I could solve this with a relay, but don't want to use a relay.

[Jon Raylaw]

I am wishing to build a unique centerpiece for my sister's wedding, using a Velleman Kit (**broken link removed**) but instead of driving the on board LEDs I wish to drive a different kind of LED, which will be more visually appealing (Flexible LED Strips).

If I was to use a relay, I would put it in place of the LEDs (LD1-LD4), and use it to drive the other LEDs with their own power supply. I have not metered the circuit yet to see if there is enough current to trip a relay, but regardless I want this to be a silent thing, as a centerpiece, and I do not want it clicking all night long.

I am not an EE by trade, but am very skilled at electrocuting myself, I say it in jest, but it is mostly true.

Any assistance that can be rendered would be greatly appreciated, as my mother wants me to commit to a final design, without a proper prototype.

 

[Marks256]

If the reason you are avoiding relays is the noise, what about some solid state relays?

 

[Hayato]

A transistor would work fine, as well.

 

[jimmythefool]

How about using the Velleman MK107 running led kit, and put the 8 outputs straight into a ULN2803A, then you could connect 1 led strip(cathode end) onto each open collector output, with all the anodes to +V
(You may need a Led series resistor to drop off any excess voltage, I haven't seen the datasheet for the Leds)


Jim

 

[Jon Raylaw]

Thanks for all the good ideas. So far I am leaning towards a transistor, as it is the most cost effective I can find, as well as having the smallest form factor. As the centerpieces only need to be functional for ~6 hours, and need to be completely iscolated hence DC power, and small enough to fit in the bottom of a glass vase.

The SSRelay was very intriguing, but the only part in the form factor I liked was $27 a piece.

I have never worked directly with a transistor before, and will be making a stop off at the local radio shack before hacking apart the Velleman Kit I have at home. It will take some playing with.

If anyone can recommend a transistor or schematic I would be very appreciative.

 

[Jon Raylaw]

Oh yeah, we are looking to build 15-25 of these centerpieces, hence needing things to be cost affective. We will be building these by hand, or more honestly my mother and her boyfriend, will be building these things. And the K.I.S.S. Method will be most well received.

 

[jimmythefool]

Oops..I didn't look at the circuit properly...I just saw the Mic, and realised it was a sound to light kit..
How many Led strips are you using?

 

[Jon Raylaw]

We are planning 3 x 1.2" LED strips of various colors. per: Flexible LED Strips they are rated at 12V and 20mA.

 

[jimmythefool]

Have a look at the current draw, and power handling on that transistor, it may handle 60mA with such an intermittent duty cycle, and maybe tweak the circuit a lil if necessary to run from 12v instead of 9?

Jim