shortliner Posted December 30, 2010 Share Posted December 30, 2010 In a way back MR there was a circuit for building a battery operated, mech reefer, sound unit. I had a copy but have mislaid it - does anyone happen to have it please?TIA Link to post Share on other sites More sharing options...
AndrewC Posted December 30, 2010 Share Posted December 30, 2010 I think you may be looking for the Dec 88 issue of Model Railroad Craftsman. If you are lazy Aztec make one http://www.aztectrains.com/sound.html Its in HO but you can use the innards and sell on the Athearn Reefer it comes in. edit: oops, meant to say I can't find my copy either but will go hunting. Link to post Share on other sites More sharing options...
shortliner Posted December 30, 2010 Author Share Posted December 30, 2010 Thank Andrew - I thought it was in the "Electronics" section of MR before they dumbed down - but I might well be wrong Link to post Share on other sites More sharing options...
Prof Klyzlr Posted December 30, 2010 Share Posted December 30, 2010 Dear Jack, Dec 1988 RMC seems to be the conscensus http://www.trainorders.com/discussion/read.php?3,455281 Happy Modelling, Aim to Improve, Prof Klyzlr Link to post Share on other sites More sharing options...
Glorious NSE Posted December 30, 2010 Share Posted December 30, 2010 Battery powered so it can run on DCC tracks without interupting the sound! Batteries (#AG10) are included. Surely for DCC you'd be better track powering it and never having to replace the batteries? Link to post Share on other sites More sharing options...
bertiedog Posted December 30, 2010 Share Posted December 30, 2010 I have heard the Aztec version, and an O gauge version, may have been Weaver, and unless you are after a constant buzz, then I think they are not worth it. The Aztec one uses no speaker, but a sounder, and the sound suffers. A steady diesel type compressor noise can be done with a 555 timer circuit, but is it worth it, each reefer car would need one. Might be a case for an old fashioned recording running, or recorded on a sound storage chip, for replay over decent speakers, still the best way for steams sounds despite DCC sound, which is still very poor. Stephen. Link to post Share on other sites More sharing options...
shortliner Posted December 31, 2010 Author Share Posted December 31, 2010 Thanks Gentlemen - now to find someone who has access to a copy. - Possibly the Kalmbach museum Link to post Share on other sites More sharing options...
Prof Klyzlr Posted December 31, 2010 Share Posted December 31, 2010 I have heard the Aztec version, and an O gauge version, may have been Weaver, and unless you are after a constant buzz, then I think they are not worth it. The Aztec one uses no speaker, but a sounder, and the sound suffers. A steady diesel type compressor noise can be done with a 555 timer circuit, but is it worth it, each reefer car would need one. Might be a case for an old fashioned recording running, or recorded on a sound storage chip, for replay over decent speakers, still the best way for steams sounds despite DCC sound, which is still very poor. Stephen. Dear Jack, Stephen may actually be onto something here. Cheapo generic MP3 players are available via eBay for as low as US$0.99. (average prices are closer to US$5, which is still very do-able) That's low enough to fit within even my "replace with Kadees, metal wheelsets, and maybe replace some grabirons" budget/car. (particularly over a fleet of cars, it may well even beat a "home bruise' circuit in $$$ terms....) With a single decent MP3 recording of a suitable generator/refrigeration unit, and the automatic "loop play" function of the afore-mentioned cheapo MP3 players, they become very "set and forget", and will very likely be capable of "more recognizable" sounds than a basic "oscillator synth" circuit. (Not better frequency response mind you, but more "recognizable at a glance" audible effect). With the "user-loading" of the MP3 player, and a few seconds work in a free audio editor like Audacity, you could easily adapt the generator audio to suit the enclosure, speaker driver, any accoustic aberations of the reefer carbody, and "scale sound" volume levels. As for "track recharging", most of these MP3 players have built-in battery systems, charged from the 5VDC 100milliamp supplied by a USB port. A bridge rectifier, small cap, a LM7805 5VDC regulator, and some quick/dirty wheel pickups a la Harold Minkwitz's Kadee #5 centring spring pickups, should get things happening... Just thinking out loud, Happy New Years to all... (T - 90 mins and counting) Happy Modelling, Aim to Improve, Prof Klyzlr Link to post Share on other sites More sharing options...
shortliner Posted December 31, 2010 Author Share Posted December 31, 2010 John, thanks for the suggestion but the thought of trying to find a suitable sound file and download it to an MP3 player fills ne with horror - I can find my way around a 555 circuit, but actually boughy swmbo an MP3 player from hongKong. we spent about a week trying to understand, and make it do as it was supposed to, following the "Chinglish" directions without any success, and it then sat in a drawer for about 9 months, before being transfered to the local charity shop - I'm sure the idea is fine, but I really don't want to go down that route again, thanks! Link to post Share on other sites More sharing options...
shortliner Posted January 1, 2011 Author Share Posted January 1, 2011 Electroniic circuit wizards help requested Link to post Share on other sites More sharing options...
johnteal Posted January 1, 2011 Share Posted January 1, 2011 generator in mp3.. http://www.freesound.org/samplesViewSingle.php?id=98122 the freesound website has hundreds of mp3 files to download and play with. Link to post Share on other sites More sharing options...
bertiedog Posted January 1, 2011 Share Posted January 1, 2011 Electroniic circuit wizards help requested Without actually building it, the circuit should work, and give a constant buzz, frequency unknown till I work out the RC constant, but I assume about 300/400 hz and appears to be a sawtooth wave form. I will do one on a breadboard and check, but I cannot say this will satisfy as a generator sound, might work as a low frequency doorbell! Sounders are efficient, but a tinny thin sound and that circuit is stable, no variation at all, bland beyond belief ............ Link to post Share on other sites More sharing options...
bertiedog Posted January 1, 2011 Share Posted January 1, 2011 The values seem to calculate too 335 hz , which sounds right, I will try it and see what results. Link to post Share on other sites More sharing options...
bertiedog Posted January 1, 2011 Share Posted January 1, 2011 Re-checking its seems to be 155hz , about 1/2 of the previous calculation using an online calculator, a healthy buzz., and a sine wave form. Link to post Share on other sites More sharing options...
shortliner Posted January 1, 2011 Author Share Posted January 1, 2011 Stephen - if it does work, I shall be having to visit Maplins when they re-open - your input is much appreciated. Have a great New Year Jack Link to post Share on other sites More sharing options...
bertiedog Posted January 1, 2011 Share Posted January 1, 2011 This is the correct circuit for the 555, with the values, (nearest preferred), and it runs at 150HZ with a square wave output 50% cycle, about as simple a 555 as you can get, a buzzer! Cost ...pence to make, add a battery or a constant voltage mega capacitor circuit to power up from the track, (the constant lighting type would do it), or a regulator from the track power, and you too could have a reefer that sounds like an angry bee......... Link to post Share on other sites More sharing options...
shortliner Posted January 1, 2011 Author Share Posted January 1, 2011 We posted together Thanks very much Link to post Share on other sites More sharing options...
298 Posted January 1, 2011 Share Posted January 1, 2011 I have an 57' Reefer with an Aztec sound generator, and think i'll have a go at changing the sounder for a proper loud speaker as the factory unit produces the most annoying noise ever. In fact, I can imagine a yard full of the things would indeed be the most annoying noise ever, and will stick to silent cars. Link to post Share on other sites More sharing options...
bertiedog Posted January 1, 2011 Share Posted January 1, 2011 I have an 57' Reefer with an Aztec sound generator, and think i'll have a go at changing the sounder for a proper loud speaker as the factory unit produces the most annoying noise ever. In fact, I can imagine a yard full of the things would indeed be the most annoying noise ever, and will stick to silent cars. It may not work, unless a high impedance speaker , say 100 ohms, the remedy may be to modify the sounder with a small lump of blu tack! this will lower the audible output, and with a bit of experiment might improve it no end. Link to post Share on other sites More sharing options...
Prof Klyzlr Posted January 2, 2011 Share Posted January 2, 2011 Stephen - if it does work, I shall be having to visit Maplins when they re-open - your input is much appreciated. Have a great New Year Jack Dear Jack, 1 straight-line question, what make/model reefer boxcar are you intending to use for these cars? Happy Modelling, Aim to Improve, Prof Klyzlr Link to post Share on other sites More sharing options...
shortliner Posted January 2, 2011 Author Share Posted January 2, 2011 John - I was lucky enough to pick up half a dozen of these at an exhibition some while back at £2.00 each - just thought it might be fun to have them with sound At 57 foot they are longer than I would normally use, but thet may get used Link to post Share on other sites More sharing options...
Pinkmouse Posted January 2, 2011 Share Posted January 2, 2011 It may not work, unless a high impedance speaker , say 100 ohms, the remedy may be to modify the sounder with a small lump of blu tack! this will lower the audible output, and with a bit of experiment might improve it no end. Or perhaps try the drivers from cheap and nasty in-ear headphones that pound shops seem to have an abundance of. I have a set somewhere, I'll stick them on the meter later. Link to post Share on other sites More sharing options...
shortliner Posted January 2, 2011 Author Share Posted January 2, 2011 Following on from Johns MP3 player suggestion, on the Big Blue forum this was suggested http://www.shop4tech.com/item8627.html not the cheapest - but possibly useful Link to post Share on other sites More sharing options...
bertiedog Posted January 2, 2011 Share Posted January 2, 2011 Or perhaps try the drivers from cheap and nasty in-ear headphones that pound shops seem to have an abundance of. I have a set somewhere, I'll stick them on the meter later. Just shoved some on a meter and they are 10/14 ohms, a bit low for the direct connection to the 555, it would need a single transistor driver added to the output to balance the impedance. Mind you with a 50 ohm resistor added it would still buzz and that is what's needed. A single transistor stage would add hiss of course, a spot of white noise to add to the buzz. Link to post Share on other sites More sharing options...
Pinkmouse Posted January 2, 2011 Share Posted January 2, 2011 Lower than I would have thought, but checks with my measurement of 20ohm for the set I have here Like the transistor idea, though I'm not used to designing noise into a circuit... . Link to post Share on other sites More sharing options...
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