Category Archives: VSCP

#VSCP interfaces howto

Something that may confuse new users of VSCP is the GUID of interfaces. Looking at the interface above the CAN4VSCP driver have GUID set to


which means nodes connected to this interface will come in with GUID’s


If we look at the GUID’s if this machine we see that they all start with


As of  the spec we know that this is a GUID constructed from an Ethernet address. In this case only four of the six MAC digits is used. The


is the interface id as set by the VSCP daemon and the last two digits are the nickname id for a connected node.

The problem that can occur here is that the interface digits can be different at different runs of the VSCP daemon. The number is just set when the interface is set up and from time to time this setup can happen in different order. So sometime


can be


or even


One can’t tell beforehand.

This is a problem if one want to use the GUID to identify a node. Problematic as this is just what we want in most cases. To trigger on an event from a specific node in a decision matrix the GUID is the item to filter on. Just as in this case

Here we store a temperature measurement in a variable if it comes from a node with GUID


and measurement index = 1

If the interface ordinal  becomes something else like


we are in trouble here as the action (store measurement value in variable) will not be triggered.

If we look at the current driver for this setup it is set to


<!-- The can4vscp driver -->
<driver enable="false" >

The “problem” is solved by changing the <guid> tag from an all zero value (or not defined) to a valid GUID.  If not defined or all zero the VSCP daemon will assign a GUID as of above. But if a valid GUID is set this value will always be used.

In my case I can use


as I have some assigned GUIDs.  The two LSB’s is still used for the nicknames.

After that change the “problem” is no more and I can filter on the new GUID instead which alway will be the same.



#VSCP measurement visualization #IoT #m2m

I just want to present some new stuff I have been working on during the last week. It is still initial work but still quite useful. Also beware. This is JavaScript, PHP and MySQL and I am an embedded programmer. But I have asked for help from people who know these things but got no response so here I go and do it myself as usual. If someone wants to step in and help or even take over this project he/she is more than welcome, I have tons of other things to attend to.

There will be a proper howto and a manual at a later stage.  This document is just some information and a demo.

First: Why?

Answer: I need this for my own use. Actually I needed it because I have two compost containers where I have temperature sensors and I was curious of the temperature in them now in the winter when it is cold. Well I have some other temperature sensors around the house and the office that maybe can tell me something also.

If you know VSCP you also know about the VSCP ux framework. It is really a nice set tools that allows for building fast, reliable, secure and responsive user interfaces with live data. It uses the websocket and the REST interfaces of the VSCP daemon to communicate between ux elements and the VSCP subsystem. We talk state of the art security here, at least if SSL is used. But sometimes it may feel awkward to export interfaces of an in operation/house critical piece of computer hardware anyway. This is therefore another way you can share data. A cloud solution if you like. But something you are in charge of yourself.

To use VSCP mv (VSCP measurement visualization) you need an Internet server provider that gives you a mysql/mariadb database. Most does, at least here in Europe. Well you can have your own server that do this also of course.

Secondly you setup the VSCP daemon to send the data you want to share. This you do by adding a decision matrix element to your local VSCP daemon.

Third you configure what data you want to share by adding some entries in the database.

Your are ready to go.

Now you can visualize your data

This is the temperature outside at my place. With the “select source” at the bottom you can look at the temperature in my office and in the mentioned compost containers. The interface works on different hardware, phones, tablets and computers.  Using iframes you can include it in other web pages. This is live and dynamic data.

This is another way to look at the same information. Some more variants of this may come in the future.

If you instead wants a diagram you have that here for the current day, which is the default. The diagram will update as time goes.  If you prefer to see the temperature 2018-03-16 between 00 and 03 you can of course.

And if you rather want to see the current temperature in my office  it is possible or in the compost 1 container or in the compost 2 container.

But if you rather just want to investigate data this collecting interface may be the best place to get a hold on it.

And there are all temperature measurements here. But don’t be fooled.  Any of the VSCP’s measurement values can be shown.


you say. I want to use my own diagram/Table tool to visualize data. I will not stop you. It’s a free world. If you can read JSON your on

Read the defined seco devices.  SECO = SEnsor, COntrol. Or read the current value for a SECO.  Or read data in a date/time range for a seco.

As I said I will come back with a manual and a howto at a later point. Well a link to the software also of course.

For me the info that the microorganisms in the compost container holds it at zero degrees Celsius or just above was worth the effort in constructing this.