You are planning to use Arduino in your project but you need some kind of remote control functionality. A standalone Arduino won’t provide what you need but this DIY shield may be a good solution for you. It includes a 433.92Mhz RF receiver which lets you send commands to Arduino wirelessly and four SPDT relays which can be used for switching purposes.
Each relay is capable of switching up to 10A @ 250VAC so they can be used to control mains powered devices. There are four LEDS indicating the status of the relays. The terminal blocks on the shield lets you easily connect the devices you will control.
The RF receiver is a module that can be found in the market easily. It is directly soldered to the shield and runs at 4800bps. The board has an antenna input which lets you solder your custom antenna to increase the wireless range.
The schematic of the project is drawn in SoloCapture, the schematic editor of SoloPCB Designer. SoloCapture makes the schematic drawing process very easy and fast. You can download SoloPCB Designer tools at Solo-Labs.com for FREE.
You can download the SoloPCB Designer design files of the project by using the link below.
Download DIY Arduino RF Receiver and Relay Shield SoloPCB Designer Files
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Please check out this video to see how to import the project libraries, open and synchronize the schematic and PCB files.
Since this is an Arduino shield, there should be connections to the expansion headers of Arduino. J5 to J8 connectors are used for this purpose. They are 2.54mm pitch, 15 mm male headers. The power and the signal lines are carried to the shield over these connectors.
There are four SPDT (Single Pole Double Throw) relays and their drivers on the board. The relays are from Finder’s 40.51 series, have 12V coils and 10A rated poles. The current passing through the relay coils are controlled by using the BC817 general purpose NPN transistors. A logic high on the transistor base triggers the relay. A logic low turns off the transistor and cuts-off the coil current.To prevent the harm of the back EMF during the turn-off action, 1N4007 diodes are connected in the reverse direction of the coil current. There are also LEDs connected in parallel to the relay coils with their current limiting resistors to indicate the relay status.
12V level required to drive the relay coils is applied to the the power input connector of Arduino from a wall adapter and carried to the shield over the Vin pin located on the expansion headers.
Each relay has a 1×3 screw terminal block connected to its poles. This lets the user easily connect the device which will be controlled.
The RF module on the shield is an off-the-shelf product that you can buy from Sparkfun, RWS-371. It works at 433.92MHz nominal frequency and rated at 4800bps. Any transmitter works at this frequency can send data to the module. The transmitter can be a remote controller, a sensor or any other custom circuitry. The data received by the module will be read by Arduino. There are also Arduino libraries for the module provided on the product page.
The PCB of the project is designed in SoloPCB Designer. SoloPCB Designer is a pack of powerful tools consisting of schematic capture, PCB layout, and integrated autorouting. You can download SoloPCB Designer at Solo-Labs.com for FREE and start using immediately.
The shield outline dimensions should be similar to Arduino. The male headers should be properly positioned over the Arduino expansion headers. The high profile components should be positioned at the top layer. Since the relays are rated at 10, the connections between the relays and the terminal blocks should be thick enough to be able to carry this current.
|1||10uF 25V X7R 1206 Ceramic Capacitor||C1|
|4||1K8 5% 0805 Resistor||R1 R2 R3 R14|
|8||2K 5% 0805 Resistor||R4 R5 R6 R7 R8 R9 R10 R11 R13|
|1||0R 5% 0805 Resistor||R15|
|4||1N4007 SMD Diode||D1 D2 D3 D4|
|4||LED Green SMD 0805||D6 D7 D8 D9|
|1||LED Red SMD 0805||D5|
|4||BC817 General Purpose NPN||Q1 Q2 Q3 Q4|
|1||RWS-371 433.92Mhz RF Receiver Module||X1|
|4||Finder 40.51 12V 10A SPDT Relay||K1 K2 K3 K4|
|1||1×6 2.54mm pitch 15mm height Male Header||J7|
|2||1×8 2.54mm pitch 15mm height Male Header||J5 J6|
|1||1×10 2.54mm pitch 15mm height Male Header||J8|
|4||1×3 5.2mm pitch Screw Terminal Blcok||J1 J2 J3 J4|
Please feel free to ask your questions and share your comments by using the comments field below.