How to build a cheap FM BUG transmitter

[theaviator2180]

please reply back with a link to get the air trimmer... you said its everywhere online but i have yet to find it in stores or on line, the only thing i can find is 3 prong potentiometers... please help!!!

[98mannus]

can you turn an old fm radio into a transmitter? pleas answer

[98mannus]

@98mannus and use it on an computer?

[jan777333]

where can i buy 22n axial ceramic capacitor?

[ITBelele]

hello, i`ve tryed to build a bug like in your video but instand of a 1p-5p to 30p trimmer i used a 5p-15ptrimmer with 3 legs and i used only 2 of them and i didn`t used the 22n capacitor you use after the coil AND when i plug the batteries ALL HEATS UP specially the coil and batteries you know why? ..i saw you said + of the mic ..wich one is + ?

[tikimon1000]

about how much will this cost in $?



[zakku232]

where ican get this from?

ihave a radio and telephone is it have this?

[humblesnurp]

It works! Pretty nice too, i recomend getting a large air trimmer for this project.

[theaviator2180]

@dazaro3 can you send me a link, i cant find them

[leifvier]

hot cute girl!

[david99soad]

with the variable capacitor you can change the output frequency?

[theaviator2180]

where can i find the air trimmer?! its no where online at all...

[dazaro3]

@theaviator2180

Lots of them on Ebay, the UK site ,maybe on others

[TheRandomGamer99]

replacement for 360R? i cant find any... and Tom17nors it is 360R they exist

[dazaro3]

@TheRandomGamer99

Yes a 330R or a 470R will work just fine

[Tom17nors]

sorry but this resistor 330 is not connected with collector but with emiter????he?? And it is 330 not 360 ohms...

[7419635841635]

helloo, im making an fm transmitter but without the ceramic trimmer or the variable capacitor, im making it with coil turns , i did 4 turns with 0.5mm coil and with a 3mm diameter, i just wanna know the radio frequency ( MHz ) ? will it be enough? or not thanks!

[dazaro3]

@7419635841635

Try a 5 turn coil then if you have no pickup with your FM radio then try a 6 turn coil.

[7419635841635]

@dazaro3 yeah because with 4 turns it didnt work even when i try to spread between the turns. whats the differance between spreading between the turns and not ?

[yeboah5054]

please will it work, if i build it on a bread board?.

can i use another radio apart from a car radio?.

can i use something in place of the trimmer?

[kruska811]

can i use 43 p trimmer??

[wiiawesome321]

The reason people use pcbs are to oranize what they made in a small space. Those wires could easily short out by touching another wire accidentally when a pcb wont

[alfadoscharlie]

good video, greetings from latina america!

[MagellanBarreto]

Muito bom !!! Ótima "aranha" (spider) !!!

[MagellanBarreto]

Muito bom ! Ótima "aranha" (spider) !!!

[sankethnoolee]

hey can u tell me how to tune the frequency of my transmitter??

[DjCaprious]

Pretty cool video. Pretty informative, actually. But god damn do I hate chip music...especially when it repeats.

[ozkr09013]

Awesome vid....A got a question, which is the frequency of transmmision???

And does it use any circuit of reception???

[ronald3729]

can i use any air trimmer?

[specialhitech]

there are fm receiver entering the ear canal completely, looking for micro earpiece fm receiver on Google from phontek

[nidees23]

there are lots of other bullshit videos

but yours with the explanation and example is fantastic

[justlivemyway]

I have work for you. Its regarding building an 8 channel RC remote using cheaply available Chinese 2.4 Ghz RF transceivers. Some channels need to work on PWM.

I need an email ID to explain in detail. I can pay through pay pal.

Thanks

[imranali121]

very very nice video and good technology but plz tell me about that how to make a signal mic with only one frequency without wire plz reply......

[iiyung]

i use this diagram.

[missrapunzel22]

can you just tell me where did you got the circuit diagram from???just tell the link plz i need it,reply soon

[iiyung]

i think i made it right but i can't find fm rate :(

[maclin24]

can u please mail me d diagram at maclindso@yahoo.com

[necrosato]

how do you tune the frequency

[necrosato]

can i hook up a jack to plug in my ipod instead of the microphone

[dazaro3]

@necrosato

See my other video and i show how to make one with a sound input and not a mic.

[karagenan]

Where can i get a 22n axial capacitor? can i use something else?

[akshayd211]

@acmefixer1 ....shud I use 12pF or 22pf disk capacitor instead of the air trimmer ?? :O. :) plz reply....thanks a lot..

[dazaro3]

@akshayd211

Yes that will work ok ,then use the coil to change the FM frequency

[akshayd211]

@dazaro3 ...thanks a lot ..!!

but should but can i also use a 12pF or 22pF disk capacitor as @acmefixer1 said !! ??

[fooder331]

do i even need an air trimmer and if so what does it do and where can i find it ( i live in New Zealand )

[akshayd211]

@dazaro3 .....PLEASE TELL ME WHAT EXACTLY IS THE 5p to 30p AIR TRIMMER CAPACITOR ??

What shud i tell the vendor if i want to buy one ???????

[dazaro3]

@akshayd211

The type i use are miniature ceramic trimmers, they are single turn ceramic trimmer capacitors,

you can use a: 4.2-20pF Red or a 5.2-30pF Green.

[acmefixer1]

One other point. It is hard to see how the components are connected together. If you want more detailed pictures, search for FM wireless mic on instructables website.

[nkmundle]

Why did you copy your circuit from Tony Van Roon's website?

[dazaro3]

@nkmundle

I did not ,i got it from talking electronics website

many years ago

[nkmundle]

@dazaro3 anyway Friend, its your devotion towards electronics that matters most. Very good tutorial.

[silvestro771]

It looks very nice but I'd be grateful if you could give some additional infos:

1) what kind of oscillator is? Id does not look like a Colpitts, Hartley or Clapp oscillator! I do not understand why should it be an oscillator? I don't understand the theory of the circuit!

2) Why the frequency should be changed by mic ?

Please give every kind of references you have aout it !!

[acmefixer1]

@silvestro771 Colpitts, though it doesn't look like it. The 4p7 cap adds feedback to make it oscillate. The mic changes the voltage and the junction capacitance varies with voltage. This version is missing the mic preamp transistor that most bugs have. You will have to talk loud or be very close to the mic to get it to be heard. Search google for FM wireless mic schematic to see many more plans. For best results you can buy the kit with PC board for around $10.00 US.

[nick1f]

You made a mistake at 3:19. The antenna has to be connected to the collector, not emitter. The diagram is correct.

[dazaro3]

@nick1f

Sorry ,no mistake ,in the video when i put in the antenna you are looking at the back of the 2N3904 ,from the back of an 2N3904 the left pin is the collector.

[nick1f]

@dazaro3 You wrote on the comment over the video "I solder the antenna to the emitter side of the 2n3904 transistor". 

[dazaro3]

@nick1f

Wow ,you are right ,did not see that one! all fixed now

[Neale91]

Is the 4p7 cap. connected between the transistor's collector and emitter part of the oscillator circuit? If so, what purpose does the 22n cap. connected between Vcc and ground serve?

[acmefixer1]

@Neale91 The 22n cap bypasses the RF from the coil to the common or ground. It will not be stable if it is left out. The most difficult part with this circuit is tuning the variable capacitor to put the frequency at the right spot on the FM band. Also, if you will be within a few tens of meters from this wireless mic, then you don't need the antenna. The antenna causes problems with stability, the freq will change when you get near it. A short one is better.

[SuperBrownie66]

But the frequency won't be stable.

Nice video though.

[7419635841635]

i have a couple of questions:

1- can i use a resistance other than 330 ohm?

2-why not using other caps besides ceramic?

[acmefixer1]

@7419635841635 Ceramic caps are cheap and work good at 100 MHz. FM frequencies. The 330 ohm resistor can be changed but it will change the battery current and the frequency somewhat. The sound quality is not that great, the high frequencies will be muffled because this circuit does not have preemphasis. that is used in FM transmission. You can see more at sm0vpo dot com slash tx slash bug dot html.

[7419635841635]

@acmefixer1 thanks for the reply! one more question, where can i find the air trimmer or the variable capacitor i've looked everywhere ( fixing shops etc...) ! now i just need to know where to i have to get it from from a radio? a machine? thanks

[acmefixer1]

@7419635841635

You don't need the variable capacitor. You can use a 12 to 22 pF ceramic disk capacitor (costs $.25 US or so). Then instead of tuning with the variable, you use a toothpick to push between the turns of the coil, and bend them outward to raise the frequency. Just a little bit of bending will make a fairly large change. I noticed the coil had 8 turns. I think that may be too many, most FM bugs have about 5 or 6. But it's better to have too many and take one or more off.

[7419635841635]

@acmefixer1 Thanks for the reply! i just need to know where can i get a air trimmer or a variable capacitor! with ANY value, i looked everywhere! and i cant find it! i looked in electric shops, fixing places, NO SIGN of it!

[rockman142000]

how is the sound quality ???

[joebro391]

great video dude! what if I wanted to receive the signal on something other than a radio? I mean, what if I wanted to receive it on a custom receiver at a distance of like 30 feet? I mean, the distance is a matter of power to the transmitter, but what about a custom receiver? might you have a circuit or link to a circuit where I could find on that would be compatible with the transmitter in the video? Thanks buddy! -Joe

[charleshood97]

can i use a .0047uf ceramic capacitor instead??

[HUSTLEBANE]

what does the air trimmer even do

[Comando979]

Where did you get your 1 - 5p to 30p air trimmer from.

[kathodenstrahl45]

I built some transmitter with the BC557 and 33p Cap. it works!!!

[KevinDice1]

You can make it even smaller by getting a coin sized 3 volt battery rather than two AA's.

[SKEL45]

will a gimmick cap work

[riothero313]

Sweet, I keep finding these things all over my apartment and now I know what they are. Thanks!

[johnqsample1]

instead of connecting a mic ,could i use auxiliary?

[tails2fan]

ITS SO TINY!

[theaviator595]

so i dont understand the coil part can you please explain the exact size and gage of the coil??? thanks!!! :)

[jerrycantrellfan15]

How many Henrys is that coil. I'm trying to do a simulation of it and I can't get it to work. Would the transmitter play my songs from an ipod if i switched out the mic and put my ipod on?

[NgtsCiduree]

It works!! Many thanks:)

[theaviator595]

for the 22n axial ceramic capacitor, is there anything else we can use? i cant find that anywhere :(

[rodwynnejones]

@theaviator595

22n ceramic disc cap will work or even radial. The word "axial" or "radial" just specifies how the leads of the cap actually exit the component itself.

axial = one lead exits from each end, like a resistor for example.

radial = both leads exit the component at one end.

[theaviator595]

i cant tell where the 22n capacitor is going.... :/ it just says now in

[andiukas223]

can i use somethig else for the 4.7p cap ?

[rodwynnejones]

@andiukas223

I've tried values from about 2pf to 10 pf, although it did work, it did work better with the 4.7pf. (I even got it to work without that capacitor in place).

[andiukas223]

@rodwynnejones so which one should i use instead of 4.7cap

[dazaro3]

@andiukas223

Any cap near the same value will work ,like 10pf 20pf

[prence1725]

@dazaro3 Sir, can i crap the inductor around a pencil 8 time?

[dazaro3]

@prence1725

O yes , no problem ,that will work just fine.

[jimsplokz]

@rodwynnejones

tnx men...

[Arapades93bmx]

can i put in state of a mic a mini jack?will it work?

[rodwynnejones]

@Arapades93bmx

you need to put a de-coupling capacitor in series with the jack to stop the "transistor DC biasing voltage/current" going into whatever you end up connecting to the jack, it also stop any input you use from altering the transistor bias, but how this would affect the rest of the circuit, i don't know. Might be better to use the two transistor version as it's much more stable.

[jimsplokz]

can i use more than 3V? as my supply?.. can i user 5v?... i want to build a radio transmitter.. and my player are laptop and my supply are the USB port it has a supply 5.3V...

[rodwynnejones]

@jimsplokz

I used 9V and it worked fine,

[dazaro3]

@rodwynnejones

Yes 9v will work fine ,but you will need to replace the 4.7K resistor with a 20k one for the mic.

[KaratenKit]

Awesome Music!!!

[djaa2807]

You rock :) nice tutorial

[mikewenham]

I've just built this on PCB (stripboard) and i'm getting about 50 metres range I'm only using 3v though as per the diagram, I might try more.

It is extremely prone to detuning when anything is moved even slightly. It also dropped from 96.1 to 96.0 after a couple of minutes warming up.

Excellent for something so simple though. I might try something more sophisticated that's frequency locked next.

[dazaro3]

@mikewenham

Please see my other videos when i build one using 2 transistors ,much better range and much more stable

[rome877]

Does this extend the radio regulations law in the uk law ?

[ThePrudhviram]

can you tell me the code of 2n capacitor

[rodwynnejones]

@ThePrudhviram

It's 22n not 2n and the code is 223 = 22000 in pF, 22 in nF (obvously) or, 0.022 in uF.

[ThePrudhviram]

@rodwynnejones

thanks for your information

[rodwynnejones]

Although this did work, I found a much better circuit (sorry dazaro3). using two transistors.

Google search :- "ck200 fm transmitter pdf". To make a good coil with even spacing, wrap two lengths of enameled copper wire round a 3mm former, slide the coils from the former and separate the two coils (quite tricky).

FYI

I used a 20pf cap at the antenna and the antenna itself was only about 30cm long and was built on a 25x64mm 9 strips 25 holes stripboard.

[dazaro3]

@rodwynnejones

Please see my other videos using 2 transistors

[dazaro3]

@rightbrainthinking

Yes ,its the sound of the motorway ,the M5 motorway is less than 1 mile from me.You can hear a pin drop from

15 feet away.

[TRUPAC12]

Should it work if I connect it to the mobilephone earphones?

[jarednwells]

Good video. Small error, you say and typed collector while pointing to the emitter and visa versa. Common mistake,I always make view keys to help avoid this. Thanks for the good post.

[fooder331]

hey do you need an air trimmer and if so where can i find one?

[rodwynnejones]

@fooder331

google search "trimmer capacitors". Available as two or three pin types. Two pins of the "three pin type" are linked and should be treated as one pin. Hope it makes sense. (it will when you got one in you hand). Build it on a stripboard rather then a birds-nest style as in this video, much easier.

[ThePrudhviram]

hai, i think you made a mistake while typing as 'oil' instead of coil

[computerfreakDK]

HOLY FUCK THAT MUSIC IS ANNOYING......wuts the name of it?

[ivanpavaoratincevic]

Thats not 360R resistor...

[dazaro3]

@ivanpavaoratincevic

No ,its a 330R resistor ,a 330r or 360r works just the same

[crack1q2]

Nice! Do you think I can replace the microphone with a microphone jack to plug for example my ipod in?

[triplexiscool]

thanks for the video ...i wonder can we use electrolytic capacitors instead of ceramic ones ?

also are electrolytic ones available in 1n ?

and what is that 175 cm antenna ? looks like normal wire and the guy at the shop didnt know what it was .... stupid question but please help ...thanks

[Theonlyuj]

I put it on a RC car

[dvdclaus5]

the circuit board desing cant you just upload it on a website and give a download link?

[everettlamborn]

what are the matirals needed this is what ive got 1n ceramic copaciter mic 8 turn coil 5p-30p air trimmer 4.7p ciramic copaciter 2n 3904 tranzistor 22n axil copacitor 9v batory conector 175cm antana

[ColdSilentWinter]

Arrrrrrgggghhhhhhhhhhh!!! It won't work no matter what I do. Probably some parts are broken or something.

[jasonguyperson]

@ColdSilentWinter oh no, not a good sign... i'm about to make one myself.. what is the air trimmer he's referring to?

[Slovenija12345]

If you cant regulate BUG with trimmer you can move the coil .

It works great

[TheKaos90]

Well , now i need to inverse the circuit so it is a receiver , and i can have a high quality pair of walkie-talkies for .... free beacuse the parts i'll get from electric junk laying around in my "box full of broken stuff" :))

[pocholox8]

maybe if i change the 10mm mic to audio it could put ur songs to the radio

[pocholox8]

maybe if i change the 10mm mic to audio

[touchsmart0]

cool but next time should add video parts showing how

[acido08]

Where Did you Connected The Antenna?.... to the Emitter of The TranSistor or To the CollecTor Side?..... Because Base Form your Schematic Diagram The Antenna is Connected to the Collector Side Of the Transistor,,,, Tnx,,,,,

[karagenan]

Can i use 5p or 8.2p insted of 4.7p?

[jsmythib]

IIITSS AAALIIVVEEE!!!!!! sry..had to do it...very interesting animal you have assembled! Thanks for sharing.

[zhir96]

Where do i get these parts? this looks pretty cool

[jks2]

does it matte wich transistors i use? i have an old transistor clock radio, and i would liek to use the transistors out of that radio. (electronic stuff is new for me)

[mondays89]

How exact does the capacitor values have to be? What would be the effect with too much or too little capacitance? Thank you for posting this.

[thewii552]

does the antenna have to be that exact length, or can it be longer?

[lisn92]

would you be able to put a jack for an audio cable insted of a microphone? and then play music from your mp3/4 player?

[leonardo1480]

what could I use if I don't have a 2n3904 BC547 transistor? would a BC549B work with this?

[frank0067]

I need to know how to simple make high frequency radio waves pls

[istanbulTurki]

@frank0067 first you need a high frequency transistor like BFR91 5GHZ 300mW

[leknifmy]

I cannot get hold of a 22n axial ceramic capacitor or ceramic trimmer capacitor - 5.2-30pf. Can you help me out where do I buy from in UK?

[rodwynnejones]

@leknifmy

BOWOOD-ELECTRONICS.CO.UK,

FYI -

I used the 5.5-65pF trim' cap. ("Ceramic" is not specified in part list for this component)

The 22n can be radial or axial, (I used radial) makes no difference. Radial / Axial just specifies how the two terminal pins are locaqted on the cap'.

[thejimmorrisonfan]

@rodwynnejones nice man but can u explain me what is the difference between radial and axial because in the store they didn't knew what to give me...

[Lloydster07]

If you need some help with electronics... go to a group page on facebook called Learn Electronics Lessons and projects

[thejimmorrisonfan]

@Lloydster07 tnx man ;)

[elfrododo]

@leknifmy I have the same problem =( and WTF is an air trimmer!

[mondays89]

No offense but the music is a little annoying.

[devilidol]

to attach this to a computer portal am i supposed to use the bateries or will the jack provide the power???

[MrWaesh]

as 4.7pf is not available in my nearby stores, can i use 12pf, 12pf & 22pf in sires?

[rodwynnejones]

@MrWaesh

I've tried it with values ranging from about 10pf to 2.2pf, although it did work with all of them it did perform best with the 4.7pf. The values you mention does give about 4.7pf.

[zauraliyev367a2]

you should stop the music after 4:15 ...

[jacksonvile1]

I am novice in this area. which the distance of transmission of this device?

[johnlovejenet]

the enamel-coated copper wire is quite hard to find. is it really 6mm diameter? or maybe 0.6mm?

[rodwynnejones]

@johnlovejenet

6mm is the diameter of the coil, not the diameter of the copper wire used to make the coil itself (it's 0.5mm by the way). Look at the circuit diagram, all the info is there!!

[jwnordquist1]

OK out of all i could find, Will a 2N4401 work for this?

[ductape95]

In the description you say 360R resistor but in the video, you wrote 330R. which is it? also is R the same as Ohms or is it Kohms

[losparkour97]

i cant find the channel

[bjtaudio]

If you all want a fun transmitter, try a Belkin Tunecast 2 or 3unit and remove the internal attenuator network and fit an external antenna, and it will go hundreds of meters in stereo, PLL locked on to station! no drift and digital read out of the frequency. Yon can use the same 547 transistor and parts above as an external amplifier..to go even further...

[bjtaudio]

Yea, I made one of these and it was fun, however they suffer from sever frequency drift, and as the unit is moved and the antenna moves, it changes the load on the unbuffered single transistor oscillator circuit changing the carrier frequency. Also battery voltage and temperature and component tolerances affect the carrier stability.

[dazaro3]

@bjtaudio

To make stability a lot better you need to add a

2nd transistor has a buffer,or use a 2nd transistor

and a inductor to make a RF output stage this will make

stability very good.With the 1 transistor FM transistor you just made add a 10pf

capacitor to the transistor collector and the other end to the

antenna ,this will help with stability when going near the antenna.

To learn lots on this type of device please visit talkingelectronics

and click the link for Spy Circuits

[1xDRCx]

if your having trouble finding the capacitors, you should convert their values. a simple conversion table is like this:: uf nf pf ::to convert capacitor values, you move three decimals, in the direction you need to convert so for a 1n ceramic capacitor, you start at nf, converting to uf, you move three decimals to the left so a 1.0 nf capacitor becomes a .001 uf capacitor, and a 22n capacitor, converted to uf becomes a .022 uf capacitor, both are at radioshack labeled as uf.

[dingoball]

Hey, thanks for getting me one step closer to surviving total apocalypse!

[PhatH0tG33k]

Does anybody know a place that carries most if not all these parts? I really don't want to have to order from three different places. Plus all the shipping. Thanks

[rodwynnejones]

@PhatH0tG33k

Try bowood-electronics.co.uk

[PhatH0tG33k]

@rodwynnejones thanks