Need help with electronics

EB · Post by EB » Mon Jul 14, 2008 11:19 am

Hi guys,

I'm working on a FAMILY FEUD-style setup (what's more American Dream than being on a game show?) which includes a "face-off" podium where contestants buzz in against each other.

To make this happen, I've ordered (and since built) a buzzer system which will do exactly as I've described above. Here's the link to the kit:

http://www.vellemanusa.com/us/enu/produ ... ?id=351167

And, specifically, to the schematic of the device itself:

http://www.vellemanusa.com/downloads/0/manual_mk133.pdf

My question is this: I'd like to run more juice through the board so that when a contestant buzzes in, their side of the face off podium (to be built) would light up in traditional gameshow fashion as opposed to the tiny, enemic single LED that lights up with the kit.

The board lists the max power settings at 9V, 50mA but I'm wondering if I could replace some resistors (here's where my electronics knowledge ends) or what-not and send more juice through.

Or am I stuck with the board's limitations? (Or is there a work-around that I'm not thinking of...?)

Help!

Thanks,

EB

gyre · Post by **gyre** » Mon Jul 14, 2008 12:10 pm

You will need to step up the power handling somehow.
The best relay you can find in that power range to drive a bigger relay that can handle what you want, is one approach.
You might use a photorelay that is activated by a light source.
How much brightness or power do you want?
I ran into a similar issue building a digital stained glass clock.

EB · Post by EB » Mon Jul 14, 2008 1:08 pm

gyre wrote:You will need to step up the power handling somehow.
The best relay you can find in that power range to drive a bigger relay that can handle what you want, is one approach.
You might use a photorelay that is activated by a light source.
How much brightness or power do you want?
I ran into a similar issue building a digital stained glass clock.

Thanks, gyre.

re: smaller relay powering bigger one. Yes, I wonder if that's what it will take. Again, this is all sticking its foot past the frontiers of my electronics knowledge...

re: photorelay. As in, the tiny LED trips a bigger relay? I didn't think of that. Is that less efficient than a smaller electric relay?

re: brightness/power. 9V/500mA. Enough to power a yard of El Wire maybe... or maybe 10 or so LEDs. Imagine a gameshow setting where two people square off with their hands on a buzzer. The first player to hit the buzzer lights up his/her side of the podium. So, yeah, maybe a couple yards of EL wire and 20 or so LEDs.

gyre · Post by **gyre** » Mon Jul 14, 2008 1:32 pm

I haven't tried the optical relay, but it seems to have an advantage in simplicity and it's ability to step up power.
I don't recall them being cheap but neither are the hyper efficient relays.
I always have to order the hi effic relays.
I think I have a 12volt with resistance around 2600 ohms, maybe.
Gold contacts, of course.
There are many other possible approaches.

I think Luxeon LEDs are more efficient and they have the advantage of being very wide angle.
I have not been able to get adequate lumens rating on smaller LEDs to be sure.

There may be circuits available for LEDs and elwire designed to activate with a very low power signal.
This may work out for you if you want a complex flashing pattern.
Elwire appears to be more efficient than LEDs but I can't be sure.
I am convinced Lytec is the way to go for elwire.

cunfuzelled · Post by **cunfuzelled** » Mon Jul 14, 2008 10:21 pm

you need to find a solenoid that is activated by the voltage or a similar voltage to your indicator led on the circuit board. the output that it switches neads to be able to handle the load voltage and wattege of your lights on the front of your pannel. http://www.newark.com/ might have it otherwise there may be a product from http://www.watlow.com/ or look on ebay

watlow products are often offered on ebay for good prices.

fuze

Captain Goddammit · Post by **Captain Goddammit** » Mon Jul 14, 2008 10:59 pm

Especially if you're not super familiar with electronics, I'd say go with relays. The wiring is simple. Maybe a small one that the LED lamp circuit will trigger controlling a larger one, and you'll easily be able to run as much power as you like.
Another big reason:
You can get nice reliable well-sealed 12-volt relays that will stand up to playa conditions ultra cheap or free... at the wrecking yard. Mid '80s on up GM cars have a bunch of 'em, and they accept standard flat push-on wire connectors. I use them on my Land Yacht. Other cars should have them too.

gyre · Post by **gyre** » Mon Jul 14, 2008 11:09 pm

A lot of cars have relays that appear identical, but are not.
This can be a serious problem.
Other than that, I think it may be hard to find a low draw relay.
Some cars are using stepup relays and that would work if you can find them in the car.
You have to figure out the wiring pattern to them too.
Some of the auto relays are very cheap even new though.

I mostly use Potter and Brumfield for my better relays.
Carlton-Bates mostly for wholesale orders.
There are some good surplus dealers for audio and I have seen relays in their catalogs for 70 cents before.

EB · Post by EB » Wed Jul 16, 2008 9:32 am

Thanks for the input, guys.

So I'm looking for a low-draw relay that will put through at least 9v at 500mA? Is that correct?

gyre, you mentioned some catalogues that would have these; is it possible to get a link to one of them?

Thanks again,

EB

gyre · Post by **gyre** » Wed Jul 16, 2008 11:43 am

There are two ratings to keep in mind.
One is the power available from your circuit to power something.
The other is the power the relay can manage for you.
If it is wired separately the voltage can be different from the driving voltage on the coil.

You may want to to check to see who the local wholesalers are and you may have a distributor like Bluff City.
Nothing wrong with a car relay if you find what you need.

http://www.pandbrelays.com/
http://www.carlton-bates.com/Products.a ... tegoryID=2
http://www.digikey.com/

I think the one I used was a sensitive version of the R10.
You may have some difficulty finding 9 volt coils.
I think a high sensitivity 12 volt coil would work or you could use a resistor with a 6 volt.
P and B does not carry optical relays.

The high efficiency R10 may be efficient enough for your purpose.
There are even smaller reed relays which draw less power.
Don't be too conservative on your power need for the light you are going to use.
A elwire driver uses power too.
You probably won't need a second stepup relay though.

EB · Post by EB » Mon Jul 21, 2008 10:49 pm

Okay, so I've decided on going with the relay.

Now, question:

I want the power that normally goes into the little LED (see original post) to trip the relay. That little LED is powered by a 9v battery.

I want the relay to then free enough power to light up about 10 white LEDs.

What specific ratings on the relay(s) should I ask for?

Thanks again, guys

gyre · Post by **gyre** » Tue Jul 22, 2008 2:29 am

Are you certain the LED is getting 9 volts?
Besides efficiency, you don't want to overload your circuit.

Once you are sure of your voltage, you need to know your load through the relay contacts.
In most relays, it can be a different voltage.
Standard for LEDs is 20 milliamps, though there are some exceptions now.
Voltage starts at 1.5 and goes as high as 7.5, I think.
You may have an LED with a resistor built into it or added to the circuit.
It may be to your advantage to bypass it.

If you are sure you will never need a heavier load on it, figure out the total load across the contacts and start with the smallest or most efficient relays and work up.
A reed relay may work.
Some are actually solid state.
I think the ones I use are R10s.
I can't remember the actual power now, but it is stunningly low and they will run 5-7 A on 2 contacts.
But you have to order the special coils for that low power use.
And lower resistance is always better on the contacts.
I was running extremely low power through mine but wanted the low resistance.

Some relays are harder to wire than others.
This may be a factor for you too.
Some must be soldered in.
Others can be plugged in.

Mister Jellyfish Mister · Post by **Mister Jellyfish Mister** » Tue Jul 22, 2008 7:47 am

Hi EB. Glad to know you've made such great progress! We've used similar relays to the ones discussed here for the U-Me and Zsu Zsu projects. Yours may need to have different ratings due to the voltage output you can measure at your existing LED's.

Try this:

Go to www.digikey.com and copy and paste this into the "search" box:

relay reed dip spst

Then choose the relays that match your voltage and current needs. I'd go with LED's instead of el wire for lighting as they are cheaper and designed to cast light on/in objects.

While you're there, pick up one of these to install them on:
http://search.digikey.com/scripts/DkSea ... e=3405K-ND

Good luck!

EB · Post by EB » Tue Jul 22, 2008 8:41 am

Right on!

Thanks, Jelly, Gyre, Capn, cunfuzzled...

I believe this is the last piece of the puzzle before I put this project to bed!

gyre · Post by **gyre** » Tue Jul 22, 2008 9:27 am

You may wish to use a different power supply for the LEDs powered by the relay.
You could use D cells to power the LEDs, for instance.
Just match voltage of the LEDs.

You would have to have a relay with separate wiring from the coil for this.
A SPST will do what you need.
I often use DPST = double pole and use both contacts together.

Have you measured voltage output to the LED in the kit?

EB · Post by EB » Thu Aug 07, 2008 3:34 pm

Wanted to say thanks for the help, guys. (Jelly, you're the bomb! Jelly Bomb! Run!)

I tried the relay but it didn't work and I've moved on to a more inelegant solution but a solution nonetheless. The contestants will hit the buttons which will light up LEDs on the main board (for their eyes only) they, in turn will decide which contestant buzzed in first and then they'll light up the "face-off" panel.

Definitely a recipe for disaster, cheating and possible graft. PERFECT!

Thanks again!

gyre · Post by **gyre** » Thu Aug 07, 2008 8:02 pm

How did you wire it in?
If you left out the LED, some circuits need a precise load to work.
Or the relay may be too much load.
Sounds like the other approach is interesting though.