Cue Lights

[Andrew C]

. I've had a look at the wiki page and the schematic for the advanced system with flashing and acknowledge seems to be a broken link now.

 

Fixed now. I'd had a prune and sort out in the Photobucket albums and broken the link.

[cedd]

Hey everyone.

 

I did promise some drawings of my slightly more complicated cue light system. The fundamental principles are the same as the simple system linked above. The difference being it makes use of relay latches and momentary push switches. Doing this means it's possible to have groups so a toggle switch under the channel can add it to a master bus. You can have an infinite number of buses, each with its' own standby and go buttons (not shown, but you just ground the bus wire running across the page).

 

Apologies for that wire that vanishes off the left of the screen. It's actually there and runs down the left hand edge, but the auto crop feature in Visio has cropped it right up next to the line so it's hard to see.

 

The pinout on the 3 pin XLR is from memory of my system - use what you like! Just check your outstations are cabled the same.

 

I've built a trial 2 channel system from this version using modular drop in relays and it works fine, so I'm hoping it's pretty much correct.

 

Hope it's helpful. Feel free to add to the wiki. I'm hoping to persuade a friend who's got pcb etching abilities to make me up a few cards rather than my current mess of wires to individual relays that I'm using.

My new real system is actually different to this in that my local indicator lamps are actually replaced by relays. This means that they can switch between a dimmed lamp voltage and full voltage. This means the panel can be seen in the dark and as I use illuminated push buttons as the switch and also indicator it means you can always see the right button to press, but it lights up brighter when indicating standby or go.

 

Quite chuffed with it if I'm honest.

 

https://www.dropbox.com/s/6cf7st2f1v81r28/Cue%20Light.bmp?m

[boatman]

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https://www.dropbox.com/s/6cf7st2f1v81r28/Cue%20Light.bmp?m

 

I didn't see a "Cancel" button anywhere. You do need to be able to turn a channel off again. It could be as simple as a push-to-break momentary button in the +24V supply to the relays. A "Bus Cancel" will be a bit more complex, probably the simplest way to achieve that is an extra pole on the assignment switch and an extra relay, instead of the "Cancel" button, to interrupt the relay supply in each channel. The local cancel button would then need to drive that relay and the "Bus Cancel" line.

 

Hope that helps.

[cedd]

That's true yes. The standby auto-cancels once the go button is pressed, but in the event of accidentally pressing the wrong standby button there's no way of cancelling it apart from very quickly stabbing the go button and hoping nobody sees! One nice solution would be some kind of flip flop on the standby button so a second press cancels the standby, but I've tried to keep it all relay logic for simplicity, so maybe just a cancel button would do.

 

Bus cancel could indeed get tricky. I could do the trick you describe above on my own system as I actually use a relay to assign my channel to the bus. This is mainly because I got hold of a really neat looking 5 x 5 matrix of backlit push buttons from work, but they were all momentary, so there are latching relays everywhere in the thing! There's also a bus assign cancel button, which clears down the whole bus assignment. Sounds complicated but with a set of nicely backlit buttons that only light when an assignment is made, it actually looks quite neat.

[boatman]

Prompted by Cedd's system I have designed and prototyped an electronic cuelight system. It's a modular system with the channel board being based around a PIC12F615. It will provide bi-polar constant current outputs on two pins for reverse parallel LEDs as the signalling devices. The remote LEDs will be in series with the local LEDs so, as an aid to testing, the local LEDs will not light if the remote channel is disconnected.

 

Each channel will be able to connect to one (or more) of four busses for "Standby" and "Go" buttons and will have an independent local "Clear" button. Any channel board can be connected to all four busses if required and the busses are isolated so there will be no feedback to other channels.

 

I have put a project proposal on the Elektor Labs site so, if you are interested, please go and vote for it and help promote it to "In Progress" status.

 

If the project doesn't get accepted by Elektor, it will eventually appear on my own site.

[cedd]

Great stuff!

I'll vote for it when I'm on my home computer that doesn't think every website under the sun is inappropriate!

 

I'm approaching a friend who has a side line in PCB manufacture with the drawings for my most recent system. All my current systems have involved plug in relays which are a bit expensive. Hoping to use cheaper reed relays and he says he's going to have a look at the logic to see if it can be done with IC's instead.

 

I foresee a little board with contacts on the left and right side carrying the power supply and buses through. These may even be connectors so the boards can just be plugged side by side without any soldering. Then at the top, 3 contacts going to the XLR, and at the bottom the contacts to the front panel, including go, standby, bus assign, bus assign cancel and the front panel LED's. I'm also hoping to include a 2 pole relay for every indicator, with a seperate lamp drive power supply bus, so if using illuminated push switches you can have them dimly lit, which will then toggle to full brightness when they're indicating. Might even include a dimmer control with PWM.

 

I'm finding it really hard to find decent 24v split rail supplies, so I'm going to ask him to build an inverter circuit. Might even stick one on each board so they only need a +24v and 0v supply each to work.

 

No idea on pricing yet, but I'm exploring the options of either getting him to drill and populate them, or supplying them just as PCB's with a parts list for somewhere like CPC or Farnell.

 

 

If it becomes a viable option then we might consider producing a batch. I really like the idea of a modular system. Outstations are so simple that they don't need a pcb.

 

Is there a set convention for pinout? Ground on pin 1 I'm guessing. I'd maybe go with +/-24v on pin 2 and signal on pin 3.

[timd]

If you want properly done PCBs, look at itead. I've had a few batches from them and they've been fantastic. Some people have had problems with pushing the tolerances too far.

[boatman]

Great stuff!

I'll vote for it when I'm on my home computer that doesn't think every website under the sun is inappropriate!

 

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Thanks.

 

I've used a 16-pin IDC connector mounted on the underside of the board for the bus as it wont interfere with the top-side connections to the switches. The PCB is already laid out but not manufactured. The code for the PIC is almost done. I've got one channel built on a breadboard and I'll probably throw a couple together on stripboard for an evaluation system.

 

I chose bi-polar constant current sources as there's no need for twin rails and the supply voltage can be anything from 9V to 40V from a wall-wart. The most expensive part of each channel will be the PCB. The PIC costs 75P, 25 resistors @ .25P, 11 BC547 @ 4p, 2 BC557 @ 14P a few caps and a 78L05 @ 50P. Apart from the PCB, the total BOM is less than £5! The PCB is only 4" X 2" so shouldn't be too expensive.

 

If you need a PCB laid out send me a PM and I'll be happy to do that for you.

 

If you want properly done PCBs, look at itead. I've had a few batches from them and they've been fantastic. Some people have had problems with pushing the tolerances too far.

 

Thanks, excellent prices.

[Brian]

...so shouldn't be too expensive.

To give people an idea...about £5 each in a batch of 20.

[cedd]

So is your PIC sorting out the flashing standby as well? That makes life a lot easier if so. My system relied on a flashing rail driven from an external flash group. I guess the only down side would be that if you put several channels in to standby on the master station, their flashes wouldn't be in sync. I have a system that uses flashing indicators at work and it gets very difficult to read when they're all flashing and out of sync.

 

Do you think there's a chance of your system allowing the indicators to be dimly lit on the master station when a channel's not in use? Would allow you to use illuminated push buttons without the need to illuminate the panel. I'd planned on every button having a reed relay on the PCB so it toggled between dimly lit when not in use, and full brightness when selected. Even the bus assign and the bus clear. Makes for a lot of relays on the board, but I'm a big fan of relay logic! It would maybe work if the local LED was replaced with a small relay. Bus assign can be done within the push switch as long as it's latching, double pole.

 

Would you be interested in producing and selling them? If so then I may not bother pushing mine in to production.

[boatman]

So is your PIC sorting out the flashing standby as well? That makes life a lot easier if so. My system relied on a flashing rail driven from an external flash group. I guess the only down side would be that if you put several channels in to standby on the master station, their flashes wouldn't be in sync. I have a system that uses flashing indicators at work and it gets very difficult to read when they're all flashing and out of sync.

 

Yes, the PIC does everything. I must admit I hadn't thought about out of sync flashing, which I agree could be quite disturbing. There is one spare input on the 8-pin PIC and I've used it as an analogue input to determine how long the "Go" LEDS stay on after the "Go" button is released. If that's not needed I could dedicate that pin as a sync pulse input and have a hardware sync generator on one board.

 

Do you think there's a chance of your system allowing the indicators to be dimly lit on the master station when a channel's not in use? Would allow you to use illuminated push buttons without the need to illuminate the panel. I'd planned on every button having a reed relay on the PCB so it toggled between dimly lit when not in use, and full brightness when selected. Even the bus assign and the bus clear. Makes for a lot of relays on the board, but I'm a big fan of relay logic! It would maybe work if the local LED was replaced with a small relay. Bus assign can be done within the push switch as long as it's latching, double pole.

 

That might not work as it's currently designed. The remote and local LEDs are all in series and, because it's constant current, there can be as many as the available power supply will drive. I have also allowed for the remote "Acknowledge" button to act as an alert signal back to the console. If it is pushed when the channel is inactive or on steady red the LEDs will flash alternately at a fast rate to attract attention. The channel will drop back to its previous state as soon as the "Acknowledge" button is released. I guess that with a bit of diode logic and a couple of extra transistors I could probably make it work your way.

 

Would you be interested in producing and selling them? If so then I may not bother pushing mine in to production.

 

With PCBs at £5 + a BOM of £5 I would probably have to sell them at £15-£20 to be worth my while. If that sounds OK then yes I'm happy to make them available.

 

E2A: Thanks to all those who visited the Elektor site. After only 42 views I already have five stars! I don't know exactly what that means yet but I expect I'll find out in a day or two.

 

Edited to add even more: Chris, I've just looked at your schematic again and we have started from slightly different points. Your system has a set of buttons per channel which can be assigned to control other channels as well. My system has a channel which can be controlled from any (or all) of four sets of buttons. A typical configuration which I envisage would be channels 1,2 & 3 being controlled by button set 1 and channels 4,5 & 6 being controlled by button set 2. However channels 2, 4 & 6 could also be controlled by button set 3 without interfering with those channels only assigned to the other button sets. I think that probably means it's not possible to make the buttons light up dimly when nothing is on and brightly when the channel is active. I'll need to draw a panel layout so you see what I mean.

[cedd]

Just an update on my progress with this one. I was talking to a friend whose hobby is electronics design. He's really interested and has some ideas on how this system might come together. I think I might continue development of my system alongside what Boatman is doing, as we've approached things slightly differently when it comes to the bus assign functions, and I think both methods probably have a place out there.

 

We're making a few tweaks to the original design, starting with the removal of all the relays from the system! It'll all be solid state, MOSFET based electronics. We're designing it to be modular, so you just get as many pcb's as you need and stack them, with pcb connectors joining them together. There will be a separate utility pcb which will go anywhere in the chain and be the point of power injection, will hold the flasher circuit, and also a dimmer for the panel lamps.

We're mounting DC-DC converters on each pcb, so there's no need to have a -24V supply rail. This means the system is completely scalable, just keep adding channel pcb's and then get a +24v supply of the correct size to drive it all. Finding -24V supplies of a suitable size was proving difficult.

The local lamp outputs from each channel will be dimmed when not in use, so each button has a backlight. This allows you to use an illuminated push button both as the switch and the indicator. They'll light at full brightness when activated. For people using separate toggle switches and lamps you'll just cut a pin and the lamps will no longer light when not activated.

 

All front panel functions will be controlled by a single wire per function, plus a common ground. This keeps the number of wires to the front panel down and I'm hoping to use a multiway "D" connector and cable so it's possible for the control panel to be easily desk mounted, with the power supply and control box remote, so it cuts down on cable on the desktop (in my own system that is).

 

I'm also going to use an illuminated acknowledge switch at the outstation so it's easier to find in the dark. There's no permanent 24v supply to the outstations, so I'm planning on having a capacitor, resistor and diode inside it so as soon as the flashing 24v supply arrives, it charges up and lights the switch for a while afterwards, before fading out. Should be long enough to do an acknowledge.

 

It'll be a couple of weeks before he can get started as he's got another project on, but now I know he's interested I may find myself passing him the drawings for Comclone as well - I never got a system working, but I'm pretty sure he will! He's also got his own bubble etch tank which is always handy!

[boatman]

The software is all done and dusted, the PCB layout is finished and 10 boards are on order from iTead. There are a couple of minor changes. I did away with the analogue programming of the on time for the green "Go" LED after the "Go" button is released and changed it to use a "Clear" button. I also added a 3-pin PCB mounted XLR socket, so the channel module is ready to bolt onto a back panel directly. As the LED drive is constant current the power supply can be anything from 9VDC to 40VDC. Obviously the lower the power supply voltage the more energy efficient the system is, but with higher voltages more LEDs can be driven in series.

 

The prototype uses dual-colour (red & green) LEDs but individual back-to-back LEDs will also work. Red & green LEDs can have different values of current supplied for different brightnesses.

 

The software also allows for reverse communication. If the remote acknowledge button is pressed when there is either no LED lit or the red LED is steady, the red and green LEDs will flash alternately at a fast rate to attract attention. The channel will go back to the state it was previously in as soon as the remote button is released.

 

I'll let you know when boards have been built and tested.

 

Edit to add: The finished PCB is less than 2" by 4" to get under the iTead price breaks.

[boatman]

Just had an email from ITead to say that the channel boards have been dispatched. I have also ordered some slave boards which are small enough to fit four on a panel inside the 5cm by 10cm ITead limit. They are ordered and should be here by the time I have assembled and tested a couple of channel boards.

 

Click on the thumbnails to see larger pics.

 

http://www.mydesk.myzen.co.uk/_Useful/CuelightMasterSmall.jpg

 

http://www.mydesk.myzen.co.uk/_Useful/CuelightSlaveSmall.jpg

[dbuckley]

Nice!