midTbot

thingiverse

This is a compact pen drawing bot. It's similar to a T-Bot, but I've repositioned the motors to the center. This has the advantage of reducing its size and making it even more attractive, in my opinion. Check out the video. <iframe width="560" height="315" src="https://www.youtube.com/embed/AB4bb1G7DIs" frameborder="0" allowfullscreen></iframe> I built mine with a small footprint so it can fit easily into my backpack, but it's simple to scale up by using longer rods and a longer belt. However, keep in mind that the X-axis rods may start to flex above 200mm long. The firmware is a customized version of Grbl. The only change made is that the spindle PWM is used to raise and lower the pen, and it also has the CoreXY features of Grbl enabled. You can use virtually any CNC controller that supports two steppers and a servo, but I designed a [custom controller](https://www.tindie.com/products/33366583/midtbot-controller/) that sits in the center and keeps the wiring neat. A limited quantity is available for sale on [Tindie](https://www.tindie.com/products/33366583/midtbot-controller/). For more information, check out my [blog post](http://www.buildlog.net/blog/2017/10/the-midtbot-a-new-flavor-of-h-bot/) or follow me on [Twitter](https://twitter.com/buildlog) for updates.