Tribe.net. Local Connections Zippi http://electronichobbyist.tribe.net/thread/0ea761db-37d5-4911-bc98-d1a08b195731 2009-09-24T18:14:50Z 2009-09-24T16:40:14Z

<div>I'm messing about with LEDs and power supplies. <br/> <br/>I'm not in the stage where I have any hardware. ( well I do have several low voltage lighting transformers left over from a renovation) <br/> <br/>I'm still trying to figure out how to do what I want. <br/> <br/>Take this: <br/>R = (VS - VL) / I <br/>where <br/>R = the resistor <br/>VS is the cumulative voltage demand of the LEDS in series <br/>I = the LED draw in Millliamps (Ma) <br/> <br/> <br/>For a series of 6 LEDs ( assume 2 VDC for each) I can take a 120VAC line voltage rectify it to DC and end up with : <br/>120 - 6 / 0.02 = 5850 Ohms resistance <br/>Does that make sense? I need a resister of 5850 Ohms?? <br/> <br/> <br/> <br/>Then on to the power supply. <br/>I need no less than the voltage the LEDS will draw down. <br/>So a 120 DC line will not drive more than 51 LEDs? <br/>Does that make sense? <br/>I can only drive 51 Two Volt LEDs on a 120 Volt supply line? <br/> <br/>I've seen systems where way more than 50 LEDS are running in a plug and play bank of hundreds of LEDs and the thing is sold to plug into a 120 VAC line. <br/> <br/>What am I doing wrong?? <br/> <br/>I'd started out wanting to use a single phase linear step down transformer and a bridge rectifier to get 12VDC. <br/> <br/>Would I be better off starting out with a 120 VAC line, feeding a series of Step down transforms each of which was rectified to DC ? <br/>The transformers I now have will yield 12Volts under load. <br/> <br/>The reason for converting to DC is to not have the LEDs in the OFF mode for the period between 60 Hertz cycles. It adds up over time to a cumulative loss in light output. <br/> <br/> <br/> <br/> <br/> <br/></div> <div> posted in <a href="http://electronichobbyist.tribe.net">Electronic Hobbyists</a> - 4 replies </div>

Zippi 2009-09-24T16:40:14Z Steamboat_Ed http://electronichobbyist.tribe.net/thread/4b23a393-7a43-492a-af51-b7288cfecef0 2008-11-01T04:20:03Z 2008-11-01T04:20:03Z

<div>Photos here: <br/>http://www.flickr.com/photos/38392448@N00/sets/ <br/>...and short video here: <br/>http://www.youtube.com/profile_videos?user=wanglydiaplt <br/> --If you have a yen to get into computer control I've posted the code on the Parallax message board..</div> <div> posted in <a href="http://electronichobbyist.tribe.net">Electronic Hobbyists</a> - 0 replies </div>

Steamboat_Ed 2008-11-01T04:20:03Z write_guy http://electronichobbyist.tribe.net/thread/23cc6ebc-2859-456e-834d-c9e1b02becfd 2008-04-19T09:37:37Z 2008-04-19T09:37:37Z

<div> <br/>Greetings <br/> <br/> <br/>I’m trying to duplicate the effects of "Lightning strikes units" in a budget for a no budget short. If you don't know what that is cool. But if you have watched any David lynch films and the actor is bathed in a flashing strobey light that is controlled this is them. A simple strobe light pulses to fast and is no good. The before mentioned LS units cost way too much to rent for an artist of my paltry means. It’s a little off topic but I have seen some wacky stuff for cars perhaps that’s a way to go? Any help thanks <br/> <br/>Duane</div> <div> posted in <a href="http://electronichobbyist.tribe.net">Electronic Hobbyists</a> - 0 replies </div>

write_guy 2008-04-19T09:37:37Z jeau http://electronichobbyist.tribe.net/thread/a0c41b0b-a111-45a0-ba95-57c97667e7c6 2008-02-08T04:21:52Z 2008-02-02T16:23:05Z

<div>Hi everyone...I'm trying to construct a gizmo that can best be described as an electric see saw. Basically, it's for mixing fluids using a rocking motion. I have considered other mixing methods, and for reasons too complex to bother going into, have decided on this design. <br/> <br/>First, picture a long box, about 10" by 30", that contains about a dozen cans of soda or small bottles all in a row, one level high, lying on their sides. The whole box must rock back and forth such that the contents of each bottle will slosh from the cap end to the bottom, and back (not from side to side). Picture a one-inch pipe running beneath the length of the box (yes, the long way), acting as a fulcrum. <br/> <br/>My question is, what do I use to motorize this? I know nothing about motors and other such devices, but need to make this electrified so that I can step away while it rocks itself for an hour or two as I prepare the next batch. Your brilliance is needed, thank you in advance!</div> <div> posted in <a href="http://electronichobbyist.tribe.net">Electronic Hobbyists</a> - 3 replies </div>

jeau 2008-02-02T16:23:05Z Steamboat_Ed http://electronichobbyist.tribe.net/thread/c3eb6de5-c77b-4e83-becf-e6b83a17f84a 2007-06-18T19:47:56Z 2005-11-20T01:45:18Z

<div>--Trying to figure out how to use a large-ish worm-drive windshield wiper motor behave like a servo; i.e. input a signal from a Stamp and have it turn the output shaft only so far. Anyone got a clue? <br/> </div> <div> posted in <a href="http://electronichobbyist.tribe.net">Electronic Hobbyists</a> - 21 replies </div>

Steamboat_Ed 2005-11-20T01:45:18Z sillydiego http://electronichobbyist.tribe.net/thread/20fd21a9-7fb4-4810-beff-edf6090240f1 2006-04-08T02:50:30Z 2006-03-23T03:13:17Z

<div>Sorry if you are seeing this as a crosspost from the robots tribe, I am a bit desperate for help! <br/> <br/>I need to strobe a batch of LEDs, ideally 200, and need to use my DMX system to do so. I have a dmx strobe control unit, however it is only designed to trigger strobe lights using a 10 volt square wave with maybe a total of 250 milliamps available before voltage starts to drop off, possibly then damaging the controller. <br/> <br/>250 miliamps will of course not drive a batch of 200 LEDs that will need, by my calculations, about 6 amps. (30ma x 200= 6,000ma) <br/> <br/>I have no experience with using transistors in a circuit. Is it possible to use a transistor in a very simple homemade circuit, triggered by the 10V square wave, to switch the LEDs from a larger power supply? <br/> <br/>Is the relationship between input and output voltages critical? If so, are calculations difficult? <br/> <br/>Also, I understand transistors have a frequency limit to their switching, I think most should have no problem switching at a max rate of 20 cycles per second, is that a correct assumption? <br/> <br/>Any advice you guys can give would be greatly appreciated.</div> <div> posted in <a href="http://electronichobbyist.tribe.net">Electronic Hobbyists</a> - 10 replies </div>

sillydiego 2006-03-23T03:13:17Z Tim http://electronichobbyist.tribe.net/thread/ca3b3125-9898-4adb-954c-177ceb753b37 2005-12-08T15:31:46Z 2004-04-15T11:42:15Z

<div>I'm installing track lighting that employs a 300 watt electronic transformer. Can I use a regular old dimmer with this, or do I need something special? If I use a regular old dimmer, will it in any way damage the xformer? <br/>Thanks.</div> <div> posted in <a href="http://electronichobbyist.tribe.net">Electronic Hobbyists</a> - 7 replies </div>

Tim 2004-04-15T11:42:15Z leerod http://electronichobbyist.tribe.net/thread/7de0a669-69cc-471d-a67a-0ec567366de5 2005-11-29T02:33:10Z 2005-11-28T04:58:36Z

<div>Hi all I'm a newb and I wanted to say hi and ask a question. <br/> <br/>Anyone work wioth gyroscopes much? <br/> <br/>I am working on a segway with balls, hopefull freeway speeds soon. <br/> <br/>I am trying to learn more about this? <br/> <br/>Anywhere I can look?</div> <div> posted in <a href="http://electronichobbyist.tribe.net">Electronic Hobbyists</a> - 2 replies </div>

leerod 2005-11-28T04:58:36Z oneflirter http://electronichobbyist.tribe.net/thread/b49a4e95-8736-4710-94cd-90714534203f 2005-04-07T19:17:46Z 2005-04-06T18:01:36Z

<div>I'm trying to make a shuttle for my company where a car (similar to a model train on a track) will go from one area to the next and stop off to pick up whatever someone puts on it and take off whatever is on there that they need. <br/> <br/>My problem is that I can make the thing go ... I just can't make it stop without "hitting a brick wall". Does anyone know how to make this so that it will go x number of feet and stop or go at top speed until it gets to a certain point before starting to slow to a smooth stop? I appreciate it.</div> <div> posted in <a href="http://electronichobbyist.tribe.net">Electronic Hobbyists</a> - 5 replies </div>

oneflirter 2005-04-06T18:01:36Z brainlight http://electronichobbyist.tribe.net/thread/f040d92e-1449-426d-90d7-074e100e28e3 2005-04-07T09:21:48Z 2005-04-05T20:36:17Z

<div>Kinda dead in here. <br/>Anyone care to share what they're doing? <br/> <br/>Me, last thing I did was to get a hobby servo working in a test configuration with a 555 timer. <br/> <br/>I have a bunch of strobe-control ideas, and other "smart lighting" things I'd like to try....</div> <div> posted in <a href="http://electronichobbyist.tribe.net">Electronic Hobbyists</a> - 4 replies </div>

brainlight 2005-04-05T20:36:17Z the rev http://electronichobbyist.tribe.net/thread/1d5c426a-17f2-469c-b643-a4ecc93a4345 2004-03-29T05:04:06Z 2004-03-29T05:04:06Z

<div>Has anyone any ideas on fixing a Video Disc Player? Problem is a recurring loop while playing. After 10-15 seconds, there is a slight phiszzt and the scene starts over. This happens on any disc, in any chapter. Player is a Pioneer cld s104 and has no rs232 port.</div> <div> posted in <a href="http://electronichobbyist.tribe.net">Electronic Hobbyists</a> - 0 replies </div>

the rev 2004-03-29T05:04:06Z