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:

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


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).


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

April 14, 2013

Sous Vide Part 2: The Early Version

In part 1 of this post I talked about what sous vide is and a little about how it can transform foods. I'm not going to delve into the world of opinions on how fantastic it is, unlocking unheard of flavors, tenderness beyond belief, etc etc. I assume that if you've come this far on the internet you've already read a lot about all that, so I don't need to convince you. Instead, I'll lay out my experience tinkering with my homemade controller, how I did it, and how you can do it, too.

April 13, 2013

Raspberry Pi Thermostat Hookups

I recently replaced my thermostat with my Raspberry Pi. In this post I explain how to make the hardware connections between the Raspberry Pi and the house wiring. Check out the Makeatronics Store if you want a PCB that does the connections for you.

In my house (and the vast majority of others) the thermostat wiring runs at 24V AC. There's a live wire (or two, depending on the setup) coming into the thermostat, and several others leaving to control the different components of the HVAC system. The thermostat's job is to close the circuit between the live wire and the appropriate control wire based on the temperature. A relay is an easy way to do it, but I find relay's cumbersome with their (usually) breadboard unfriendly pin layout and larger-than-can-be-supplied-by-gpio switching current requirements.

March 14, 2013

Little Wire SMD

I came across the Little Wire a few months back. I thought it was a pretty cool idea to have a few GPIO's accessible over USB. More than that, it also offers several serial protocols (I2C, SPI, etc), dual channel ADC, and even works as an AVR programmer, all in a neat little package! To make it even littler, I designed an SMD version of it.

I especially liked it for using a software implementation of the USB protocol on an attiny, which means I should be able to use an attiny in place of the much larger (and more expensive) FTDI chip.

March 3, 2013

(Mostly) Organized Resistors in 20ish Drawers

Organizing electronic components is important if you want to spend more time building prototypes than looking for the right resistor. The problem is, there's just way too many to organize without spending a ridiculous amount of money and space on a billion little drawers....