engine sound generator for electric models [Archive]

KSU Flyer

Jun 28, 2005, 07:00 PM

Guys,

I don't know if this is way out there or not, it may have already been dicussed here too. I'm posting this based on some conversation that got going over in the parkflyer forum, and has me a bit interested.

Anyway, one of the things I miss most about my slimer days is the sound of a nice 4 stroke engine on my plane. I just liked the realism it added to my models. So, as the title suggests...How could this be done electronically.

My preference as well as others would be to have a way to have different sounding engine tones, emulating the sounds of the different full scale engines. Especially and old radial style engine. What would also be very neat is to have the sound change with throttle stick position.

One obvious restriction would be how loud could make the sound. All this would be for not if we couldn't hear it while the plane was flying around. However, most of the outrunner style motors are next to completely quiet, so you wouldn't be fighting that. My other thought is that some of these darn cell phones have such loud ringers/speaker which play sound etc., so the miniature speaker shouldn't be a limitation. For instance take a look at this link.

http://www.regalusa.com/high_power_miniature_speakers.html

Ok, thats probably the simple part. We need a way to recreate the audio signal, and drive the speaker. So, I found this.

http://www.vlsi.fi/vs1011/vs1011.shtml

This link provides take you to a "Very Low power MP3 Audio Decoder IC". This would allow someone to record an engine sound of your choice, upload it to the IC's RAM, then play it. However, that may or may not work for varying throttle positions. It may work out however that as you monitor the PWM signal from the throttle stick that you could play different MP3 tracks. That is if 7.5 Kb is enough space to store much of a looping MP3.

I dunno, maybe thats out there a bit...somebody bring me back to earth.

-Mike

KSU Flyer

Jun 28, 2005, 07:04 PM

Just found this, so maybe there is already an off the shelf solution?

http://www.phoenixsound.com/index.html

markmi

Jun 29, 2005, 03:12 AM

Hi Guys

Possibly the easiest solution is to use a CMOS circuit similar to this one. Change the cap between 220pf to 1µf to operate at a lower frequency and use the voltage from the motor to drive this circuit as it is voltage sensitive, low voltage = low beeps, higher voltage = high beeps. Use a Piezo sounder for the sound output.

Mark

markmi

Jun 29, 2005, 03:19 AM

Opps

navkan

Jul 05, 2005, 09:53 PM

or, you could attach asmall piece of cardboard to the nose where the prop will flip it, just like I used to do with a baseball card in my bike's spokes back in the days that a bike was a new invention :D

Ekim

Aug 11, 2005, 10:41 AM

well........ as for the space issue..... if you use an ATMEL microcontroller as I am for my combat system, you buy extra flash chips whic can be read by the main controller

Red 61

Aug 11, 2005, 11:30 AM

This is the combination I've been working on:

http://store.qkits.com/moreinfo.cfm/FK928
$20 plus shipping.

http://www.regalusa.com/high_power_miniature_speakers.html
Minimum order of 500 at $3.49 each. I currently have two free samples.

I've got a .wav file of some pretty darned good gunfire. I tried uploading it several times, but it's too big (even when I zip it). I'm more interested in gunfire than engine noise... ;)

EDIT --> According Qkits, the FK928 outputs just less than 400 milliwatts. Checking the spec sheet for the RH-16-E speaker (this is what I have two of), .3 watts (nominal) will give me 73 decibels of sound. A vacuum cleaner makes a sound of 70 decibels, so it should be pretty loud! :)

The real question is, will you be able to hear it at a distance, over the sound of the motor and prop? :confused:

Acetronics

Aug 12, 2005, 05:41 AM

Hi, Guys

Do you have a little idea of the amplifier power and speaker weigh you need to make something "ear-able" :confused:

Seems the answer is NO ...

Alain

lazy-b

Aug 12, 2005, 07:49 AM

I guess, its easier just to install a real Glow Engine, I love to hear the sound of Four Stroke engine.

How about a small noise maker (Thin Sheet Plastic, that make noise when propeller hit it) and install a small buffle to make sound like a four-stroke engine......I use to have a small toy gun that use this principle.

Ellion

Acetronics

Aug 12, 2005, 09:25 AM

I think a model of the little gadget mounted aboard the JU 87 ( Diving bomber ) could be the most realistic sound available ... ( siren activated by a propeller )

seriously, an integrated circuit( HT 2830 or 2844 ??? ) was recently sold, which animated the child's toys ... Helis, Fighters, etc ...

see here : http://www.temp.eleinmec.com/issue9.htm

Birds and animals too, with different chip suffixes !!!

Alain

Red 61

Aug 12, 2005, 10:33 AM

Hi, Guys

Do you have a little idea of the amplifier power and speaker weigh you need to make something "ear-able" :confused:

Seems the answer is NO ...

AlainActually, with an electrical engineering degree, and 15 years of work experience, I DO understand how to make something "HEAR-able". But thanks for asking... :rolleyes:

Acetronics

Aug 12, 2005, 02:25 PM

Actually, with an electrical engineering degree, and 15 years of work experience, I DO understand how to make something "HEAR-able". But thanks for asking... :rolleyes:

:D That was not really a question ... I've had a good experience with my model boats ...

Alain

vintage1

Aug 12, 2005, 05:51 PM

Hi, Guys

Do you have a little idea of the amplifier power and speaker weigh you need to make something "ear-able" :confused:

Seems the answer is NO ...

Alain

Yes. A lot less than it takes to power an aerplnae, and, depending on the frequencies you want to reproduce, between impossibly heavy to really insiginifcantly light...

Gary Warner

Aug 12, 2005, 06:30 PM

My idea for a motor noise generator.

Take a pager motor and attach a wire across the motor shaft (like a prop) and put lead (solder) "balls" on the ends of the wire. Place the motor assembly inside a "drum" so that the balls take a glancing blow at the surface of the drum. Use a ESC to control the RPM's of the motor, or if using a brushed motor, use a tapped motor voltage.

As the voltage increases, the pager motor runs faster. It could be fine-tuned to match scale RPM's (450-2600).

And, NO, I don't use recreational drugs. :D

Gary
--

skewbe

Aug 12, 2005, 09:19 PM

If you are going to generate noise electronically to sound like a slimer, may I ask that you use headphones? :)

I think some of the geared motors make a pretty cool sound fyi.

Red 61

Aug 12, 2005, 10:16 PM

Gary -- what's a "pager motor"? :confused:

Skewbe -- I'm not looking for slimer noise -- I'm looking for GUNFIRE! :D

Acetronics

Aug 13, 2005, 05:32 AM

Hi, red

:o you've chosen the most energy needing kind of sound ... most important air displacement = BIG loudspeaker too ... high weight too !!!

without me ... good luck !!!

Alain

Acetronics

Aug 13, 2005, 05:38 AM

Hi, KSU

When I was young ... there was a plastic F104 plane kit from the US, sold with an engine sound feature.

It was done by a small electric motor, running a gear on its axle, the gear teeth were placed into a slot cut into the fuselage.

This gave not too bad an engine sound ...

Why not try it ???

Alain

Leftyretro

Aug 13, 2005, 12:01 PM

If you are going to generate noise electronically to sound like a slimer, may I ask that you use headphones? :)

I think some of the geared motors make a pretty cool sound fyi.

LOL :p :p

Lefty

Red 61

Aug 13, 2005, 01:19 PM

without me ... good luck !!! :rolleyes:

Acetronics

Aug 13, 2005, 01:36 PM

Hi, Red

I'd be really very pleased to hear a recording ...

Alain

Photon

Aug 22, 2005, 03:38 PM

Did anyone check out the RAM products?
They have various engine sounds and machine guns.
http://www2.towerhobbies.com/cgi-bin/WTI0002p?&M=RAM

They seem rather heavy, at around 3 oz, but perhaps if you can find a lighter speaker ...

Red 61

Aug 22, 2005, 04:22 PM

At the moment, here's the route I'm going... Go to http://www.talktometreatball.com/, and click on products. There's a "Talk To Me Pet Tag", which is small, lightweight, and works on button batteries. I plan to purchase one, take it apart, add my own high power (tiny) speaker, and record my own sounds.

I've spent some time in the last few weeks trying to find something I can record to. Hallmark USED to sell recordable gift cards, but it seems they are no more... The "Talk To Me" line has lots of recording devices for pets (go figure).

Photon

Aug 22, 2005, 04:31 PM

Can you post a sample link to a "high power (tiny) speaker" ?

Red 61

Aug 22, 2005, 05:00 PM

Sure -- just take a look in the first post of this thread. http://www.regalusa.com/high_power_miniature_speakers.html

I currently have two of the RH-16-E speakers. 73 decibels at .3 watts, 16mm by 3.5mm, and 1.8 grams per speaker.

High power, lightweight, small size speakers! :D

Photon

Aug 22, 2005, 05:20 PM

Thanks. I missed that in the first post. It might be a good idea to simply take apart an old cell phone for its speaker.
Perhaps I can find a broken one in one of the cellular service stations, and try to ask them to give me one.

Red 61

Sep 14, 2005, 11:11 AM

Okay gang -- I have a working circuit. I don't have my camera with me at the moment (I'm at the office), so I'll have to post a picture later.

Here's what I did:

1) I downloaded several "machine gun" sounds from the internet, and chose the one attached to this post. (Well, okay -- I can't seem to upload the 300k file here... PM me with your e-mail address for the file, and I'll e-mail it to you.)

2) I purchased a recording module from Radio Shack (http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&product%5Fid=276-1323) ($10.49).

3) I recorded the "machine gun" sound from my computer speakers by holding the recording module about a quarter-inch from the left computer speaker. Luckily, the recording module records 20 seconds of audio, and the machine gun sound is exactly 17 seconds long!

4) I tried to use the RegalUSA speaker (R-H-16E (http://www.regalusa.com/high_power_miniature_speakers.html)), but the speaker is just too small, and would not produce enough volume. I tried the speaker which came with the Radio Shack recording module, but it was also too low in volume...

5) I tore apart an old computer speaker system to salvage the internal amplifier. The amplifier says it wants 9V AC, but 9V DC works just fine (though you do lose about 1.4 volts across the rectifier bridge -- I can bypass the rectifier bridge later; remember, this is a first try). The amplifier has a left and a right channel; I'm only using one of the two channels -- perhaps I can get more power with two speakers (I had not thought of that until just now)...

6) The result is amazing -- a very loud gunfire circuit. It currently weighs a porky 3.2 ounces (1.5 ounces without the 9-volt battery); I can lose some of that weight by removing the heafty on/off switch, the heafty potentiometer (volume control), and the power port (I already bypassed it by soldering the wires directly to the circuit board anyway).

I will need to put this circuit in my aircraft (probably my Slow Stick to test with), and attach a servo to the trigger button -- but things are looking REALLY good. :)

Red 61

Sep 14, 2005, 12:33 PM

I just did a little more soldering -- I removed the power jack and the heavy on/off switch. I soldered jumpers to bypass the on/off switch, so if the battery is plugged in, it's on. I soldered some jumper wires between the two power inputs of the two circuit boards (amplifier and recording module) -- it's officially one circuit now. :)

Current weight is 1.3 ounces without the 9-volt battery -- 3.0 ounces with the battery. I'm not quite sure how to remove this potentiometer... At full volume (0 ohms), the playback is distorted -- if I remove the pot, I'll have to find a resistor that's just the right value to be loud without clipping the output signal...

Does anyone have a source for battery holders for 3 button cell batteries? I'm thinking I can save a BUNCH of weight if I can ditch the 9-volt battery and go with button cells (watch batteries).

I will stop by Radio Shack to see if I can purchase another speaker -- to see if I can double the volume... :)

Photon

Sep 14, 2005, 12:41 PM

That "sounds" great. :)

You can also try a 3S LiPo. After the bridge voltage loss, you should be around 9V.

Regarding the volume, you can use 0 ohm, and do some recording tests at different volumes to make sure recorded signal is below cutoff range with amplifier.

What speaker did you end up using? Was it the PC speaker?

KSU Flyer

Sep 14, 2005, 12:46 PM

Red,

Play with the pot until you've arrived at a volume that does not distort the sound significantly, then measure the resistance of the pot. Find a resistor as close as you can to what you measured accross the pot, and then replace it.

-Mike

Red 61

Sep 14, 2005, 01:05 PM

I went home for lunch to take a picture of the circuit in it's current state.

I ended up using the el-cheapo speaker which came with the Radio Shack recording device. The PC speaker would have been WAY too heavy (we're talking over a pound for the speaker alone)!!!

I can't use a 3s lipo because the bridge is only on the amplifier board -- the recording device requires 9 volts, and has no bridge rectifier. :( However, I was thinking an 8-cell NiMh battery would do the trick (if only I were flying with an 8-cell NiMh battery)... :rolleyes:

Yeah, I thought about measureing the pot after taking it off the board -- that's on my list of things to do next. :)

Red 61

Sep 14, 2005, 04:45 PM

The PC speaker would have been WAY too heavy (we're talking over a pound for the speaker alone)!!!Okay -- I retract my earlier statement... I actually measured the PC speaker, and it's 2.5 ounces. It's also 3.5 inches long, 2 inches wide, and 1.5 inches deep! I just don't see my flying this speaker any time soon... :rolleyes:

lowdive

Sep 14, 2005, 06:20 PM

got any flat surfaces?
http://www.thinkgeek.com/gadgets/electronic/6bd8/

although, it's doubtful that would work.

Pete H

Sep 15, 2005, 02:17 AM

Red61 and others,
If the flight batteries is 3S lipo you drop 0.6v/diode using 1n400x series diodes, so three in series will drop 1.8v, giving 9.3v. This should be fine for a 9v device. You would need to bypass the bridge rectifier as well. Conversly leave the bridge rectifier in and just add a single diode in series.
Have you considered piezo speakers? - no battery = less weight!

All the best

PeteH

Red 61

Sep 15, 2005, 10:45 AM

Hey Pete -- hmmmm... I had not thought of adding another diode to the circuit... I'd have to add three on the recorder board, and one on the amplifier board...

Just to be painfully clear, I thought diodes came in 0.7-volt and 0.3-volt varieties (silicon and germanium, respectively) -- is there such a thing as a 0.6-volt diode?

I think I'm currently using a piezo speaker -- it's the one which came with the recorder, and is very small and lightweight. I'll find out more about it when I visit Radio Shack to purchase another one for the other amplifier channel. :)

Red 61

Sep 15, 2005, 04:35 PM

LOL -- I went to Radio Shack today with the part number found on the back of the speaker... I could not find a similar speaker in the entire store. The manager looked up the part number on the computer, and it returned the description for the recording device!

Looks like I can't get this exact speaker, so I'm looking at other options. On the plus side, I *did* find a nice enclosure (http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&product%5Fid=270-1802) which may work for this project... Then again, I wasn't thinking about weight -- maybe a custom balsa box would be better...

JohnMuchow

Sep 16, 2005, 02:30 AM

Just to be painfully clear, I thought diodes came in 0.7-volt and 0.3-volt varieties (silicon and germanium, respectively) -- is there such a thing as a 0.6-volt diode?

Yes, but...
Most silicon diodes start at about 0.6V-0.7V but the big boys can start as high as 1.1V or so. The Schottky diodes start at anywhere from 0.35V to 0.6V and the germaniums at about 0.3V-0.4V.

The problem is that the forward voltage drop of a diode can vary quite a bit depending on how much current is flowing through it. For example, the 1N400X series has about a 0.6V drop at a few milliamps up to a 1.8V drop or so at 20A (pulsed). Check out the data sheets on Mouser's (http://www.mouser.com) or Digikey's (http://www.digikey.com) pages for the diodes you're considering using to make sure the v-drop is right for the current you'll be putting through them.

Pete H

Sep 18, 2005, 09:50 PM

John,

Thanks of the update regarding the voltage drop - I was not aware there was that much variation. Looks more like 1v / diode at 1A would be closer so Red61 will b\have to measure current to calculate required number of diodes.

Pete H

alex.guzun

May 19, 2009, 10:17 AM

maybe arduino will help better
is there any sound library?

did you saw this?
http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=9031
http://www.benedini.de/Home_E/Products_E/products_e.html

Ron W3FJW

May 19, 2009, 04:27 PM

Hobby King has a sound generator for aircraft for around $125. Can't remember the details and can't provide a link as their server is too slow today.

Ahhh. Here it is.
http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=9031

OOps, already posted. Sorry 'bout that.

alex.guzun

May 19, 2009, 04:29 PM

it is the first link from my post (hobbyking is hobbycity)
but 125 is too much for this :(

Tomapowa

May 19, 2009, 05:15 PM

You also got this too... but I have not heard much from them lately... and with a perpetual out of stock status:

http://www.rcgroups.com/forums/showthread.php?t=828190

or

http://www.modelsolutions.ca/catalog_sound_systems.htm

alex.guzun

May 20, 2009, 03:34 AM

way tooo much :(
but nice

richg99

May 21, 2009, 08:12 AM

dmccormick001

May 21, 2009, 10:15 AM

One idea that has been discussed is to leave the heavy speaker and gear back at the flying station ( or with the pilot) and only transmit (by radio) the prop/engine speed signals back.

That way, the pilot and those close to him would hear the engine/prop noise ..but no one else would. Anyone have a solution that would work for that arrangement???? Rich
I'm trying to figure out exactly how this would work...how would you get the "doppler effect" from this arrangement? If the model is transmitting the sound back to the pilot's position, wouldn't it just be a constant engine sound, with no softer/louder rise and fall of the pitch or sound? To get the same effect, the system would have to know somehow when it's getting close to the pilot's location and increase/decrease the volume and pitch to make it sound like it's passing by, a very complicated task, I would think. Otherwise, all you'll get is a constant engine drone, which you could just as easily get with a tape recorder placed near you.

Hey, I just had a light-bulb moment. A tape recorder with engine sounds, and one of your buddies running back and forth behind you. You could train him to adjust the volume, too. Now that might work......... :D

Ron W3FJW

May 21, 2009, 02:39 PM

Got an even better RC idea. Put the tape recorder in a 1/10 or 1/8th car or truck & train one of the kids to run it back & forth. Keep the kids out of trouble & out from under foot that way. :D

shuttercat

May 30, 2009, 08:17 AM

Sound playback with Arduino alone is a little sketchy. If you want fancier sounds than nintendo blip-bloop, you're looking at something more like http://www.ladyada.net/make/waveshield/

But you'd be have to be running a larger model to cram that in there. Better to go with a number of short sound recording ICs like http://www.scary-terry.com/dsr/dsr.htm uses for Halloween decorations. I specked (but never built) museum interpretive material kiosks based on a chip like this for a class in college.

For remote sound, you'd need a means for tracking range (not my field) to the aircraft and then local sound playback could be doppler-shifted for rate of approach in software.

alex.guzun

May 30, 2009, 08:21 AM

yes yes, waveshield.. not arduino only ;)

valera_o

Jun 17, 2009, 09:11 AM

It's my sound module. Itself has made the scheme and the program.
Merlin's sound
http://www.youtube.com/watch?v=cIl_8GQ4pU0 (http://tpvelectronics.ucoz.ru)
DB601's sound
http://www.youtube.com/watch?v=zy4AtVD3zG8

valera_o

Jun 18, 2009, 12:19 PM

Lastest ;)
http://www.youtube.com/watch?v=0Bu7G-frBF0

valera_o

Aug 21, 2009, 02:15 AM

Depronator's BF109E with sound generator.
http://www.youtube.com/watch?v=_tLDPpIEvMQ

valera_o

Nov 18, 2009, 04:01 AM

My "gun" module.
http://www.youtube.com/watch?v=xyILE1_K8-E

dmccormick001

Nov 19, 2009, 08:27 AM

Nice work, valero o, but this is a DIY forum. Your device is only available for sale on your website. If you're going to post information about it here, why not offer the schematic and/or programming information to others so they can build one too? Then when they have a neat project or a useful device they've designed, you can get the information from them to build one yourself. Just a thought.........