I will second what others have already said here: I have a clock in a wooden (laser-cut plywood) enclosure, but:
* my HV PSU (http://jan.rychter.com/high-voltage-power-supply-for-nixie-tube-projects) has current limiting, so most faults in the HV section are handled gracefully, * the whole unit is powered from a 12V/500mA brick. I considered the safety issues, but then determined that it is *really* difficult to start a fire with 6W of power. And with most supplies having overcurrent protection you’d have to draw exactly 6W, a short would just trigger the protection and all you’d get would be the power supply turning on and off periodically. So, assuming that your wall brick is reasonably safe (hint: if it’s very cheap, it likely isn’t safe), a wooden enclosure should be perfectly fine. —J. > On 22 Feb 2015, at 06:03, Matt <[email protected]> wrote: > > True. A *good* (and I stress good) switched mode power supply will become a > constant current power supply when you exceed its capacity. So if you short a > 12 volt, 2 amp power supply, you will get no more than 2ish amps. If the UL > or CE listing is accurate, the power supply may get warm, but that should not > be a problem. So to be safe, buy a switched mode power supply that can > deliver no more than the amperage that you need. That way, if something > shorts in the clock, that is all the power it is going to get, which is > hopefully not enough to start a fire. To be sure, you may want to test this. > > Unfortunately, there are many power supplies on the market that are unsafe > for various reasons. Make sure to get one from a reputable source, or have > the power supply properly examined. Here are some articles and videos about > unsafe power supplies: > > http://www.righto.com/2012/10/a-dozen-usb-chargers-in-lab-apple-is.html > > https://www.youtube.com/watch?v=wi-b9k-0KfE > > https://www.youtube.com/watch?v=_exfmbsPqEI > > http://hackaday.com/2012/10/10/raspberry-pi-foundation-looks-a-counterfeit-apple-power-supplies/ > > https://www.youtube.com/watch?v=q9wKjZXDPWI&t=9m39s (USB power supply begins > 9:39 in, ends at 17:52) > > Also, poorly designed power supplies can add noise to your A/C line or RF > interference for nearby devices. Here is one power supply that mostly works, > but poor power filtering prevents a specific device from working (while other > devices work fine): > https://www.youtube.com/watch?v=8wkoxZw53Sk > > This video explains how a simple switched mode power supply works: > https://www.youtube.com/watch?v=bmtW_oA1fRo > > On 02/21/2015 09:54 PM, Jeff Walton wrote: >> Regarding your concern about the wooden housing: >> >> I had an old nixie design that I did in college in the 1970 timeframe. It >> used voltage doubler circuitry for the nixies and housed a filament >> transformer for the main power supply, which were all mounted inside the >> housing. My old design with point to point wiring and discrete devices is >> dark ages compared to current designs. That clock ran perfectly for over >> thirty years with a wooden and plexiglass case and was no problem - until >> 2005 when the voltage doubler shorted and caught fire. It had far more >> power available inside the housing when things went wrong. >> >> I think that the designs from present day with the external power supply >> (and limited energy) are quite safe to run with wooden enclosures. The power >> supplies are quite safe and if there was a problem with something, it would >> most likely not be with the clock itself. >> >> On Saturday, January 25, 2014 at 12:10:21 AM UTC-6, Michel wrote: >> >> I would feel a bit anxious to leave a wooden clock switched on for say 24 >> hrs/day, especially if it is not my own design. Just >> worried it would catch fire at a moment I am asleep or not there. Is that >> just me or do other people have that same worry? >> >> I quite like the design though, not an immediate "wow" factor as some >> other clocks, but I wouldn't mind having a clock like >> this one. >> Michel >> > > -- > You received this message because you are subscribed to the Google Groups > "neonixie-l" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send an email to [email protected]. > To view this discussion on the web, visit > https://groups.google.com/d/msgid/neonixie-l/54E9632D.8040400%40matthewc.net. > For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/CBFFA6C8-9417-4E1C-93D6-682FEFF103B0%40gmail.com. For more options, visit https://groups.google.com/d/optout.
