Hello all, I'm in the process of building an electronic firing board for my fireworks show this year. Being my first semi complicated forray into building my own circuit, I am at a loss as to where to find some of my needed parts.
I have been to a number of different component retailers on the web and failed to find one component in particular. This is a cry for help.
The one thing I can't find anywhere for less than 35 bucks(way expensive I think), is a single pole, non shorting, 7 or more position rotary switch at least 5A@120VAC. I found one but it was sooo ridiculously priced.
Some of the other things I need for my project:
100+ - 50PIV diodes
3 - red panel lights, 12VDC 10-30A
8 - SPST Off (on) momentary push button switches 6A@120VAC
15 - 5mm LED's and chrome holders
3 - DPDT center off toggle switches 10A@120VAC
Aslo some assorted resistors and connectors I shouldn't have any problem getting most anywhere.
The sites I have been to:
http://www.allelectronics.com/index.html - good site with alot of the stuff I need, not the rotary though... seems like pretty good prices
http://www.digikey.com/ - their catalog is a pain in the butt to surf, and they seemed a bit expensive. hard time findin things I need, not familiar enough with manufacturers. I prefer a surfable catalog index.
http://www.bgmicro.com/ - their catalog is fairly ecclectic and unorganized, IMO, but they have a few things. small selection though...
http://www.jameco.com/ - nice web surfable catalog index, not an enormous selection, but not bad. prices seem ok. no rotary switch for me...
http://www.mouser.com/ - Huge catalog, siilar to digikey. Seemed a little easier to surf through than digikey. Their prices seemed average.
Those were about all I could find that would sell components in the small quantities I need. Now I need the experts around here to show this newb where to get the real deals... If anyone has a scoop on some rotary switches like I need, PLEASE let me know, I really don't wanna shell out 35 bucks a piece for 3 of em. I'll take links to any sites I missed, please...
Thanks for any help ahead of time!
I have been to a number of different component retailers on the web and failed to find one component in particular. This is a cry for help.
The one thing I can't find anywhere for less than 35 bucks(way expensive I think), is a single pole, non shorting, 7 or more position rotary switch at least 5A@120VAC. I found one but it was sooo ridiculously priced.
Some of the other things I need for my project:
100+ - 50PIV diodes
3 - red panel lights, 12VDC 10-30A
8 - SPST Off (on) momentary push button switches 6A@120VAC
15 - 5mm LED's and chrome holders
3 - DPDT center off toggle switches 10A@120VAC
Aslo some assorted resistors and connectors I shouldn't have any problem getting most anywhere.
The sites I have been to:
http://www.allelectronics.com/index.html - good site with alot of the stuff I need, not the rotary though... seems like pretty good prices
http://www.digikey.com/ - their catalog is a pain in the butt to surf, and they seemed a bit expensive. hard time findin things I need, not familiar enough with manufacturers. I prefer a surfable catalog index.
http://www.bgmicro.com/ - their catalog is fairly ecclectic and unorganized, IMO, but they have a few things. small selection though...
http://www.jameco.com/ - nice web surfable catalog index, not an enormous selection, but not bad. prices seem ok. no rotary switch for me...
http://www.mouser.com/ - Huge catalog, siilar to digikey. Seemed a little easier to surf through than digikey. Their prices seemed average.
Those were about all I could find that would sell components in the small quantities I need. Now I need the experts around here to show this newb where to get the real deals... If anyone has a scoop on some rotary switches like I need, PLEASE let me know, I really don't wanna shell out 35 bucks a piece for 3 of em. I'll take links to any sites I missed, please...
Thanks for any help ahead of time!
You should get the Mouser and Digikey paper catalogs, they are indispensable.
Why not use a cheap low-current 7-position switch to activate relays? Seems easier (and cheaper) than finding a rotary switch with such odd specs. Then you could probably source everything surplus.
Can I ask why you need mains voltage handling throughout your design?
Why not use a cheap low-current 7-position switch to activate relays? Seems easier (and cheaper) than finding a rotary switch with such odd specs. Then you could probably source everything surplus.
Can I ask why you need mains voltage handling throughout your design?
ACtually it's an all DC circuit.
It will run on two sealed lead acid, 12V 7A batteries hooked up in series. This will give me 24V @ 14A I assume?
The reason the specs are listed in AC is because that's how they were listed on the site I pulled the schematic I modified from. I'm no expert, just starting to learn my DC stuff. (I'm only on chapter 3 of the DC textbook I'm readin LOL)
Are you suggesting I should use a low voltage rotary switch(thus cheaper), in conjuction with an isolated low voltage power source, to activate relays to control my 24V? That seems like an okay workaround....
Thanks for the quick reply, I really appreciate any help and suggestions, I'm an electronics retardo....
I'll see about getting the paper copies of digikey and mouser's catalogs. Seems like that would be a LOT easier to go through.
thanks again
It will run on two sealed lead acid, 12V 7A batteries hooked up in series. This will give me 24V @ 14A I assume?
The reason the specs are listed in AC is because that's how they were listed on the site I pulled the schematic I modified from. I'm no expert, just starting to learn my DC stuff. (I'm only on chapter 3 of the DC textbook I'm readin LOL)
Are you suggesting I should use a low voltage rotary switch(thus cheaper), in conjuction with an isolated low voltage power source, to activate relays to control my 24V? That seems like an okay workaround....
Thanks for the quick reply, I really appreciate any help and suggestions, I'm an electronics retardo....
I'll see about getting the paper copies of digikey and mouser's catalogs. Seems like that would be a LOT easier to go through.
thanks again
faithblinded said:
Good, I was a little afraid that the mains was being run all over the place.
Ok. I'm guessing you just need sufficient current handling then, and the voltage spec was well over-rated.
Without knowing the schematic it is hard to say, I wonder how much DC current is really flowing. The one thing you must watch out for is that it is much harder to interrupt DC current flow than AC current flow, so don't under-spec those relays.
Two 12VDC 7aH batteries in series will be a 24VDC, 7aH supply. That's amp-hours, not amps. You could use half the supply to power 12V relays, or the whole supply to power 24V ones.
tiroth said:
Ok, well, the run from my board to the firing stations in the field will be over 100 feet, which is why my system is 24 volts instead of 12. At 12 volts my ignitors would take too long to fire.
here's my ROUGH schematic, im not up on all my notation, and this is just the firing panel, without alot of documentation, mostly just for my benefit. I'll have to draw up a proper schematic by hand and post it so I can get some pointers.
An externally hosted image should be here but it was not working when we last tested it.
Here's a link to my thread on another forum explaining that board a little:
http://www.diybuildergroup.com/showthread.php?t=89
http://www.diybuildergroup.com/showthread.php?t=89
I'm afraid I don't know anything about ignitors.
The Solomon stations are nice and cheap. There may be a better price than this:
http://www.mpja.com/productview.asp?product=4449+TL
There were also some deals on Hakko floating around the forum. For this kind of work, though, you really only need a cheap handheld. It won't hurt to get a good station, but you'll pay more.
The Solomon stations are nice and cheap. There may be a better price than this:
http://www.mpja.com/productview.asp?product=4449+TL
There were also some deals on Hakko floating around the forum. For this kind of work, though, you really only need a cheap handheld. It won't hurt to get a good station, but you'll pay more.
cool...looks pretty simple...too bad pyrotechnics are banned in Singapore...you need a license to have a fire show here...I suppose if you like challeges...you can come out with an SMPSU that will give you 24V out of a 12V battery...which will eliminate the need to lug arpound another battery...I can get 7AH 12V batteries for SGD$20 bux here...(Surplus) too bad shipping will probably kill you...
tiroth said:
Thanks! That looks like a nice station. I want to get a station because I plan on doing more and more stuff with it as time goes on. Come Fall I'll be going back to school(electrical engineering), so I want to have it. The more I learn, the more projects I'll come up with for myself. DIY till I die lol.
li_gangyi said:
SMPSU, not sure what that is?
Those batteries aren't too bad here either. Thanks.
Back to my primary concen then.
What online retailer will give me the best prices on the things I'm looking for?
Also, what amperage does a 12V 7AH battery deliver then? Not clear on exactly what an Amp hour is...?
Educate me wise ones.
Thanks to everyone for the quick responses and help. In just a few hours you have answered most of my questions and caused me to rethink my schematic for the better. Awesome! I like to save money! More to spend on the fireworks lol.
What online retailer will give me the best prices on the things I'm looking for?
Also, what amperage does a 12V 7AH battery deliver then? Not clear on exactly what an Amp hour is...?
Educate me wise ones.
Thanks to everyone for the quick responses and help. In just a few hours you have answered most of my questions and caused me to rethink my schematic for the better. Awesome! I like to save money! More to spend on the fireworks lol.
I would guess you could get virtually everything from All Electronics.
Batteries are rated in amp-hours. This means a 1AH battery will supply (in theory) 1A for one hour before it is totally drained, 2A for 30 minutes, 0.5A for 2 hours, etc. In reality, these figures are usually extrapolated from a specified cycle time, so depending on the actual circuit the amount of usage will vary. Try to look up information on the manufacturer's web site, some batteries are better than others for cycle vs. standby use.
SLA batteries can supply a huge amount of amperage. If you draw too much current for too long a time, they will overheat, and explode. I am guessing that your design basically needs very short duration, high current pulses. Probably, you will get a lot of use out of a charge, and as long as you are using a design intended for SLA batteries of the rated capacity, you will be fine.
Just remember that you should never let the battery voltage fall below the cutoff threshold or you will severely reduce your battery life. There are plenty of threads related to proper use and charging of SLA batteries.
Batteries are rated in amp-hours. This means a 1AH battery will supply (in theory) 1A for one hour before it is totally drained, 2A for 30 minutes, 0.5A for 2 hours, etc. In reality, these figures are usually extrapolated from a specified cycle time, so depending on the actual circuit the amount of usage will vary. Try to look up information on the manufacturer's web site, some batteries are better than others for cycle vs. standby use.
SLA batteries can supply a huge amount of amperage. If you draw too much current for too long a time, they will overheat, and explode. I am guessing that your design basically needs very short duration, high current pulses. Probably, you will get a lot of use out of a charge, and as long as you are using a design intended for SLA batteries of the rated capacity, you will be fine.
Just remember that you should never let the battery voltage fall below the cutoff threshold or you will severely reduce your battery life. There are plenty of threads related to proper use and charging of SLA batteries.
the batt voltage should never drop below 11.8V...max at 13.8...I suppose you could add a simple comparator and a volktage reference to shut the whole thing down if the batt runs low...thus eliminating the need for a expensive voltmeter...and yes you need 30V contacts...but they are tough to find...just go with standard 230V 110V relays...shouldn't be a problem...watch the current rating though...
Each ignitor will take 80 mA or less to fire, but the power runs to them over 100ft plus of 18 guage wire, and when firing 3 or more cues at once from that distance, only with 24 volts will they fire almost instantaneously.
As far as using AC relays go, what current rating should I go with, since my system will probably never pull more than a few (3 or 4) Amps?
As far as using AC relays go, what current rating should I go with, since my system will probably never pull more than a few (3 or 4) Amps?
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