PICAXE VSM - Clunky or me?


New Member
Just thought I would add a quick post here as I have not long ago purchased VSM.

I come from using Circuit Wizard (which obviously doesn't support the PICAXE and is purely general components) and now I am getting back into PICAXE I thought VSM would be a great addition for testing things before building them for real.

It may well be me as I am new to using it, but so far I have found it quite difficult to use and fairly non-intuitive. For example, I thought I would start with something very simple just to get used to the software so I created a circuit with a 12v power supply (most of the stuff I do is on 12v) with a 5v regulator, a switch and an LED/Resistor. When you press the switch, the PICAXE detects you are pressing the switch and turns the LED on. The LED anode is connected to 12v and the cathode to a PICAXE output pin via a transistor. This is not about the circuit, as I have a fully functioning version of this so it is just purely to learn VSM. Even setting up the power supply was long winded. I am used to just dragging a power supply on to the screen editing it's properties and saying 12v or whatever. I could add as many as I wanted and change the voltage there and then. On VSM it seems you have to go in to a completely seperate menu to do it and is made quite confusing when you get there. It even took a while to get used to the fact that on some components, pins were hidden. On all the components there is a line on the screen that reads '<text>' but I haven't worked out how to edit that yet.

Firstly, the LED doesn't turn on and off even though there is a red-dot next to it to say it should be on (or I assume that is what the red dot means). Then I find by the internet that I have to use a different component LED-RED. Now when I press the switch, the LED goes red but when I relase the switch it stays on (even though the red dot disappears). Looking in the tutorial, all it seems to mention about LEDs is using the decompose function. In circuit wizard all I had to do what select an LED (which I could change in the properties for colour and other parameters) and put it on my circuit.

There were a number of other things I couldn't figure out either. In Circuit Wizard I could point the mouse at anytime to a wire or component pin and it would tell me the voltage and ampage at that point live. If I do that in VSM it says I have to pause the simulation to measure or I have to add a DC voltmeter there to see it live. Not sure I understand why the simulation has to be suspended just to see the voltage.

I also couldn't work out how to run the editor to edit/create a .bas file. I found the option that says setup external editor but couldn't find any option where you say use it so I don't have to keep opening notepad editing, saving and closing it down.

I am sure this is probably a wonderful piece of software when you get going with it but first impressions are that it is very clunky to use. I wanted to use the voltage indicator but couldn't find anything anywhere in the documentation on how it works. Everytime I used one it always gave se some sort of error such as no source or nothing to measure or something like that.

I don't want anyone to think I am complaining as I am very new to VSM and with anything, there is a learning curve but it just seems it has been designed to make it as difficult as possible to use.


Technical Support
Staff member
VSM is extremely powerful software, so does have a learning curve to get used to how the advanced commercial grade SPICE simulation features operate. Some common SPICE concepts (like generally using 'power nodes' instead of a 'power supply') also need to be learnt, but it doesn't normally take that long to get used to the main principles.

There are a large number of PICAXE demo circuits so try running them first to learn how simple components like LEDs simulate (almost all the samples use an LED). Access theses samples directly via the Help->Sample Circuits menu.

Also take a good look at the right click context menu, which is a very powerful shortcut to most common features.

For instance to:
- add a power nodes right click -> Place -> Terminals
- add current/voltage probes right click -> place -> voltage probe / current probe
- add an instrument (oscilloscope, meter etc) right click -> place -> virtual instrument

Once you have allocated a source file to a PICAXE chip (via the Source->Add menu) it's filename will appear at the bottom of the Source menu. Simply double click on the filename to launch it in the in-built code editor. Again all the sample PICAXE files show how this process works.