|Item Weight||2.9 ounces|
|Product Dimensions||7 x 6.4 x 1 inches|
|Item model number||8-CH|
SainSmart 8-Channel Relay Module
|Price:||$12.95 & FREE Shipping on orders over $35. Details|
|You Save:||$5.15 (28%)|
- 5V 8-Channel Relay interface board, and each one needs 15-20mA Driver Current
- Equipped with high-current relay, AC250V 10A ; DC30V 11A
- Standard interface that can be controlled directly by microcontroller (Arduino , 8051, AVR, PIC, DSP, ARM, ARM, MSP432, TTL logic)
- Indication LED's for Relay output status
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Top Customer Reviews
I asked a few questions and they sent full detail along with schematics and layout information.
I'm posting the additional detail they sent. The rest of the pin out information seemed pretty straightforward. Overall it is a neat, compact, durable design so far. We are using it in for HW design test purposes.
Power Supply: 5V DC / 400mA (relay all ON)
Input control signal voltage:
0V - 0.5V Low stage (relay is ON)
2.5V -5V High state (relay is OFF).
Input control signal LOW state current:
JD-VCC or VCC: Power supply input, 5V DC. (JD-VCC RELAY POWER VCC:SYSTEM VCC)
GND: Power supply ground and control signal ground.
CH_x: Control signal input, Low: relay ON, High: relay OFF.
COM / NO / NC: (C1=COM1, C2=COM2)
Control signal state low, the relay ON, COM - NO disconnected, COM - NC connected.
Control signal stage high, the relay OFF, COM - NO connected, COM - NC disconnected
- Connect arduino powersupply 5v to VCC
- Connect arduino Digital ground to ground
- Connect arduino digital output to any IN1-IN8
- You're in business!
I connected my meter in series and found I was drawing 64mA across the Arduino 5v power supply and 1.9mA across the Arduino output pin.
I flipped it over and measured 7100ohms across the coil, meaning the coil is drawing 0.7mA at 5v.
These numbers honestly seem a little low to me - e.g. I expected more like 19mA across the output, but 64mA across the power supply seems very reasonable with all eight relays drawing 400mA per the spec.
Note: Arduino max power supply voltage is 500mA on USB, so you're good there too.
- This won't blow up your Arduino.
- I didn't realize this model had LEDs. I looked at the 4 relay model and the LEDs are bigger, but these are smaller and work great.
- LED's in the circuit act as diodes. My dad told me when the field collapses on a DC coil it generates a negative voltage. If you don't have a diode in the way you could burn up your output transistor.
- This has NC (Normal Closed) and NO (Normal Open) contacts on the high voltage side. So if you want your lights ON or OFF by default you can do that. It has a nice diagram on the board showing how the high voltage contacts are laid out.
- 4 mounting holes on the board if you need to bolt it to something!
- Lot's of fun - you should buy one!
- The header PINs are really nice, but I only have male breadboard jumpers and need to buy some male-female jumpers from radio shack before I can hook this baby up to my xMas light setup!!
The board is constructed pretty well and for the price I was surprised to find that every relay (I bought two boards) was working flawlessly. I love that there are two VCC connections - one for the reference voltage to control the circuits, and one to actually switch the circuits. Because each relay takes 15-20mA to switch, this allows you to connect a separate power supply to the switching voltage and use the arduino to control the inputs. The arduino (at least the uno) will not output enough power on its own to physically switch the relays. By default there is a jumper connecting the two voltages, so you will need to pull that off and connect a separate supply. I had both boards connected and tested within 10 minutes. However, I am very familiar with this circuit as I constructed them myself last year. However, when I did it myself it took me a long time to solder it all and it cost more than simply buying these boards. The other thing I love about these boards is that the relay has 3 connections out where you can set up two separate circuits that alternate when the relay switches. When the relay is "off" (it's resting state) one circuit will be connected and when it is "on" the other circuit is connected. This means you can default your circuits either on or off. The relays I've used before didn't have that feature.
I only have two complaints. There was one loose solder connection on an output terminal that would cause the light on that relay to flicker.Read more ›
Other things of note: For an electromechanical (not solid state) relay, this is very fast. But, as with many electromechanical relays, toggling a module on this unit off/on makes a pretty distinct "click" so you won't want to install it in a location that is sound sensitive (baby's room, for example). If you need silence, go with a solid state relay.
Lastly, please note that (as the product description states) this is a 5v relay, and cannot be triggered by 3.3v.
Most Recent Customer Reviews
Purchased 2 of these to build a greenhouse controller. With 16 relays, I don't expect to use all channels, but will have extra channels in case any of the relays go bad in the... Read morePublished 22 days ago by Stephen L.
This works great paired with a Raspberry Pi and being controlled with GPIO.Published 1 month ago by Amos A
Great product, easy to interface with the raspberry pi. We bought two of these. Used one for our christmas light show and the other for an aquarium controller. Read morePublished 1 month ago by Wintermute
Works great, and is easy to use. Note: if you're looking for something to switch fast, and around people, go with a solid state relay array. Read morePublished 4 months ago by RFK