Pic + RF Module or RFPIC

[koossa]

Good day

I want to do RF communication..
If I compare a Pic + separate RF Module with a RFPIC, it seems that the rfPic is cheaper and more reliable. Is this correct?

If so, why do so few people use it?

[mackrackit]

Not so sure they are cheaper.
The receiver RFPIC still needs a "regular" PIC plus many other external parts.
The transmitter is based on a 12F675. the 675 is a nice part but has limits.

The RF modules like the ones Bruce sells are pretty much plug and play and can be used with any PIC.

More reliable???
Who knows???

[koossa]

Dave, thank you very much for your reply!!

What I want is a cheap and reliable way to transmit data.
According to the microchip link (http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en010384) the rfPIC12F675K cost USD2.40

I actually want the most cost effective way to Transmit RF data over about 15meters.
I did play around with RF in the past and I struggled so much that I just never touch it again, so I want a solution that would not take me months to get working.

[mackrackit]

That seems cheap, but the you need the receiver also. rfRXD0420/0920 $2.89 from MicroChip. LQFP package :eek: If you are doing a production run they would be great.

But if it is a one or two thing....

The cheapest/ease of use I know of is these
http://www.rentron.com/remote_control/TWS-434.htm
http://www.rentron.com/remote_control/RWS-434.htm
All the need is an antenna and a PIC.
I tested some and had no trouble at a half mile line of sight.

Just my opinion.

[koossa]

Dave, thank you!

My problem is, that my customers will have for example 10-500 transmitters and 1 receiver and I want to go in production with it, so $1 would make a huge difference

I just want to transmit a 15 digit ID, one at a time.
Do you think I would easily get the Microchip rfPIC12F675K running?

[mackrackit]

I see. Many units...

I have not used the parts individually. Helped with a dev board setup. Seems pretty straight forward.

Here is a sample code from Bruce
http://www.picbasic.co.uk/forum/showthread.php?t=7241&p=44830#post44830

Sending the data should be easy enough. You will need a checksum or some other error checking.
The basic code could be


SEROUT2 PORTC.6, 16780, [ STR DATAOUT\16, $d, $a]

[koossa]

Thank you very much Dave!!

[mackrackit]

One last thing if you have not seen it yet.
The basic hardware for the receiver side of Microchip's rf stuff.
http://ww1.microchip.com/downloads/en/AppNotes/tb070a.pdf

[Ioannis]

If you insist on using an rfPIC thats fine. But for the receiver, since it is one piece, why not use the module proposed?

As David said is plug and play.

Note that you can use Serial commands for transmiting the ID but you have to use some NRZ enoding. Like Bi-phase or Manchester. It has to do with he receiver itself.

Ioannis

[koossa]

Hi Ioannis

I would love to use the Module from rentron, but the only thing is the price of the Transmitter because we would have maybe a couple of hundred transmitters per customer and only 1 receiver.
So the receiver I'm willing to pay more.

Will I be able to use the microchip transmitter pic with the rentron receiver?

[Ioannis]

As long as you are on the same frequency and usin the same modulation (ASK, FSK, FM etc) you are OK to use whatever you want.

Keep in mind that RF is not a piece of cake. You have to make tuning circuits, adjustments, have Spectrum analyzers to check for harmonics etc.

Using a ready made module all these are done for you and as a plus you get the certification. Can you get a certification for your product? I can assure you that it is very costly.

Talk to Bruce, he may find you a good solution from all aspects.

Ioannis

[koossa]

Thank you Ioannis, now I understand better.

[dhouston]

Using a ready made module all these are done for you and as a plus you get the certification. Can you get a certification for your product? I can assure you that it is very costly.If this is for N. America, the units Bruce sells are not pre-certified (unless FCC regs have changed recently). Depending on the design details (e.g. superhet or suprerregen receiver), testing of the complete circuitry (including antennas), must be done in FCC approved labs. This can run to several thousands of dollars for both transmitter and receiver so initial cost of the components is of minor importance unless your market is for millions of units. If your market is large, you can buy similar transmitters and receivers from China for about $1 each. And you can get custom features for even modest sized quantities without raising the cost that much.

If your market is of modest size, there is an FCC exception for home-built devices and units like those Bruce sells lend themselves to DIY designs (and are also likely to be an advantage where certification testing is required). But the definition of home-built is an imprecise gray area - even supplying a schematic can disqualify a design in some cases. You really need to know the regulations in your country before jumping in. In the USA, see the FCC Part 15 regulations.