Control relay via ethernet to tcp/ip


#1

I have a relay board hooked up now using my GPIO pins and wanted to add a 8 channel relay board but use a sainsmart Ethernet controller. It is hooked up to the pins on the relay and is turned on using an http ip address, port and a number to turn it on and off.

Is this possible to do now or can it be added in the future?

Or do I have to connect to relays using gpio pins only?


#2

Can you post a link to the device you are using? If it supports MQTT it will work.


#3

https://www.sainsmart.com/sainsmart-ethernet-control-module-lan-wan-web-server-control-with-rj45-port.html

https://www.sainsmart.com/sainsmart-8-channels-wifi-network-i-o-controller-for-arduino-relay-android-ios.html


#4

Hi Thanks tad.dvor, It is the first link posted on above post but I don’t see anything about MQTT on it anywhere.


#6

Definitely possible, however it will require quite a bit of custom code. Are you using a Pi or Arduino?


#7

Hi,

I am using a pi. It would be awesome to make a call to http work as well as gpio pins. The you can use a wired or wireless relay board and control it.

Joe


#8

So, looking a bit more at the module and knowing you have a Pi that leaves us with the MQTT API. You can do everything in python fairly easily. Here are some ideas for you:

For the sainsmart side of things you will need a web requests library urllib
For the Cayenne side, you will need the MQTT API library

Set up a generic digital output on the dashboard and in the callback in the python code set off a web request for the corresponding relay.

Let me know how you make out with that or if you need any help!


#9

Hi Adam,

So are you saying that on the sainsmart side the urllib? Is that running on the pi or am I setting it up on the sainsmart board?

Joe


#10

You can do all the programming on the Pi in Python. According to what I read you can enable/disable the relays with web requests like:

http://192.168.1.4/30000/00 : Relay-01 OFF
http://192.168.1.4/30000/01 : Relay-01 ON

So you can use the urllib to make the requests and MQTT to communicate with Cayenne.