Circuit design for keyfob receiver's TTL outputs for current - Electronic Circuits Projects Diagrams Free

Guerrero · 12th April 2005, 01:20 PM

Hello to everyone. This seems like a knowledgable and friendly forum, so I thought I'd see if anyone would be kind enough to assist me.

I plan to get a kit including a 3-switch keyfob and this receiver (datasheet):

http://www.maplin.co.uk/Media/PDFs/N87BN.pdf

I want to be able to activate some special effects using the keyfob, and 3 buttons on the fob is perfect. I have two light effects to turn on and off which require latching outputs and one flash pot thing (pot with flash powder in it to give light and smoke when detonated) which only needs to be a momentary output.

There are two hurdles to overcome, and I hope to overcome both with the use of a separate, small, homemade PCB - the smaller the better, as the parts need to be hidden inside objects.

The first problem is that the outputs are low current TTL outputs, and since I need a bit of current for the effects (not much, they are battery operated) I need to have those outputs turn on circuitry capable of passing the current through.

Secondly problem is that the 3 outputs can only be set all latching or all momentary. So, I was thinking it'd be easiest to set them all momentary, and then have the second PCB incorporate circuitry to take each momentary pulse and have that cause a latching effect on whatever component is chosen to act as a higher current switch for the voltage going to the two effects which require latching outputs.

Sound feasible and easy to do? I have little knowledge of circuit design, so although I know what could be used to do all of this, I haven't the ability to create a schematic of it with the correct components to do the job nicely.

Does anyone fancy helping me with this please, if they have time to spare? I'd be happy to supply some pics of it when finished and working.

Many thanks!

Pommie · 12th April 2005, 01:45 PM

Are you a magician?

Mike.

Guerrero · 12th April 2005, 01:59 PM

Nope. It's for spooky effects for a ghostly convention which is going to take place.

Roff · 13th April 2005, 03:35 PM

What's the point in adding latches, when you already have latching capability? Configure the outputs as latching and use logic-level MOSFETs as your drivers.

Guerrero · 16th April 2005, 10:06 AM

Quote:

What's the point in adding latches, when you already have latching capability? Configure the outputs as latching and use logic-level MOSFETs as your drivers.

The outputs can either be all latching or all momentary. I need one momentary out of the three.

Roff · 17th April 2005, 03:17 AM

See the schematic below. If you don't need to reset the latch until power is cycled, you can eliminate the Reset and A1c and A1d, and instead connect the junction of R1 and C1 directly to the point labeled rst.
The RC network provides power-on reset.

FRIED · 18th April 2005, 02:11 AM

4013 dual F/F, each wired as divide by 2. Momentary inputs to clocks

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12th April 2005, 01:20 PM	(permalink)
Guerrero	Circuit design for keyfob receiver's TTL outputs for current Hello to everyone. This seems like a knowledgable and friendly forum, so I thought I'd see if anyone would be kind enough to assist me. I plan to get a kit including a 3-switch keyfob and this receiver (datasheet): http://www.maplin.co.uk/Media/PDFs/N87BN.pdf I want to be able to activate some special effects using the keyfob, and 3 buttons on the fob is perfect. I have two light effects to turn on and off which require latching outputs and one flash pot thing (pot with flash powder in it to give light and smoke when detonated) which only needs to be a momentary output. There are two hurdles to overcome, and I hope to overcome both with the use of a separate, small, homemade PCB - the smaller the better, as the parts need to be hidden inside objects. The first problem is that the outputs are low current TTL outputs, and since I need a bit of current for the effects (not much, they are battery operated) I need to have those outputs turn on circuitry capable of passing the current through. Secondly problem is that the 3 outputs can only be set all latching or all momentary. So, I was thinking it'd be easiest to set them all momentary, and then have the second PCB incorporate circuitry to take each momentary pulse and have that cause a latching effect on whatever component is chosen to act as a higher current switch for the voltage going to the two effects which require latching outputs. Sound feasible and easy to do? I have little knowledge of circuit design, so although I know what could be used to do all of this, I haven't the ability to create a schematic of it with the correct components to do the job nicely. Does anyone fancy helping me with this please, if they have time to spare? I'd be happy to supply some pics of it when finished and working. Many thanks!

12th April 2005, 01:45 PM	(permalink)
Pommie	Are you a magician? Mike.

12th April 2005, 01:59 PM	(permalink)
Guerrero	Nope. It's for spooky effects for a ghostly convention which is going to take place.

13th April 2005, 03:35 PM	(permalink)
Roff	What's the point in adding latches, when you already have latching capability? Configure the outputs as latching and use logic-level MOSFETs as your drivers.

18th April 2005, 02:11 AM	(permalink)
FRIED	4013 dual F/F, each wired as divide by 2. Momentary inputs to clocks