Hi,

using Node-RED - trying to MQTT listen to input state changes of an IO-4 v2 bricklet having a push-button connected to channel 1 configured as input pull-up.

Issue: When pushing the button, no MQTT message is received - see 2).

Tested first in the Brick Viewer 2.4.11 and the value changes for channel from low to high when pressing the push-button.

Node-RED Nodes Configuration

1) mqtt in with topic tinkerforge/#. Messages are received (see below test channel 0 as output)

Tested OK (MQTT message received) the IO-4 state change of channel 0 (output) - led connected - using in a function node with msg.payload input true or false

//Bricklet: IO-4 - Example to set pin 0 high | low
var brickletUID = "G4d";
var topicPrefix = "tinkerforge/request/io4_v2_bricklet/";
var topicSuffix = "/set_configuration";

msg.topic = topicPrefix+brickletUID+topicSuffix;
msg.payload = {"channel": 0, "direction": "out", "value": msg.payload};
node.status({text:"State:"+msg.payload.value});

return msg;  

2) Channel 1 as Input with a push-button connected.

Configured a function node as follows - no MQTT message received when pushing the button

//IO-4 - example set callback configuration
var brickletUID = "G4d";
var topicPrefixRequest = "tinkerforge/request/io4_v2_bricklet/";
var topicPrefixRegister = "tinkerforge/register/io4_v2_bricklet/";

msg.topic = topicPrefixRequest+brickletUID+"/set_configuration";
msg.payload = {"channel": 1, "direction": "i", "value":true}; 
node.send(msg);

msg.topic = topicPrefixRequest+brickletUID+"/set_all_input_value_callback_configuration";
msg.payload = {"period": 0, "value_has_to_change": true}; 
node.send(msg);

msg.topic = topicPrefixRegister+brickletUID+"/all_input_value";
msg.payload = {"register":true}; 
node.send(msg);

msg.topic = topicPrefixRequest+brickletUID+"/get_configuration";
msg.payload = {"channel":1}; 
node.send(msg);

What is wrong in the configuration?

Hi,

msg.topic = topicPrefixRequest+brickletUID+"/set_all_input_value_callback_configuration";
msg.payload = {"period": 0, "value_has_to_change": true}; 
node.send(msg);

A period of 0 disables the callback, you have to set it to (at least) 1.

Got it - overlooked the documentation "A value of 0 turns the callback off." = got mis leaded by the default value 0 (period – Type: int, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0).

After changing, its working fine.

Thanks for the swift help.