The March issue of Circuit Cellar Inc magazine is out and it features an article I've authored about the canvas painting machine I built a while ago. A video of it was also included here.
It all started when I learned about another project on the net. However, though I have tried to contact the authors they've never answered any of my emails.
Variable Frequency Drives ( VFD ) allow the control of spindles so speed can accurately be controlled and a detailed acceleration profile for the spindle and reverse rotation can all be handled. In essence a VFD is an three phase inverter for three-phase AC motor. I am using a popular (I mean cheap) Chinese VFD and though the reference manual is not great, I could see there is a built-in RS-485 port. I usually control the start, stop and speed selection using the keyboard on the unit but I thought it will be more useful if I could control everything from the same Arduino is doing our CNC table control. Some cheap RS-485 off eBay and some lines of code later, I can start, stop and change the speed from an Arduino. What a cool thing to have! Some configuration of your VFD are needed before you can use it like that. You need to set PD163=1 (I am using address 1 in the code). PD=164=1 (for setting serial to 9600bps) and PD165=0 (for using ASCII and 8N1 character for...
I recently saw the cool mood lamp by Philips and I liked it. What I did not like was the price. I set myself to discover what the industry has to offer in terms of high-power LEDs. It turns out that since the old 20mA red LEDs the market has evolved in such a way that it seems the light appliances of the future might be completely LED-powered. Now there are 3W and 10W LEDs available. Either monochrome or RGB. I like LEDs as they last forever (I've never seen a LED that stopped working unless it was due to a current overload). High power LEDs are not cheap but they are very easy to control from a micro-controller using PWM (Pulse Width Modulation). They need DC low voltage power sources. I did a test with an Arduino board and a protoboard with a ULN2003 that I've used to control a 3W RGB LED . I programmed a never ending random sequence and this is the source code . Just connect each led (R,G,B) to the outputs 9,10 and 11 of the Arduino. If you need more current then use a Darl...
After watching a video of a new pen plotter made by Evil Mad Scientist we wanted to have a similar device. And having a 3D printer at hand plus some CAD software like Onshape or Fusion 360 it was a good exercise to design the whole thing. As usual the process was not completely straightforward, as initially it was more about copying the model we saw but as things were coming together some new ideas were explored. So while the first mock-up was based entirely on laser-cut parts (some of them glued together to make them thicker as the crappy laser I have access to is really depth limited as it is low-power). Why laser-cut? Well because it was faster (or so it was supposed, but don't get me started on that). Once the first model was put together several ideas pop up: First, motors are in the way of carriage motion and reduce a bit carriage travel along smooth rods. Second, motors require another part that could be fused with the machine feet and rods support. Third, t...
Comments