My First DRSSTC / Projects / Forums

Forums

4hv.org :: Forums :: Projects

« Previous topic | Next topic »

My First DRSSTC

1 2 next

Move Thread

LAN_403

TheBoozer

Tue May 19 2009, 10:19PM

Registered Member #1535 Joined: Wed Jun 11 2008, 11:37PM
Location: Northeastern Pennsylvania - USA
Posts: 117

It seems to work very well when the interrupter isn't getting interference. Here's a clip of it putting out around 3 feet:

I've reached a stumbling block. At 120vac input and above the interrupter gets finicky. I would really appreciate some advice.

It's assembled in an aluminum project box. I used a shielded cat5 cable. The shield is connected inside the box to a side wall. The cable is 8.5 feet long. Am I too close? I attached the coil end of the shield to rf ground and the interrupter only puts out one rf cycle. Maybe it's resetting the timers? (My coils rf ground is an 8 foot ground rod pounded into the floor of my dirt basement.) I attached the shield to a radiator in the house whose pipe eventually leads to ground and it helps only a little. If I lay the interrupter on the carpet and push the button, I only get one rf cycle. If I hold the box in my hand and push the button it works better. Higher input voltages make the problem worse, so I'm stuck now. It seems to reset the timers at higher power levels. At 80vac in I could crank the duty cycle to 250ÂµS. At 120vac in I can only get about 200ÂµS. At 190vac in I get about 150ÂµS.

It's not the OCD circuit kicking in. Like I mentioned, it's moody. I also ground it to my drill press this weekend and I got four footers. That day I could crank the duty cycle up until the OCD light lit, but lately it's giving me grief.

Also, if the arc hits any target, grounded or not, the interrupter halts immediately until I release the button and press it again. It's the latest board posted on Steve Ward's site.

I can't believe I made it this far just to get stuck at this point. If I overcome this hurdle, then it's well worth documenting. There are some stats listed on the YouTube page. I wouldn't normally ask for help, but I'm perplexed. I believe everything is proper. My searches have been in vain. Argh!!!

My biggest bummer now is my landlord is back from vacation. He lives on the other side of the wall. He liked my previous coils, but this thing is LOUD. I won't get much troubleshooting time now.....

Thanks,
Rich

Finn Hammer

Wed May 20 2009, 05:32AM

Registered Member #205 Joined: Sat Feb 18 2006, 11:59AM
Location: SkÃ¸rping, Denmark
Posts: 741

Rich,

Nice coil.
After going trough the griefs of receiving shocks from my controller, I shifted to fiber optic communication for my coils. It is very easy to work with.

The transmitter is simply a LED, and the detector has schmitt trigger input, and either open collector or totem pole output. Chose your flavour.
The transmitter only needs, say 10-20mA, so can be driven right off the 555, and the receiver can be powered by up to 16V.

Check them out, you won't go back once you've tried them. Cheap too!

Part nos. Digikey FB123-ND (TTL) , FB124-ND (OC) and FB128-ND (transmitter)

Fiber is standard 1000Âµ poly fiber, and I was unable to find any (exept 500m rolls) in digikey, but theyÂ´ve got it.

EDIT: seems like they cut 10Meters for you (value added item) : A1700-10-ND

Good luck, Finn Hammer

LithiumLord

Wed May 20 2009, 12:34PM

Registered Member #1739 Joined: Fri Oct 03 2008, 10:05AM
Location: Moscow, Russia
Posts: 261

Hmm, no idea why, but I had alike effects even on lower power levels. A schematic would be nice to see, though I guess we had the same issue. Myself I solved it by both making a heavy ground on the controller cable (I use 4-wire shielded cable with shield and one of the wires connected together as a ground wire and two other wires as 12-18v unregulated supply line that is termnated with caps on both sides, leaving one wire as a signal one) and making the interruptor a built-in trggered one, so that the cycles are timed by a device placed on the driver board that is triggered externally. You can take a look at my project thread for some more clear info.

TheBoozer

Thu May 21 2009, 12:38AM

Registered Member #1535 Joined: Wed Jun 11 2008, 11:37PM
Location: Northeastern Pennsylvania - USA
Posts: 117

Thanks for all those Digikey part numbers Finn. Fiber optic was on the agenda because I will migrate to an Atmel AVR controller next. I want to hear music. :) Playing with microcontrollers is more my speed anyhow. Thank you...

I'll start with that conversion and see what it does for me. EMI protection is greek to me. :(

TheBoozer

Sat Jun 27 2009, 12:29PM

Registered Member #1535 Joined: Wed Jun 11 2008, 11:37PM
Location: Northeastern Pennsylvania - USA
Posts: 117

It took weeks for DigiKey to restock the fiber optic transmitters. I was impatient and couldn't just sit on my hands. I fried several 555 timers in my vain attempts at shielding. Unfortunately, the timers output shorted and stayed high when they died. This took out a brick everytime.

I went with the TTL receivers and the parts finally arrived Thursday. I finally got to try this on Saturday morning. Wow. No more interference. I can even maintain long arcs to a grounded target. Thanks Finn!!!:-)

At least with that headache out of the way, I can move on to microcontoller based remotes. I have so little time due to work and a long commute. A little nudge in the right direction sure saves me a lot of time. Thanks again Finn...

Rich

Finn Hammer

Sat Jun 27 2009, 06:44PM

Registered Member #205 Joined: Sat Feb 18 2006, 11:59AM
Location: SkÃ¸rping, Denmark
Posts: 741

You are welcome!
I am only very happy that you tried it.
I still remember the thrill of _not_ having a tingeling controller box in my hand, when sparks were issued.
And the relief it was to no longer have to think about what would happen if a streamer struck the cord.

Optic fiber rules!

Cheers, Finn Hammer

Andri

Mon Jun 29 2009, 10:30AM

Registered Member #1533 Joined: Wed Jun 11 2008, 02:13PM
Location: ReykjavÃk, Iceland
Posts: 46

These are some impressive sparks.

Have you guys tried putting a common mode choke on a coax? What I'm suggesting here is putting a few windings on the coax (perhaps even through a ferrite core) close to the controller.

TheBoozer

Mon Jun 29 2009, 09:48PM

Registered Member #1535 Joined: Wed Jun 11 2008, 11:37PM
Location: Northeastern Pennsylvania - USA
Posts: 117

I tried several different chokes. Tried looping through ferrite toroids, snap together chokes. Nothing appeared to have any influence. Maybe proper placement of caps somewhere would have helped? The cost of converting to fiber was ballpark about $35 USD. Considering the time and cost of the rest of the system, this was well worth it.

Of course in my world nothing ever goes according to plan. I added the fiber Friday night and it didn't work. I went to bed frustrated. Tired after a long day of work. Slept on it. Woke up realizing that the 555 timers I stocked up on have very little output current capability. Added a small FET Saturday morning and shortly after was ducking for cover.

All my future coils will be Fiber only.

magnetomotive

Wed Jul 15 2009, 06:32AM

Registered Member #267 Joined: Mon Feb 27 2006, 09:44PM
Location:
Posts: 46

That is a very nice coil! I'm glad I found this thread. I will definitely go with fiber when I design my DRSSTC.

TheBoozer

Sat Jul 25 2009, 07:24PM

Registered Member #1535 Joined: Wed Jun 11 2008, 11:37PM
Location: Northeastern Pennsylvania - USA
Posts: 117

One thing I didn't like about the fiber was how thin and fragile it looked. I went to the drug store and bought a 25 foot piece of oxygen tubing for respirators. I easily fished it through there and now I have a much more durable cable... Just thought I'd mention this...

My coil still needs major work, but it is functional. Wanting to do something different this week, I chose to design an Atmel microcontroller based interrupter. That went well, so I decided to try my hand at converting midi files. I have a lot to learn about notes and tempo yet, but it worked well enough on the first attempt to inspire me to post a YouTube video...

Here's my 1st attempt at Popcorn:

My music conversion skills need work, but it made nice arcs with a catchy beat.

Rich

1 2 next

Moderator(s): Chris Russell, Noelle, Alex, Tesladownunder, Dave Marshall, Dave Billington, Bjørn, Steve Conner, Wolfram, Kizmo, Mads Barnkob