August 18, 2014

Smart BLDC Commutator For Sale

The wait is over, the Smart BLDC Commutator is now available for purchase in the Makeatronics Store.

Unlike my other boards so far, I am not (yet) offering this one as a complete assembly. It's all surface mount and takes too long for me to assemble them myself. I am working on getting a stencil made so I can reflow them in my hacked toaster oven.

Thanks for checking in!

August 8, 2014

Smart BLDC Commutator - Hardware

Of all my circuits to date, the Smart BLDC Commutator is probably the one I'm most proud of. To those coming here for the first time, this board is for driving brushless DC (BLDC) motors. I spent a lot of time researching and prototyping to come up with this board. If you are trying to figure out how to drive a BLDC motor I think you will find the information below very helpful.

From a high level, I wanted an interface to a BLDC motor that behaved much like a H-bridge does for a brushed DC motor. The result is a board that handles the heavy work of commutating of a BLDC motor using hall effect feedback. After hooking up power, motor wires and hall sensors, the minimal inputs required to the board are direction (high/low) and PWM. Everything else is taken care of to properly spin the motor. Pretty nifty.

August 5, 2014

Scrap Yard

Check out the new Scrap Yard!

The process of making good designs often includes a few mistakes. Sometimes I'm lucky and get things working on the first try, but more often it takes two or three revisions to get it there. And since the PCB manufacturer I use has a minimum order quantity I end up with a fair amount of scrap.

Rather than throwing them away, I've decided to sell the extra boards at discount price. It's up to you to get them working. I will provide details of fixes I have made to get them functional, just click on the images to be taken to the details.

Obviously, I have a limited quantity of these boards. Once they are gone they will be deleted from the scrap yard never to return. Check back as often as you like, this page will be changing as I embark on new (and revisit old) projects. 

August 4, 2014

Smart BLDC Commutator Coming Soon

I recently received a small batch of Smart BLDC Commutator boards to verify V3 routing. I'm pleased to announce that it tested flawlessly. I made a few changes to the silkscreen, including some equations to the back side to help in using motors with voltages outside the current design limits, and placed an order for a larger batch.

I expect boards to be in by the end of August 2014. After a quick overview to make sure all is well I will put them up for sale in the Makeatronics Store.

Once I get some time I will write up a detailed post on the hardware changes and the firmware running on it. Until then, here's the schematic if anybody wants to benefit from my experimenting.



Design files are hosted on GitHub and licensed under CERN OHL v.1.2.
Firmware is hosted on GitHub and licensed under the BSD 3 clause license.

July 27, 2014

Wireless HVAC Sensors - Part 2

Previously I introduced the idea of a battery operated wireless sensor board for sensing temperature and humidity. The intent is to get information to my Raspberry Pi (or Arduino, or any other microcontroller) so that it can intelligently control the HVAC system in my house. Today I give you an update on the project.


May 18, 2014

Makeatronics Store Now Online

Up to this point all products I've put up for sale have been so only through the blog post that described them. This quickly got confusing and cumbersome as I've slowly finished more projects and released them for sale. Now I've built a simple store to host everything. Blog posts where things used to be for sale have been updated to point to the store.

Up to now I have only offered a few bare PCB's for sale. I am now offering the PCB's with loose components and fully assembled products. As time goes on I hope to also have mechanical items available (think 3D printer parts) plus who knows what else.

If you like the projects you see on this blog the best way to support is to make a purchase in the store. Funds received through sales have a direct impact on the time and money I can spend on new and exciting projects.

Without further adieu, follow this link to the store:
makeatronics.blogspot.com/p/store.html

May 4, 2014

BLDC Hall Effect Sensors

So I've had two posts now where I talk about adding hall effect sensors to a BLDC motor. I figure it's time to explain a bit more how the process works.

This method only works with an outrunner style motor (that is, the rotor spins around the outside of the stator) with the magnets exposed on the underside of the rotor, such as this:


BLDC Motor Control

As part of my 3D printer project, one of the big electronics hurdles to overcome was a motor controller for a BLDC (BrushLess Direct Current) motor. Searching for a cheap, off the shelf controllers that would interface easily with a microcontroller turned up fruitless, so I took the opportunity to design my own circuit. It was a major project in itself, and while there's still a few hardware tweaks to make I'm quite happy with how it has turned out.


January 12, 2014

3D Printer Motor Control - Part 1

So I've been moving forward with my 3D printer plans slowly but surely. I've mainly been focusing on the drive axes up to this point, more specifically the details of controlling the motor. As outlined in my 3D printer post, I am planning on using closed loop position control with brushless DC (BLDC) motors, rather than the standard open loop control with stepper motors.

October 19, 2013

Wireless HVAC Sensors (temperature and humidity)

As I've been working to transition control of my HVAC systems over to my Raspberry Pi there has always been one big hurdle to overcome: how to I get the temperature reading from the room I'm interested in to the Raspberry Pi in the basement?

August 24, 2013

IR Remote Repeater

Last year I installed my TV on the wall. I really liked how it turned out, but I didn't like the look of cables running up the wall from my DVD player. So I put a recessed box behind the TV, routed the A/V cables through the wall and stowed the equipment in a nearby closet. It cleaned up the look of the room a lot, but there was a hurdle to overcome: how to I control the A/V equipment with a remote? I needed an infrared (IR) repeater to pick up the signal near the TV and repeat it in the closet where the media equipment is. I know there's commercial solutions to this problem, but I figured it would be easy enough to build my own.

August 20, 2013

Building a 3D Printer

I've decided to do it. I'm going to join the ranks of those who have a 3D printer in their homes. While having the ability to print custom parts for future projects will be a definite benefit, I must say that the lion's share of the fun will be in the making of it.

Now, I know there is no shortage of plans and designs available for DIY 3D printers contributed to by a community of makers, hackers, hobbyists, etc., I've decided not to go with an existing design. My schooling focused on robotic kinematics and control as well as mechanical design. It seems a shame not to put that learning to good use. Perhaps I'll blaze some new trails in the process.

June 23, 2013

24V AC Solid State Relay Board

My post on the hardware connections between my Raspberry Pi and HVAC wires has become one of my higher traffic posts so far. Apparently people are searching for ways to connect Raspberry Pi's to thermostats (or Arduino or any other microcontroller for that matter). So I decided to design a circuit board to fill that space.


May 12, 2013

Sous Vide Part 3: Advanced Development

In part 1 I introduced the concept of sous vide and why you should be interested in it. Part 2 covered a basic and low cost way to get your feet wet with sous vide. Today, part 3 will detail the more advanced stand alone controller I designed.

April 29, 2013

Thermostat Software

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EDIT: I don't profess to be a programmer, even though I can make my way through a few different languages. The code I present here works fine, but it's not very pretty or efficient. I think it's still useful from an educational standpoint and has a few ideas in there that are worth looking at and it's easy to get up and running. But I will soon be ditching this software in favor for some written by Wyatt Winters for his Rubustat (though I'll try to find a way to re-implement the checking of outdoor temperature to determine heating/cooling).

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In this post I explained that I tasked my Raspberry Pi with controlling the furnace and air conditioner in my house. Here I describe the software that went into it.

The requirements I wanted were simple enough:
  1. Behave similarly to a commercial thermostat
  2. Schedule temperature set points
  3. Automatic switching between heating and cooling based on outdoor temperature