Brian

Know you said it works fine with the analog desk. It could be something to do with the patch cable from the dimmer to the Showtec demux.

 

IIRC, the pinouts on the D25 are not intuitive.

My guess is that is a Chinese clone of a LM2591.

 

(I see 2591 not 7591)

...wheels would just get in the way and are thus an add-on by users rather than JBL....

 

 

They do indeed appear to be an option.

Books include...

 

Getting Started with Arduino, 2nd ed - Banzi

 

Programming Arduino, Getting Started with Sketches, 2nd ed - Monk

 

Practical Arduino - Oxer and Blemmings

 

Beginning Arduino Programming - Evans

You only have to look at what other items the seller has to gauge the level of support available in the event of a problem.

...I bought one with a VERY similar part number that fitted the size and description from a company called Steppers online.

 

That's likely to be your problem. Unless it's the identical part number from the same manufacturer then they are likely to be different. To get an accurate match you'd need to be comparing the torque/speed/current graphs to make sure they really are the same.

I remember some old LM mini confetti cannons that used a 16G threaded CO2 bulb, and had a little level or something to actuate.

 

The Le Maitre mechanism comes from aircraft life jackets. Pull the lever and the whole 16g of CO2 is instantly released. Probably not what you want if you want fine control.

 

I'm wondering if a sprayed whipped cream N2O unit might be more controllable?

 

 

[EDIT]

Chemical formula for Nitrous Oxide corrected.

Though many projectors can be used vertically and you might be making this harder than it needs to be.

 

^^^That.

 

Surely if you're having to concoct a lash-up to suspend a mirror above people's heads then you may as well just sort out something to run the projector vertically?

What sort of delay period are we looking at?

Not really what we do on here but...looks like you'll have to use the headphone socket. Which will likely kill the in-built speakers so as well as feeding the loop amplifier you'll needs to feed an external speaker(s) if you want people to hear the sound without using the loop.

I would check with Milos but mixing truss brands is usually not recommended. it will also void any load tables and require specific engineering.

 

Thanks. This application is purely decorative so I have no concerns about suspended loads.

I'm looking for a few bits of Milos M222 Trio to extend an existing rig and wondered what other system it is compatible with so that I can extend my search.

Instant feedback would work. Especially if that feedback was an email with an invoice for remedial repairs attached.

That's a good shout - it hadn't occurred to me that a small transformer would be an option. And they're cheap enough that I can buy a couple to experiment with.

 

As long as you aren't passing DC through the winding you'll be OK. If you are then, depending on the size and construction of the transformer, you run the risk of saturating the core which'll reduce your headroom and introduce distortion.

^^^That.

 

The audio is run unbalanced and so you need an earth connection at one point, and only at one point, somewhere in the system. And the usual place to do that is the power supply. Using a wall-wart with no proper earth connection is not recommended.

No.

Hippy, would the name be "Light Engineering"?

Sorry Brian, I seem to have hijacked your thread.

 

No Problem.

 

I'm considering buying one of these...

 

QA401 Audio Analyzer

My question is, how would you get Smpte timecode from a video source? Does the video have to be created with a 3rd audio channel or is there another way. Timecode has come from video right? Is there a way of getting timecode from a video with no audio channel dedicated to this?

 

Depends entirely on the video source. There is a system called VITC which records the timecode in the vertical blanking of the video image as a video signal. You can then use a VITC to LTC translator to get 'audio' timecode. But this requires that your video source will deal with VITC. Or you might be lucky that the source will generate it's own LTC with a fixed relationship to the video.

 

Another important factor is that I want to be able to run the video (and Timecode) from my own laptop to build the cue stack so I can play/rewind and mess about with it myself without having to get the video tech to do all that for me. Once the lighting cue stack has been built we can test and run the show from the video playback computer

 

For that you are going to need to add the timecode to the audio track.

 

Given the variety of video sources you are likely to come across I would stick with using 'audio' timecode (LTC). So it now comes down to how to get LTC onto your video file on your laptop. And then there is the complication of different frame rates and start times.

 

TBH, I would request a copy of the video file from whoever is originating it and ask for them to add the timecode to it. You don't need a stereo track to design to so ask for a mono mix of the audio on the left channel and timecode on the right. Like that you don;t need anything special on the laptop.

Re:picosope

 

The problem is the resolution of the ADC. The best ones are only 16 bits which limits the resolution of any measurements.

The problem I am finding with going the 'audio interface' route is that they all seem to have level controls which makes doing anything with absolute levels difficult.

^^^That.

 

Whatever you do will need to be thick enough to take screws. If it isn't you run the risk of snapping them off as they hit the concrete below. And that isn't good news for a stage floor.

THD and S/N testing is going to be important.

Is anyone using a PC and some sort of interface to test audio equipment? Note that I'm not asking about any testing that involves 'acoustics', just 'electronics'. So I'm looking at alternatives to things like Audio Precision or Lindos kit.

 

I've seen several bits of software online which use external USB 'sound cards' but everyone seems to use expensive 24-bit 192k units. I'm not looking for audiophile performance so 24 bits is over the top, 16 is probably a bit low. Does anyone do 20-bit units? Or are there any decent 24-bit units which are a more reasonable price?

 

I can buy secondhand 'proper' audio test sets for around £400 so I guess that would be my budget for a more modern software and hardware solution.

To be fair, some units have inexplicably separate IN / OUT wiring and headers that are then commoned back at the PCB. :-)

 

But that's the proper way to do it. If you common at the connectors, and then run a 'spur' to the PCB, you will increase the risk of reflections. Whether that makes any difference to the signal is a whole different discussion.