Author Archives: Ian

FreeCAD Beginner Series

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Keeping up with the changes

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It’s been a while since we posted a new update. FreeCAD has become our go-to CAD/CAM package. It’s working out nicely as a tool to create 3D models for either CNC routing or 3D printing. The Path module is good but not 100% complete yet. It continues to improve with time.

We are working on creating some helpful videos for other users that want to get the most out of FreeCAD and their maker experience. Check out our channel

MPCNC inlays

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Iron Man

I am still working on creating a flawless inlay. I have found some wood that I can use but now I have to find a good subject. I am starting to get a feel for the type of graphic that would make a good inlay candidate.


Take a look at this page MPCNC vcarve inlay technique it should give you a good idea of where I am with this.

I have created some videos on the subject you can find them here YouTube video

Blender 2.8 Video Green Screen

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Using Blender 2.8 it is possible to create a “green screen” video. Essentially you record a video in front of a green screen then superimpose that video over another background. To do this in Blender is fairly simple but you have to know what you are doing. It’s certainly not intuitive.

This picture shows the compositor window it’s important to understand that Blender has many different work benches in which you can manipulate “things” The compositor window allows us to take the source and apply nodes making it possible to filter out the green screen. This blog is just showing the very basic process of making a green screen video. It’s not intended to be perfect and much of the “tweaking” will depend on the final video used.

Here you can see three work benches are open the video editing, the rendering, and the compositing. You can switch between these work benches but for now it’s only necessary to use the compositing work bench. If the compositing work bench is not open, click on the + to the right and select compositing.

When you check the use nodes box (see previous picture) you will be presented with a rendering node and a composite node. You can delete the rendering node as we are not working a rendering as our source. To delete it, right click on the rendering node and select delete.  Instead we are working with our green screen movie. Click add then input from the menu and insert a Movie Clip node. To place the node just move the mouse and left click in the position you want it to stay. It doesn’t really matter where you put it but input is usually left to right. At the bottom of the node you  can see a file search box. Click that and select your green screen video. Of course at this point the green screen video is just something in front of a green screen that you can see, no magic has been applied.
Now add a keying node. You can find that under the Matte menu item. You will see that the keying node will allow you to select many different adjustment factors. More on this later.
Now connect the image output of the green screen movie clip node to the image input of the keying node. Don’t adjust anything yet, there are more nodes to add that will make the adjustment easier. Now add an Alpha Over node, you will find it under the color menu. Connect the image output of the keying node to lower image input of the Alpha Over node. You will see why later.
Finally add viewer node now connect the image out from the alpha over to the image input of both the composite node and the viewer node. This will show you the green screen picture in the background. You can adjust this image to make the green screen disappear. To start you will need to go back to the keying node.

Here you can see an item called Key Color. Click on the color and choose the color picker (pipet) and select a darker portion of the green screen in the video image. This will set the key color so that Blender will try to remove it. Now you can tweak all the settings in the keying node to try and make the green screen disappear. – You should wait for the change to render before you try another tweak. Eventually you may add other nodes to assist with removing the green screen but for now, let’s keep it very simple. Once you have the green screen removed (in my example it’s not quite gone but I don’t want to be perfect here just get the principle worked out.Now we can add a second movie clip node, this will be our background. It can be a static image or another video. The choice is yours. Once you have added the node use the file selector to insert the media you want to use. Make sure that it is large enough to fill the background. If it is not adjust it before you use it.

Once you have the media loaded in the second movie clip node just connect the output of that movie clip node directly to the upper image input of the Alpha Over node. This should put your image in the background.Before you render the video you need to make sure you have everything set up properly. The output should look like the picture above. Select an output folder and ensure you have ffmpeg video selected or it will just render frames. Select RGB for color output and an MPEG4 container. Make sure your end Frame is the end of the video you want, too short and you won’t get it all, too long and you will have a lot of black. And finally, and most importantly. Blender will by default render the sequencer (video editing work bench) you need to select just compositing in the post processing. Then just render the animation. I normally render the image first just to make sure it’s rendering what you want to see. Rendering takes a while, go get a drink and come back later and you should have a video in the output folder that you selected. You can take that video into the video editing work bench and manipulate it like any other video.


If you want to use a box matte to remove areas of the video that are not on the green screen. Ensure you connect to the garbage input on the keying node. The box matte node should connect right after the movie clip node and before the keying node.

Home Automation

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As you may have seen I have the Amazon Echo at home. I liked the potential to make the echo the hub for home automation. The first step is to get something you can control so I set out to find something that works with Alexa natively so there would be no issues with integration. I searched Amazon for the a switchable plug that I could plug my living room light in to. I found the TP-LINK HS100.打印

This is a wifi enabled smart plug. You plug it in and from an Android app set it up on your wi-fi network. Once it’s set up you just ask Alexa to look for new devices and it will find the smart plug. Through the set up you designate a name for the device so now you can say something like “Alexa turn on the living room light” and it will switch it on and say “OK”. This is cool and how I work my living room light today. Of course the light is just one thing you can turn any item on that is plugged in to the smart plug. It is just a simple way to power on and power off. This is the beginning of automating the home of course, the smart plug is about $30 so this could be an expensive way to avoid turning a light switch. I will admit that I got mine a lot cheaper than that, it was on sale and I had a gift card from a survey so I ended up paying about $4 out of pocket.  Since we have had that light operated by Alexa we have wished that we had one for the bedroom light so that it would be on when we go upstairs. Now imagine, instead of saying “Alexa turn off the living room light” at the end of the day we could say “Alexa its bed time” and have her turn off the living room light, turn off the tv and the tuner, turn on the bedroom light, set the alarm, check the garage door is closed, and start the sounds of the sea music. – Well, this is possible if you introduce something like Openhab. What is this you ask, here’s a brief description of Openhab

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Cat Wheel Chair

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I met a sweetheart little cat who had been hit by a car and injured his spine. Regardless of this horrific injury he is a lively and inquisitive little fellow that can move his front legs and scoot around on his bottom. This can cause issues with wear and tear on his rear end. His back legs appear to have some feeling but are not working as they should. He needs a “cat wheel chair” so I thought how can we create something light enough, strong enough and cheap enough that we can make it a reality for him. How about some some plastic plumbing pipe and pair of wheels?


Here’s the first attempt. The idea is his back legs will sit in the sling and the front of the wheelchair will be attached to a harness.



Here he is trying it on for the first time. It needs some adjusting, it’s a little too tall for him yet. We will get that right and do a final fitting then hopefully, he will be able to move himself around without hurting himself.

Great news! Thanks to the dedication of the folks at Hoof and Paw Vets this little guy is able to walk again…  Just look here.



The Amazon Echo

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I saw the Amazon Echo online and thought that it looked like a cool device, it’s essentially a smart blue tooth speaker. How is it smart you ask? Well, it can understand some of your spoken questions/commands. Take a look at the Amazon page here Amazon Echo

Or simply search for Echo on – I was intrigued by the capability and wanted to see how hard it was to build an “Alexa” skill so I researched a little and it turns out that you build a skill from a template. Although that sounds simple, it’s anything but simple. There are several parts to the creation and publishing. I decided to create one that could provide some car insurance facts. The template gives you all the code that you need you just need to carefully follow the instructions and replace the key words and facts with the data you want to share. Having done that I was able to successfully publish my first Alexa skill and it is now available from the ever growing skills library on Alexa.

feature-setupYou can ask Alexa things like, “what’s the weather today?” or “give me an update” and it will give you whatever it can. You can also ask it to add things to your shopping list which can see on your phone when you are at the store. It’s very cool that way. Where it really falls down is it’s not linked to a regular search engine so if you ask it something that you think Google can answer you may stump Alexa! It is improving daily, there are more “skills” being added daily. I am very interested to see where this technology goes. I suspect that Amazon is going to integrate Alexa into many other devices.

One of the other cool features of Amazon Echo involves home automation. You can use “Alexa” to automate things at home check out my page on home automation.