please look over my RF circuit

[NleahciM]

Hi - so I'm horrible with RF stuff. So I thought it'd be best to post my design before I send this bugger off to Olimex.

Anyways - here's the schematic:

It has a bunch of parts that I would expect much of anybody to be familiar with. I also just realized that I have the wrong transistor in there - I think I must have started this schematic before I was very comfortable with making my own parts. That should be a 2N4401. Either way - the pinout is the same.
This is the RLP-434A: **broken link removed**
Notice that I'm using the Holtek HT-12D (**broken link removed**) exactly as it is shown used in the RLP-434A datasheet.
The other part that I would not expect anybody to be familiar with is a really odd little bugger - the BPS 200-2-14-50:
It is essentially just a board mountable power supply.

I expect I don't need to explain too much what this board does - but I will just in case. It is designed to switch the relay between it's two positions when it receives a specific signal from the RLP-434A which sends the signal to the HT-12D which decodes it, sending a pulse to the latch, which will then switch, switching the relay.

Hopefully that made sense.

OK with all that out of the way, here's my board:

So - how does it look?

 

[zachtheterrible]

So - how does it look?

Well you won't be needing to worry about stray capacitances and inductances on this, as all of the RF stuff is on the RX module; although it is always a good idea to keep leads and traces short as possible.

 

[chiba]

I don't know what you are planning to switch with the relay, but HT-12's have another 3 data latches, why not use them? ie..Bell, whistle and self destruct

 

[NleahciM]

I don't know what you are planning to switch with the relay, but HT-12's have another 3 data latches, why not use them? ie..Bell, whistle and self destruct

I just realized - HT-12Ds have latched outputs - don't they? I wonder if the latch is even necessary... I feel like I protoboarded it and it was - but that was probabaly 6 months ago. I'll try that out tomorrow.

About the extra outputs - I've been thinking I might just run them to a pin header, just in case I ever need them...

 

[NleahciM]

So - how does it look?

Well you won't be needing to worry about stray capacitances and inductances on this, as all of the RF stuff is on the RX module; although it is always a good idea to keep leads and traces short as possible.

What about the ground plane? I put it on top - with the idea that the antenna would be on top as well. Is this a good idea?

Also - should I be connecting earth ground to DC ground?

 

[zachtheterrible]

Yeah, i don't think a ground plane would hurt. Im not sure how well it will help in the way of range. I have a 433mhz module and got @ least 200 meters with it without a ground plane.

Not sure what you mean by connecting earth to DC ground? I think they're the same thing.

I forgot to look, but do you have decoupling capacitors?

 

[NleahciM]

Yeah, i don't think a ground plane would hurt. Im not sure how well it will help in the way of range. I have a 433mhz module and got @ least 200 meters with it without a ground plane.

Not sure what you mean by connecting earth to DC ground? I think they're the same thing.

I forgot to look, but do you have decoupling capacitors?

No - I haven't added those in yet... Wasn't sure if I needed anything besides maybe a tanalum on the HT12D and the RLP-434A.

About earth and ground and whatnot - notice that the BPS module is a 5V DC supply with an AC input. What I'm wondering is if I should be connecting AC ground to DC ground, or if I should leave them seperate. I'm not very knowledgeable when it comes to AC stuff which is why I thought it'd be best if I asked.

 

[adamthole]

Everything looks correct to me, assuming you are using the BIAS thing correctly. I have made several circuits using the HT12D and the the Laipac Receiver, so I am familiar with those. BTW, did you make the HT12D and Laipac Receiver stuff in Eagle or was it in a stock library?

I used eagle for my board, but I just used a generic 18 pin DIP for the HT12D and pin headers for the RF receiver. If those aren't stock libraries, I would be interested in using them, if that's cool with you.

Here is my schem/board...if your interested. Notice mine is used to enable/disable a 555 timer that then powers a dc motor.

 

[NleahciM]

There's a Holtek library at cadsoft.de. The Laipac parts (along with the Bias part, and the relay) I all made myself in a custom library.