233 replies to this topic

[BrightStar]

Hello all
I've finally finished my new firing system for this season, im quite chuffed how it turned out

Very nice indeed ... (quite envious here...) You could probably unplug a module and quickly plug in another mid-show to give even more cues.

Out of interest, how much current do you use for the continuity test? See you went for Cat 5 cabling - do you have any resistance values for it? Are those the matches from HFM Pyro?

...and all done in time for the 5th... lucky you...

Edited by BrightStar, 24 October 2006 - 06:11 PM.

[ProfHawking]

The test uses 5mA, and the length of cat5 doesnt seem to affect it much at such low current.
The resistance of the system seems to be about 0.7 ohms each way over a 5m cable, or 1.6ohms each way, over a 15m cable.
So, tehcnically when fired on the 15m cable it should be able to deliver 3.75 amps, in reality even 1amp should be plenty to pop the ignitors.

The ignitors werent from hfm. Though the HFM ones seem to have nicer longer leads so i may visit them next time.

[Ritual33]

ProfHawking, I'd be very greatfull if you could supply me with some schematics etc for that design. I have an almost unlimited supply of electronics as I brought a lifetime collection from a guy that retired a while back. One thing I havnt sourced yet is a decent hobby box to house the firing system modules, any ideas?

Regards,
Drew

[hoarp001]

Hi, Im new to the forum but not to pyro or sfx.

This is my 8ch pyro system I build afew months ago. It uses one common and 8 channel terminals. I use the banana type that have the little screw in terminals, so you can poke the wire though the hole and screw the clamp down on it. At the other end i usualy use terminal blocks or just do it the cheap way and wrap the wires around the bare copper and tape over it....

Pyro Controller

[Ritual33]

Thanks for that hoarp001, will prob base mine from yours *yoink*

Regards,
Drew

[ProfHawking]

Sorry ritual, bit late with more info. I got the project boxes from maplin. The electrical parts from rapid. The cat5 connector blocks from screwfix.
I've made one for you of my firing box here: http://www.clintweb....wsyscircuit.gif
My system effectively that times 4. I'm not certain that the resistors were 8.2K, will check that.

And hello hoarp001,
nice looking system you have, but i must say i think a strange way to fire your channels.
Wouldn't you want to fire them one by one in order? in which case you would have to turn on one channel, press fire, turn it off and turn on the next one, press fire, etc etc. Also, your continuity test LEDs can only be used just before you want to fire the channel, meaning you don't get much pre-warning of a problem if you are not firing all channels at the same time.
I've never seen a system like that and i must say i cant see the reasoning. If you want to fire more than one item at the same time you could just wire their ignitors to the same output...



Also, im working on a low cost firing sequencer unit. The idea is that i can run it off one of the channels from my firing system. It will not use its own power supply hence be safer, will have ajustable timings, and will be daisy-chainable.
I will keep you guys posted if i crack it. I expect the parts to cost about £50

Edited by ProfHawking, 14 November 2006 - 07:16 PM.

[Ritual33]

*hugs ProfHawking*
Just what I wanted, this design is crisp
Hopefully it will give me a kick start in electronics that I've wanted for a while, hell maybe a PIC controlled firing system that can do cool patterns, cannon fire, random fire etc eventually.

Where did you source your boxes btw?

Regards,
Drew

[BrightStar]

Yes, welcome hoarp001 - nice work.

I do think you might have an error or two in the circuit diagram though. I can't see any way in which the LEDs could light at all. For example, close SW10 to apply power, and the only current path for the power indicator D9 is through one of the oppositely polarised channel LEDs... ie, they cannot conduct and will never illuminate???

ProfHawking's circuit is nice - there is a certain level of safety and reliability in keeping things logical and simple... having said that, my PIC based distributed firing system is coming together, hopefully in time for New Year 07...

Edited by BrightStar, 14 November 2006 - 07:27 PM.

[pyromaniac303]

my PIC based distributed firing system is coming together, hopefully in time for New Year 07...

What microcontroller are you using?

I am using a 16F627, a 24c515 512kb serial EEPROM to store the firing cues, and as many 4097 (8 output serial device) as I can get away with. In theory you could have one tiny PIC controlling up to 256 firing cues using this method. When I have finished I'l post the full college project so that everyone gets full details of construction etc. Likely to be around june next year though...

The other advantage of it is that I can just replace the EEPROM with firing cues, and there is no need to reprogram the PIC for the next show. If anyone has any experience with serial eeprom programming via windows XP based PC, it would be very much appreciated, as the only one I've seen runs in linux (on alany's site actually!). Have heard that it is difficult to access the parallel port on anything above win98, as windows XP blocks any access attempts. Here is the article on it: parallel port errors with a few solutions to the problem.

[BrightStar]

What microcontroller are you using?

I'm using the PIC16F877A to prototype, just because I had a few lying around. The plan is a bit different from yours - I'm using a laptop as a sequencer to fire the cues and monitor status & continuity. The laptop acts as the bus master, streaming commands over an RS485 serial bus to simple PIC based firing modules (up to 32 in theory), distributed around the display site. I hope to make the modules simple and cheap enough to be able to do away with conventional slats. This is probably less reliable than your method of having a dedicated hardware sequencer, but will be fine for me.

I haven't had any experience with serial eeprom programming via windows. I'm using an ICD 2 clone via USB for development. As you say, direct port access can be unpredictable with XP. If you have a fairly generic parallel port though, you could probably boot into a live version of Ubuntu or Knoppix without having to install them. Either that or find an old PC with Win 98 or DOS

[Ritual33]

*Drools*

[leosedf]

BrighStar
RS485 is similar to DMX, is it something like that?

Edited by leosedf, 15 November 2006 - 09:44 AM.

[phildunford]

DMX 512 is a digital lighting protocol, but it uses RS485 as it's transmission medium.

The advantages of RS485 are:

1) it's differential rather than single ended, so it's more immune from interferance.
2) It can go up to 4000 feet (rather than about 50 for RS232)
3) It can use up to 32 recievers AND transmitters, so if it's implimented in the software, devices can talk back to the control unit.

[leosedf]

Why do you need a device to talk back?
Maybe the igniter test?

[hoarp001]

And hello hoarp001,
nice looking system you have, but i must say i think a strange way to fire your channels.
Wouldn't you want to fire them one by one in order? in which case you would have to turn on one channel, press fire, turn it off and turn on the next one, press fire, etc etc. Also, your continuity test LEDs can only be used just before you want to fire the channel, meaning you don't get much pre-warning of a problem if you are not firing all channels at the same time.
I've never seen a system like that and i must say i cant see the reasoning. If you want to fire more than one item at the same time you could just wire their ignitors to the same output...

If you want to do that, you just hold the red button down and then flick the switches in order. Its a safety so you cant accidentaly drop ot or put something on top of it and set all the fireworks off....