces. There are 4 digit digital displays that are driven by 2 lines which are handy for things like pulse rifles :) Even that board fits in the grip of the PPG though so its not huge.

One of my outputs is always connected to a logic level mosfet. Which is capable of driving several amps. So with the right resistors and using a short pulse you can actually drive 1 or more leds at a current that would normally destroy them if you just turned them on. But because its on for a very brief period it doesnt burn up and you get a very bright flash. The same mosfet can also be used to drive a motor if needed or any other moderately high current device.

Code was all done the hard way, no libraries like you get on an arduino, but that's cause I have my own. Also with my stuff having to transmit very precisely timed IR pulses the arduino timers aren't precise enough to work reliably so I just rolled my own. You are probably better off using a micro that does support the arduino libraries as that's not going to be a factor for you. Will make coding much simpler.

The thing about most microcontroller families is that nowadays they are all pretty similar, they come is all sorts of packages and the requirements to run them are all very similar. So you just pick one that has the the peripherals you need (if any) and that you can get the programming setup for.

Your biggest problem from what I can tell is that you will have to learn to read and interpret electronics data sheets (which are not designed to be straightforward), then work out a schematic with all the 101 electronics design rules and gothchas for the myriad of components available, translate that schematic into a board layout using some pcb design software (such as KiCad) and then get them made and hope you didn't miss anything. Then you have to program up the boards using a suitable programmer as you cant just plug in a USB cable. It is a VERY steep learning curve.
Its not impossible, just difficult. And possibly expensive.

Its why most people use a ready made board and environment like the arduino's where you can just plug and play and get right to the coding stage.

As for the OEP3W, well I have about 9-10 left but I also use the XPT8871. Its a bit louder than the OEP3W and uses a bit more current as well as being a bit bigger physically.
Modules from the chinese sites come and go for availability which is where knowing how to test and figure out any interfacing components required is handy. With them being cheap I generally buy samples of anything that looks interesting. I've just got in 2 more types of amps that I need to have a play around with and see if they are any use. At least one of them should be a good replacement for the OEP3W.

Feel free to drop me a PM and I'll shoot you my contact details if you want to discuss anything in detail. I think you are in the UK too aren't you ?
I am, thank you. I've a lot to look into there!
 
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