Help with relay switch

Wireless & IoT
1

Hello all.

I recently purchased a pir motion sensor (http://www.sparkfun.com/commerce/produc … ts_id=8630), a rf link transmitter (http://www.sparkfun.com/commerce/produc … ts_id=8946) and a rf link receiver (http://www.sparkfun.com/commerce/produc … ts_id=8950). I’d like to connect the pir to the rf transmitter and send signals to the receiver which will be connected to an arduino 2009 board. As far as I understand (I’m new to arduino and electronics) I need a relay switch between the pir and the transmitter. The problem is that I do not know what type of relay to buy. Can someone help me , please ?

Thanks.

2

You’ll need a microcontroller between the PIR and the transmitter if I’m understanding your project correctly.

3

I was thinking about this : pir->microcontroller(or relay)->rf transmitter … rf receiver->arduino board.

The thing is I know very little about microcontrollers and I was asking if there is a way to make the pir send the signals via rf the easy way (without having to program a microcontroller)

Thanks.

4

You’ll need two Arduinos in order to make this happen.

PIR → Arduino 1 → RFLink Transmitter

RFLink Receiver → Arduino 2

The reason for this is that you need to have a 0-to-1 or 1-to-0 transition on the transmitter’s data pin at least once every 30 milliseconds (e.g. the minimum baud rate is 300 bps for serial communication).

5

It could be done with a NE555 on the TX side and a tone decoder on the RX side.

Or a smaller processor like a 12F series PIC or TinyAT.

6

Take a look at the Rentron website for wireless remote control projects. They have sample [schematics with easy-to-follow information.

In your application the PIR drives a microcontroller (e.g. arduino) or encoder, the MCU/encoder drives the wireless transmitter. The wireless receiver drives a microcontroller or encoder, the MCU/encoder drives a transistor, which in turns drives the relay.](Reviews of Software & Service Providers | SERP)

7

Thank you guys. It all clear for me now.