Cylindric Ultrasonic Bat Detector

African heart-nosed bats can hear the footsteps of a beetle walking on sand from a distance of more than six feet. – [Amazing Bat Trivia]

That’s really got nothing to do with echolocation (the sonar system used by bats) or the device I’m about to describe, but it’s a pretty stunning piece of trivia.

Bat’s are fascinating creatures and here in Melbourne they are a common sight. At dusk streams of grey-headed flying foxes leave their camp in the Royal Botanical Gardens to plunder fruit and nectar from suburban flowering gums. The number of urban bats have swelled in recent years, giving the impression that the grey-headed flying fox is thriving, but in reality Australia’s bat population has decreased by 30% over the past decade. The increase in urban bat colonies is the result of ongoing destruction to the bats native feeding grounds. The Melbourne Royal Botanical Gardens is now the only breeding colony of grey-headed flying foxes in the state of Victoria. In 2001 the Royal Botanical Gardens started shooting these animals in an insane attempt to curb the local bat population. Thanks to public outcry and a dedicated group of protesters this practice was stopped. The grey-headed flying fox has since been classified as a vulnerable species by the Australian government.

I was once passed by a grey-headed flying fox while travelling down a deserted Punt Road at 2 am. The bat had a wingspan of about a metre, it was a mesmerising and beautiful experience. Yes, I’m quite a fan of this fellow mammal, however I’m not so obsessed that I go out at night with the specific intent of tracking them down; or at least I wasn’t until I discovered there was such a thing as a bat detector.

A bat detector is an instrument that will detect the presence of bats by tuning into the echolocation ultrasounds they produce. There are a variety of commercial bat detectors available but what excited me were the numerous internet sites with home-built detector circuits. I stumbled across these sites while trying to decide what to do with a 1968 Braun Cylindric T2 cigarette lighter. What resulted was the Cylindric Ultrasonic Bat Detector.

Cylindric Ultrasonic Bat Detector

My friend Gareth found the Braun Cylindric T2 cigarette lighter in a Canberra op-shop; it’s a stunning object. Designed by Dieter Rams in 1968 it was (according to this site) one of Rams’ favourite products. It is quite heavy, this particular version is chrome plated steel, but it balances nicely in the hand and the large black ignition button is a pleasure to use (in fact it’s oddly addictive, if I have the thing in my hand I often find myself obsessively pressing the button and I have to put the lighter down in order to stop).

braun lighter

Gareth gave me the lighter with the suggestion that I may want to turn it into something. I thought it would make a great something so I started searching for what that something might be. And then I found this site, and this site, and this one, and this one, and this one, (and the list goes on...) all of them dedicated to the construction of bat detectors. This is the sort of obsessive social behaviour I love, I just had to join in.

After looking at more than 15 different circuit diagrams I decided to tackle the Enhanced Simple Bat Detector design by Tony Messina. This design is based on two audio amplifier IC’s and a 7 stage binary counter. It’s a variation on Tony’s Simple Bat Detector with a few extra components to control amplifier gain and electrical stability.

ultrasonic circuit

The circuit operates as a frequency divider. Ultrasonic signals are collected by the transducer and amplified by the two LM386 audio amplifier chips. The signal is then fed to the CD4024 binary counter which divides the frequency by 16. Output from the frequency divider is passed through a variable resistor (for volume control) and on to a high impedance ceramic earphone. This circuit treats the ultrasonic waves as a series of binary pulses; it’s basically a 2 bit analogue to digital convertor, the wave is either on or off. The CD4024 counts (in binary) 16 pulses and then outputs a single pulse. The resulting sound is kind of like a Geiger counter, i.e. a series of clicks. As the amount of ultrasonic noise increases so do the number of clicks. The binary nature of the circuit means that the amplitude of the ultrasonic sound is not translated (the sound is either loud enough to trigger the counter or it’s not), hence the volume control is useful for adjusting the clicking noises to a comfortable level but it does not make a quiet bat louder (to achieve amplitude translation a different and far more complicated circuit like this one would be required).

Tony Messina has a useful list of parts suppliers here (he even lists Australian suppliers) but I had trouble finding a local source for the ultrasonic transducer he recommended. I decided to substitute it for a T/R40-16B (purchased from Jaycar for AU$4.95; part number AU5550).

ultrasonic transducer

This ultrasonic transducer can operate as both a transmitter and a receiver; I didn’t use the transmitter function. The specifications for the transducer give a centre frequency of 40kHz, this is a standard frequency for most ultrasonic devices and luckily it’s also a common bat frequency. Tony suggests de-tuning the transducer with a 6.8mH RF choke. When wired in parallel across the transducer the choke flattens the transducers frequency response. The transducer will be less sensitive at 40kHz but will have a larger frequency range (possibly as great as 20 to 50kHz) and will respond to a wider variety of bats. Unfortunately introducing an RF choke caused my circuit to oscillate so I left it off (it may be a problem with the type of transducer I’m using). I also omitted the stability components (the 10 ohm resistor and 50nF capacitor) from the amplifier IC’s because of problems with oscillation; and I removed the 220uF power capacitor because I ran out of space inside the lighter (With the 220uF cap. removed you could also omit the 220 ohm resistor, mine was already soldered in so I didn’t bother. The missing components are shown greyed-out in the circuit diagram above).

braun lighter disassembly

Disassembling the lighter took a couple of minutes; there were just two screws holding it together, it’s a very impressive design. With the fuel tank removed the lighter was a hollow shell; I needed some kind of internal structure to mount the circuit and switch assembly. I turned to my boxes of miscellaneous crap and I found this.

Canon ink cartridge

Actually I found 12 of them. I wouldn’t call myself a hoarder but I guess I have to ask myself just how many spent ink cartridges do I need. Right now I just need one.

ink cartridge in lighter

The ink cartridge wedged firmly into the lighter’s shell and by inserting a metal tag into the cartridge’s outlet I was able to screw it in place. With the cartridge installed there is just enough space to slide a 9V battery down beside it. Opposite the battery I mounted an extra large micro switch. The micro switch is positioned under the lighter’s large black button and gives a nice audible ‘click’ when pressed.

ink cartridge with electronics

I also installed a second switch in the circuit; a mini slide switch. Both switches can be seen in the above image. The micro switch is a momentary type and is designed for hand held operation of the detector. The slide switch is an on-off switch that provides for hands free operation (i.e. when the detector is sitting on a table).

When I started the mod I decided that I didn’t want to damage any of the existing components (in case I ever wanted to return the lighter to its former glory). This placed some interesting constraints on the mod. I wanted the bat detector to have; an exposed ultrasonic transducer, a headphone socket, a volume control, an on-off switch and a power indicator LED. Locating this functionality within Rams’ minimal interface design was at times quite a challenge.

transducer in bat detector

And at other times not. The installation of the ultrasonic transducer was totally straight forward, the existing flame outlet on the lighter seemed made to order (the transducer can be seen here set in black foam to isolate it from handling noise). Apart form the large momentary button on the side all other controls were located in the base of the lighter.

braun lighter base

There was a small hole here for refilling the lighter. It was too small for a standard 3.5mm audio plug but could accommodate a 2.5mm plug (with a few modifications to the plug). The problem with locating the headphone socket here was that I wanted the detector to work while sitting upright, in this position the base of the lighter has a clearance of only 2mm from the table surface. I needed a right angle 2.5mm headphone connector with a depth of just 2mm, not the sort of thing Tandy have lying around.

2.5mm audio plug

So I attacked a standard 2.5mm plug with a file,

modded 2.5mm audio plug

and ended up with this.

cut down switch

I had to do similar mods to the slide switch and LED, cutting and filing them to fit the air vents in the base of the lighter.

volume knob

For the volume knob I reused the lighters flame control dial. With the help of some heat shrink tubing I attached a squashed aluminium rod to the dial.

volume pot

The rod passed through the circuit board and into the centre hole of the volume trim pot.

bat detector circuits in lighter

Here you can see the battery, ink cartridge and switch assembly being fitted.

circuits packed together

With everything installed there was very little space left over.

bat detector2

The completed bat detector is almost identical to the original Braun lighter. The only visible difference is the ultrasonic transducer on the top,

detector lying down

and the controls I’ve added to the base. It even weighs about the same.

And it actually works (I’m always surprised when that happens). If you don’t have a bat on hand you can test a bat detector by pointing it at fast-running water; just turn your kitchen tap on full and start the detector. The faster the water, the more ultrasonic sound produced.

slave exhibition

The bat detector has just spent 3 weeks at VCA gallery in an exhibition called slave curated by Christopher LG Hill, Kain Picken, Rob McKenzie and Nick Selenitsch. (No bats were found).

Update 17th September 2009:

Steven has been experimenting with the circuit (see the comments) and reports to have increased sensitivity by adding a 0.1uF capacitor from the amplifier stage (Steven has connected to pin 1 on the binary counter) to the potentiometer. He reports:

here is the picture of the cylindric bat detector i made from the cylindric bat detector site  i spread the parts out a little so theres less likely to be any interfearence . ive shortened the wires from the board to the jaycar electronics transducer so that eliminates the need to bround myself to the positive like i did and ive added a 0.1uf mkt cap from pin 1 of the binary counter to one of the pins i have the pot wires solderd to  works excellant have yet to do some outdoor testing  away from the suburb and  out in the bush

steven's bat detector

Nice work Steven, thanks for the update.

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  1. Posted April 12, 2005 at 2:34 am | Permalink

    Hot damn, that lighter is a beautiful piece of work. It reminds me of my dad’s favorite Edward Gorey cartoon: an inventor and a patent examiner are standing by the open window in the patent examiner’s office, holding a contraption with a fat cord coming out of it. “You call this a death ray?” says the examiner. “Why, it doesn’t even slow ‘em down!”

  2. Liam Fennessy
    Posted April 30, 2005 at 3:20 pm | Permalink

    Finally made it here – and I find this. Scott I have a friend who has designed a personal submarine made out of a 1978 honda civic turned upsidedown. He hasn’t built it yet – I am covinced that he will drown – we should talk about it sometime. The alternative vehicle realm is full of bizaaro modding. the other group that would be worth looking up are Survival Research Lab – war machines

  3. Posted May 15, 2005 at 11:56 pm | Permalink

    That is cool, may have to get (or make one for) my girlfriend! however its more likly than not to end up in a bright orange plastic case

    thanks for the circuit diagram

  4. ian
    Posted May 17, 2005 at 2:10 pm | Permalink

    man, there are a lot of supervillans who would LOVE to get their hands on that!

  5. Posted June 24, 2005 at 10:06 pm | Permalink

    Hi Scott,

    Love your bat detector. My editor wants me to cover it for the magazine I contribute to. Please drop me a line if you get a chance. It’ll be a fun article. Thanks! Bob

  6. Posted August 3, 2005 at 12:27 pm | Permalink

    Voila, love your personal bat detector and if I may, will add your site somehow to our wildlife info web page …but at this stage I’m just happy to find a group of people that may be able to help me with a similar problem. I need a noise detector.
    The problem: The Woodend (Ipswich, Qld. Australia) Flying Fox colony is currently harrassed on a regular basis by something. Since I cant hear who or what is keeping those poor animals awake all day… I would like to start finding out if someone is emitting some sounds the human ear can not hear, but Flying Foxes can hear. (It is worth noting that I have NO idea how well Flying Foxes hear, but I’m told that they do NOT use sonar, but have “better than human” hearing. )
    Its heartbreaking to see the poor Flying Foxes being harrassed by who knows what on an ongoing basis (this has been happening since late january and it is NOT typical bat behaviour) …so if anyone help this electonically and gadget challenged 59yo… it would be most appreciated.

  7. Posted August 5, 2005 at 11:25 am | Permalink

    Hi Eva,

    Your comment that Flying Foxes do NOT use sonar took me by surprise. I’ve been trying to listen to them with my bat detector and (either through wishful thinking or nearby running water) I though I was having some success. So I did some research and of-course your right, only Microbats use echolocation and the Flying Fox is a Megabat (apparently there is one Megabat that does use echolocation but it’s not found on the Australian mainland). I need to find myself a colony of Microbats.

    As for your disturbed Flying Fox’s it seems that a bat detector would be of little use. I found this site (run by the Ipswich local council) which states the Flying Fox’s “hearing range is similar to that of humans, making high-frequency sound inaudible to them”. Over at the Sydney Botanical Gardens site is an account of the actions taken to disturb the Flying Fox colony, these include sound, light and odour. It might be helpful to compare your bats behaviour to these descriptions. The only actions that seemed to produce a prolonged disturbance were deep percussive sounds (and even these have had little effect since 1998), so ultrasonics do not appear to be your answer. In this case a simple tape recorder may be useful, this will not extend your hearing range but it could be used to emphasise any low frequency sounds and help locate their source.

    the best of luck,

  8. Posted August 11, 2005 at 11:40 am | Permalink

    Hello Scott,
    Thank you so much for bothering to reply. Much appreciated. I’m aware of the two web pages you pointed out, and they are pretty useless and really, not enough research has been done with megabats in this area anyhow.
    Please keep listening to your bat detector, you may well be right and their hearing also incorporates some sonar… who knows.
    I’d love to get my hands on a bat detector, so if ever you know of anyone having a spare one, please think of us. In the meantime, microbats can live in the same area as megabats, (I know in the Ipswich Megabat colony there are also microbats… so maybe you ARE having some success but just haven’t located the correct source of the sound. Either way, I’ll cross my fingers for you.
    Cheers and thanks again

  9. Posted August 11, 2005 at 11:42 am | Permalink

    … just one more thing you may find of interest, but which has no scientific backing at all and which may well be wishful thinking on MY part. However, we observed the following during my time raising baby Flying Foxes:
    I raised one particular Flying Fox which, like my dog, heard my car approach very much earlier then any of my family members. SO (although I have no proof) I do believe they may have a much better hearing than currently given credit for. Agreed that this may not extend to hearing a dog whistle (which I understand to be in the sonar range??) but it sure was good. She became exited my car was still at least 300m away from my house, and the distance could even have been further than this, however, as it was just an ongoing observation and not an experiment. Family members noticing that the bat was regularly calling out to me well before I drove into the drive way was spasmodic and too frequent for coincidence, however, we never got it down any more exact than this. It is also worth noting that even the dog reacted slower to my approach than the bat, although it was a British Bulldog, which may well be in itself the explanation.
    Cheers again, Eva

  10. Posted August 11, 2005 at 11:54 am | Permalink

    Thanks Eva, what a great story!
    If anyone out there has a spare bat detector please contact Eva through the website.

  11. Posted August 11, 2005 at 7:04 pm | Permalink

    please give me information than ultrasonic and sensors
    thank you

  12. Geo. H.
    Posted August 16, 2005 at 1:18 am | Permalink

    Ingenious. But I mourn the loss of a fine design object.
    Hope your lighter was busted beyond repair when you got it.

  13. Posted August 26, 2005 at 1:14 pm | Permalink

    Now thats creative …even though I fail to see why one would need a bat detector.

  14. Posted October 10, 2005 at 9:47 pm | Permalink

    Hi Scott,
    One nice piece of project you’ve made there!!
    Will you drop me a line as I have something I’d like to ask you.


  15. Ryan
    Posted October 18, 2005 at 7:02 pm | Permalink

    Hi Scott,

    Nice piece of work. I am a wildlife ecologist and make regular use of ultrasonic detectors to detect, record and identify microbat echolocation calls. Yes, only microbats use ultrasonic echolocation but fear not, there are heaps of microbat cruising around the urban areas eating insects (although obviously there are greater numbers out bush). You may well have been hearing microbats via your detector. Through the detector speaker you can hear the calls as a series of rapid clicks. These clicks become more rapid and rise in frequency into what is called a ‘feeding buzz’ when the animal is closely tracking its insect prey, these clicks then usually suddenly stop when the animal has either missed the final stage of the inflight interception, or …it suddenly has its mouth full!! Most bats call in the range of about 20-70kHz in Victoria. Most adult humans can only hear up to about 15-16kHz, children up to about 20. Dogs can hear higher prob. up to about 40kHz I think. I have held a microbat in my hand when there was a dog nearby and although I couldn’t hear anything the dog pricked up its ears and wouldn’t take its eyes off the bat!! There is one bat species in Victoria that calls within our hearing range (down to about 10kHz) – we hear it as a regular high frequency (high for us but low for bats) pinging noise above the trees and roofs. Most people just assume it is an insect but it is the White-striped Freetail Bat, so named because it has a white stripe through its brown fur down either side of its body. No-one has worked out what the stripes are for and both sexes have them.

    One of the cheapest commercial bat detectors is available from Titley Electronics, the Anabat Detection system. See


    I am not an expert on megabats but there is a device for keeping birds and flying foxes out of fruit orchards which makes use of a series of speakers which emit irregular sounds, The Phoenix Wailer. The speakers are a certain distance apart so that the sound waves end up colliding over the orchard and creating a sound that some animals find disturbing apparently. It has been trialled at the Melb Botanic Gardens without much success. Perhaps someone is directing something similar at your colony?

    As for your flying fox, it may be that she is hearing the high frequency noises from your car engine. Grey Headed Flying foxes can actually hear up to about 54kHz, however high frequency sound doesn’t usually travel as far as lower frequencies so it would have to be pretty intense sound for her to pick it up at that range, or else she has great ears!!


  16. tom zaccagnini
    Posted February 4, 2006 at 12:35 pm | Permalink

    Hello ,
    This maybe a little off topic but do you still have the “guts” of the lighter, i have three of these lighters that leak gas,and would love to get some spare parts .
    Let me know if we can work something out .
    Regards Tom Z

  17. Posted February 12, 2006 at 5:17 pm | Permalink

    Hi Tom,

    Yes I do have the guts of the lighter. You can see the fuel tank and attached ignition system in the “lighter disassembly” photo above. When I got the lighter is was empty and I never got around to filling it before I took it apart, so it may not work. But then again it might, you are welcome to try it out.

    I’d be interested in swapping it for something. It doesn’t really matter what, something you don’t want anymore, maybe something broken but still a bit interesting. Send me something and I’ll send you the “guts”.

  18. Clement
    Posted February 23, 2006 at 5:35 pm | Permalink

    How can you used one transducer?Either you use transmitter or receiver transducer?

  19. Posted February 28, 2006 at 9:11 pm | Permalink

    Hi Clement,

    The transducer I used is capable of operating as either a transmitter or a receiver (you can check out its data sheet here). In my circuit it is only used as a receiver.

  20. Peter
    Posted June 4, 2006 at 6:07 am | Permalink

    That is one sweet job of fabrication! Kudos! I too own a Y2 lighter that leaks gas as fast as it goes in. A faulty rubber seal on the intake valve appears to be the culprit. best wishes to all.

  21. Posted June 10, 2006 at 9:54 am | Permalink

    Hello Scott,

    thank you for your technology-sharing Web pages and for your respectful attitude towards animals (two good things that don’t go often together).

    When I have some time I’ll try to duplicate your bat detector (the circuit, not the Braun-lighter embodiment). About twelve years ago my wife and I raised a baby bat (you’d call it a microbat, it was 3.5 cm long when we found it and 7 cm when we let it loose): I was very curious to know what kind of signals it was sending around.

    Bats are not very well known even by the academic establishment: we talked to a university researcher about our little creature and discovered that he knew nothing about the fast purr it routinely emitted when we took it on our hands, as an expression of pleasure and confidence, just like cats do (was like a cat’s purr replayed on a tape recorder at twice or more the speed) .

    As all animals, bats are extremely attentive to everything around them: no wonder Eva Newman’s Grey-headed Flying Fox can spot her car’s noise at 300 m. My suggestion about a possible disturbing agent for Eva’s flying fox colony is some underground work within 5 – 10 Kilometers, depending on the ground composition, as all animals are alarmed by ground vibrations.

    Lots of luck to you and your flying friends.

  22. Posted August 30, 2006 at 3:55 am | Permalink

    If you find some bats flying around you, you can have fun with them by tossing something in the air – they will dive after it to some extent to investigate it. (You’re not throwing it AT them of course!) I’ve done this many times with my dad, out in the country and when I recently told a very outdoorsy friend about it, he flat out did not believe me :-O

    I’ve been trying to find any mention of that silly (but true) activity on the Internet, and that’s how I found your very interesting site.

  23. Pat
    Posted September 23, 2006 at 2:23 am | Permalink

    I know this is a late posting, but I have some spare parts that Tom Z may be interested in, could you forward him my e-mail… Thanks.

  24. Ken Jerrems
    Posted October 9, 2006 at 8:34 pm | Permalink

    Hi Scott,

    Another late posting, but you have opened a tin of worms here. A very interesting project, it inspired me to jump onto eBay, and walla, I finally found a Braun cylindrical lighter. from Richard, a chap in Scotland.

    I bid a small fortune, and won the item. I am not into bats, so will probably leave it as a lighter. Each time I press the button, I will think of this article.

    What’s next on the drawing board, a metal detector maybe, could use a few nuggets after exhausting my eBay account.

    All the best,


  25. Ken Jerrems
    Posted October 13, 2006 at 5:30 am | Permalink

    Hi Scott,

    Have received Braun cylindrical lighter, purchased on eBay, but cannot figure how to dissassemble it. All visible screws have been removed, however, the mechanism refuses to slide out. Depressing the button did not help. What is the secret?



  26. Posted October 20, 2006 at 11:06 am | Permalink

    Hi Ken,

    My lighter had two screws: one right in the centre of the bottom, removing this screw released the black base and a fine mess filter that sits under it, the second screw was inside the lighter located above the button, with this screw removed the entire internal mechanism slid out (I think the button stayed in position while this happened, once the internals are removed the button just falls out).

    Braun did make a number of different versions of this lighter, so the take-apart details may vary.

    Good luck with it,

  27. awan
    Posted November 26, 2006 at 5:58 am | Permalink

    hi, i m also waiting to design for the metal detector. and having seen your articles its influence me for the project to go ahead. so pleas if have any new circuit idea can you help me to see for the new invention for detecting the machine. in the address
    good luck

  28. Posted November 29, 2008 at 3:34 am | Permalink

    We have the bats!
    Responding to the Environmental Health Emergency of the White Nose Syndrome here in NYState we are doing urgent bat surveys; bat walks and bat flights.
    We’d love to include your detector in an exhibition addressing this:Manhattan Lifestyle experiments in cohabiting with Bats. Will include a link nonetheless.

  29. Posted August 27, 2009 at 6:06 pm | Permalink

    i made this cylindrical bat detector but cant get it to work its dead silent and is it suposed to sound like hissing or white niose when you dont get any bats after you switch it on, and the jaycar electronics details with the transducer dont give details on which leg is positive and negative . so is it like that on leds short leg one polarity the long leg is the other , ive rechecked all the tracks to the circiut here but is the circiut here for thwe cylindrical bat detector corect are all tracks in the right position as mine still dont work or is this thing dead silent with no hiss or white niose till you pick up a bat signal .

  30. Posted August 28, 2009 at 1:33 am | Permalink

    ive made few experimental modidifications , first i ran a jump from pin 1 of the 4024 iv via a 0.1uf written as 104 to one of the 5 k pot matrix pins i used to run wires from the pot to and i grounded myself via a 0.1uf caopacitor from the positive input and this appears to increase the sensitivity, useing me body capacitance , so when im not grounding myself ikts just a low machine like niose and minimin sensitivity when i blow on the unltrasonic transducer but when i ground myself the sensitivity jumps and the whole circxiut senses my body and hands near the transducer when i move close to the circiut it responds more better and i can hear signals from unknown souce via the transducer and the machine sounds are gone to then at least a few feet from the transducer my hand in front of it seems to be detected as if the transducer is useing both the transmitt and receave fuinctions , at once like some kind of ultrasonic radar transmitt and receave type while at the same time adjusting its effects to my body position at certain proximity to it

  31. Posted August 29, 2009 at 1:24 am | Permalink

    Hi Steven,

    When there is no ultrasonic sound the device should be silent. Rubbing your hands together above the sensor should produce ultrasonic noise, but the best way to test it is fast running water – turn the kitchen tap on full, if you don’t get a loud hissing noise then the circuit is not working (the noise will change with water speed).

    I’m not sure what connecting pin 1 to the 5K volume put is doing, sounds like it’s introducing a feedback loop into the circuit, this could be activating the transmit function of the transducer however I think it’s more likely to be something like ground loop interference.

    Grounding yourself to the volume pot or the ear piece may add stability to the circuit (it does on mine).

    Also, the long leg on the transducer is positive – I’m not sure the transducer is polarity sensitive, but the short leg is grounded to the transducer shell.

    If you have intermittent operation try adding/removing/changing the 10 ohm & 50nF filters on pin 5.

    Good luck with it.


  32. Posted August 29, 2009 at 3:01 pm | Permalink

    ive just tested it in front of the tap but i got s ignal only when i allso ground myself to the tap besides grounding myself to the positive the sound was so low with the tap running that i could barley hear it but the circiut responds well when i blow on the transducer , so what frenquency this detects wind at i dont know but if air blowing over it can be detected then would that allso have untrasonic signals in it is my geuss and rubbing a small white foam block onto my wooden desk can be picked up from just over a foot away and nothing else dose when i rub it on the desk to so maybe if its generating some low unltrasonic wave inside the small sound it makes its hard to say what frenquency this circiut now receaves signals on, since ive made the small mofifications to it , i think it may respond as some kind of vibration sensor at certain frenquencys me blowing on it and a tiny foam block rubbing on the desk tapping on my desk dose not make anything and rubbing other things on the desk iether , only what i mentioned if i put my finger on the front of the transducer the circiut responds like its receaveing signals from my bodys aura and if i rub my finger on the lump of blue tac i have the transducer sitting on it senses the miniute vibrations that i cant hear with my ears very easy, as if its acting like a geophone detector

  33. Posted August 29, 2009 at 5:09 pm | Permalink

    in the circiut schematic the 2x 10 n or p ceramics were shaded out as when i read the details the biulder of that circiut was haveing some problems with them in the circiut so he shaded them and left them out but it made no difference so i put the resistors with there 10n caps back in but nothing i noticed seemed to be happening before i lernt hear its mean to be silent till a bat signal is detected , i allso ended up leaving in the first resistor with its 10n cap and the second i took just the cap out but nothing happened till i did a modification since reading the replies her,e i decided to put it back i have better improvements now , instead of silence i got backgroung cosmic white niose with a low sounding machine like signal comeing through till i ground myself to the positive, yes positive not negative as grounding myself to the negative did nothing and if the e feilds from my body has any play in it when i move closer to the circiut the whole thing just sounds like slient white niose and my hands being rubbed together pick up easy on it now , i see how grounding yourslf to it can play a part in inproveing the circiuts response , and i still have the 0.1uf mkt cap from pin 1 of the 14 pin ic to one of the pot legs really helps alot . it sounds like my electronic gravity wave detectors, which i receaved and recorded many signls through the white niose that came over it . and to link this to bat detectors some of my waveform readings are nearly amazeingly identical to that of a bat signal waveform i found on the net froma site , and my gravity wave detectors use a ceramic capacitor as a sensitive sensor , ive listened to bat sound recordings and they sound nothing like my gravity wave signal detector recordings but the waveform s of this one are identical to that on the net from a bat signal recording.

  34. Posted August 30, 2009 at 1:23 pm | Permalink

    i like to make a corection to one of my lines as for rubbing your hands to test the transducer circiut i just rub my fingers together instead as my orther hand is holding the 0.1uf cap atached to the positive gounding wire and the range of detection of me rubbing my fingers only on one hand is around 3 feet away now how far away do you rub your hands together to test it compared to the distance i held my fingers up to in testing mine as the sensitivity is pritty amazeing , ive allready started another circiut but this time im bread boarding it and throw in some modifications to try push this things sensitivity to the limit .

  35. Posted August 31, 2009 at 2:25 pm | Permalink

    ive done some more testing and its picking up my fingers being rubbed together more than 3 feet away now as i was with great dificulty streched my arm and fingers as far as i can while staying in close proximity to the circiut as i found that grounding myself to positive was only part of it i had to be close in ceratin proximity to get this amazeing sensitivity

  36. Posted September 2, 2009 at 9:49 am | Permalink

    that sounds pretty sensitive – well done. Noise from rubbing my fingers together disappears over about 2 feet (if I snap my fingers it’s a bit further). Upload some picks (to flicker or somewhere) and drop us a link.

  37. Posted September 3, 2009 at 6:29 am | Permalink


    I had this same lighter inherited from my father who was a great cigarette smoker. I’ve kept this item in my workshop (I build art objects and sculptures out of leftovers and scrap materials) for at least 35 years. The day came that I had a good look at it and decided that the beautiful Dieter Rams design could become a nice Jules Verne vintage spaceship. So I’ve done it. Please check the photo at
    or give me a suitable mailbox to send it – thanks

  38. Posted September 5, 2009 at 8:55 pm | Permalink

    i got my patner to stand several feet away in front of my bat detector and rub her hands together as i monitored for any response and i got it 6 feet away , thats very sensitive and allso ive found out that if i shorted my wires from the ultrasonic transducer when i made a box for it ,i can eliminate the need to ground myself to the positive via 0.1uf mkt capacitor. the sound on my circiut is silent white niose and it responds very sensitivity, now to find a bat to test it with. remeber i have a 0.1uf mkt box cap from the pin one of the 4020 ic to one of the pot pins where i have my potentiometer wires runing to. this makes it simple if a wire comes off i dont have to take the circiut board out to resolder it as i used matrix pins to solder them to . ill post pictures when ive finshed the pvc made circiut box im designing

  39. Posted September 6, 2009 at 3:06 am | Permalink

    some testing appears to be going well as when i piont the transducer directly at the 240 volts 50hertz ac light from about 20 feet away it senses the vibrating tungston ellement in that globe. 50 hertz i think is within the ultrasonic frenquency range so it sounds the same as mains hum it wont do the same if i piont it at an ac applience like a tv from a distnace with the same voltage and current flowing into it niether the fridge with 240 volts ac at 50 hetz so it would have to be senseing the tungston ellement vibrations in the light globe at 50 hertz within the ultrasonic frenquency range is my geuss. inside the house ac feilds flow everywhere so from 20 feet away and near another ac applience they dont seem be detected by the transducer so as they dont have a vibrating ellement in them like a house globe , more tests to do yet

  40. Posted September 6, 2009 at 11:07 pm | Permalink

    flicker what is it where can i upload pictures

  41. Posted September 10, 2009 at 12:37 pm | Permalink

    if you email me the photo’s I can paste them up here. Otherwise, you could upload them to a host site like flickr and put a link to them here.

  42. Posted September 12, 2009 at 1:24 pm | Permalink

    ive emailed you a picture of my cylindric bat detector scot did you get it ok

  43. Posted September 17, 2009 at 9:42 am | Permalink

    thanks Steven, I’ve added the picture to the original post. Good luck with your search for bats.

  44. Posted September 24, 2009 at 8:48 am | Permalink

    still no bats around to test it on it looks like ill have to hire a bat siute and do it myself. oh the lazy bats there never around when y a need them,

  45. Posted September 25, 2009 at 1:36 am | Permalink

    as for bat sonar while wearing a bat siute im sure i could pass off me thought waves as sonar

  46. Posted October 10, 2009 at 1:02 pm | Permalink

    i still take my bat detector outside at nights for a scan for any ultrasonic waves, but are suprized to find that i receave tiny crackle sounds as if ultrasonic waves are being generated by something else out there that we cannot see , and allso even when theres no wind to blow any tiny particle of dirt against the transducer, which i allso can hear as sounding like what i emagine as a tiny particle hiting the transducer i still hear these tiny crackles ,

  47. Posted October 11, 2009 at 5:08 pm | Permalink

    last night i tested my cylindric bat detector outside in the rain and to my suprize i can hear the sounds generated by falling rain , even though you can hear the rain hitting the ground and other things with your ears theres something else here that enables my ultrasonic detector to pick up . so its not just runing water that generates any ultrasonic waves .

  48. Posted November 4, 2009 at 9:35 pm | Permalink

    my bat detector seems to be picking up allso atmospheric ultrasounds to

  49. Posted November 6, 2009 at 8:44 pm | Permalink

    and before we can see some distance lightening here i was receaveing crackeling noises with my modified cylindric bat detector outside in the evening but if bats sound anything like that to the bat detector wait till the lightening comes it was loud cracks i hear then , its obvious now my slightly modified cylindric bat detector can detect or sense more than just bats , even though havent seen a bat yet to test it on.

  50. k.immanuel
    Posted June 28, 2011 at 7:32 pm | Permalink

    i have connected the circuit but iam not getting clicks instead a long beep when detected a 40khz frequency.where am i gone wrong . please help me out.

  51. k.immanuel
    Posted June 28, 2011 at 7:54 pm | Permalink

    and the circuit i connected is the cylindric ultrasonic bat detector which is shown above.

  52. Ogolloh John
    Posted July 6, 2011 at 11:01 pm | Permalink

    Thats cool bro, I need to get myself one

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  1. By Rajat Dhingra » T2 cigarette lighter on December 23, 2009 at 6:34 pm

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