Styjun

I'm trying to read out 5 microswitches in LuvitRED (other form of node-red). To be useful in the rest of the program, the 5 sensors should come together into 1 integer.

The image above is the layout for the node-RED. At first, I was going to convert each input in a separate function. The bottom part shows the second idea, where all microswitches are read and summed in 1 function.

The idea is:

• Microswitch 1 = 1 (when active)


• Microswitch 2 = 10


• Microswitch 3 = 100 and so on.

This way, when I summed them all, the eventual number would be between 00000 and 11111 depending on which ones are active and make for easy recognition of which microswitches are active.

The bottom part of the image is using simple buttons, which all send a msg.payload = 1 when pressed for quick testing. The code for the function is mentioned below here.

I Googled about this problem, and a lot of the forums stated that using the change function (to change 1 to 10 and more), combined with the join function would work. Sadly however, in LuvitRED, there is no join function, because it is an altered version of Node-RED.

if not msg then
-- called on startup
return
end

flow.microswitch1 = 0;
flow.microswitch2 = 0;
flow.microswitch3 = 0;
flow.microswitch4 = 0;
flow.microswitch5 = 0;

if (msg.topic == 'microswitch1') then
 flow.microswitch1 = msg.payload;
 elseif (msg.topic == 'microswitch2') then
 flow.microswitch2 = msg.payload * 10;
 elseif (msg.topic == 'microswitch3') then
 flow.microswitch3 = msg.payload * 100;
 elseif (msg.topic == 'microswitch4') then
 flow.microswitch4 = msg.payload * 1000;
 elseif (msg.topic == 'microswitch5') then
 flow.microswitch5 = msg.payload * 10000;
end

global.availableSpaces = flow.microswitch1 + flow.microswitch2 + 
flow.microswitch3 + flow.microswitch4 + flow.microswitch5
msg.payload = global.availableSpaces

return msg

I expected this to work, since I'm only working with buttons for now, which always send a 1 msg.payload when pressed. For some reason however, I'm getting an input error when pressing the buttons without any result in the debugger. Do you all have any ideas as to how I can fix this issue?

On the assumption you cannot use a join node (which would be the normal way to do it), you might be able to use flow variables. Although you would need to check if LuvitRed supported flow.get and flow.set and if it has persistent storage between restarts.

When reading the microswitch you would then just save it to a flow variable:

flow.set('microswitch1', msg.payload); // or however you're getting the value

Then each line in the func would be along the lines of:

var microswitch1 = flow.get('microswitch1') || 0;
// etc

This way, if microswitch2 hasn't changed yet, it will use 0 instead.

But the upshot is you need to cater for the final func being run on every individual message it receives. The only way to wait for all messages is to use a join.