Saturday, May 28, 2011

DC to DC Converter Shield

I had originally planned to send my Relay Shield to the Fab shop this week, but I ran into a snag. Neither Mouser nor Digikey stock the relays I need, and theyre backordered with a 20 week lead time. =( So Im left redesigning my board to be able to take relays with any power requirement (specifically the 12V relays). What that entails is that the power requirements wont be on-board. There will be a shield (which it plugs into) that will convert the regulated 5V of the Arduino into 9, 12 or 24V depending on the power requirements of the relays used. Im designing the shield with my project in mind, but anyone with various power needs will be able to use this shield. I'll be sure to include a resettable fuse in there just in case (though I dont think you'll need it, because if something happens to break the fuse, your board is probably dead by then).

Once I get these two shields wrapped up and to the shop, I should have an operating power control unit that I can work with for switching lights on and off. You might be thinking, why bother with all of this work? Isnt there an existing board you can just buy to use? The answer is no. The relays I've found on SparkFun, and other places arent reliable to be switching your lights for your home on and off. If you want take a risk, feel free to use them. I personally dont want to burn my house down experimenting with this project, so I'll build it the only way I know how: the safe way. Second, the relay boards I've found dont offer the features that I want. The board that does offer it is made by a company called NCD Relays. I have experience with their boards, and theyre pretty cool, but on the downside theyre expensive. I can afford a bank of these boards throughout my house. I'll go broke before I've finished wiring the house. So I needed a cheap way to give me the same features, but for use with an Arduino, thus I'm making these boards myself.

Nothing new for the other parts of the project. As usual, I'll post various links of projects, and hardware sites I think are relevant and useful to my project.

Sunday, May 22, 2011


Well I got so into the concept of designing my very own prototype, that I got sidetracked from the original task. I just now realized this. On the other hand, I managed to get very far in the design process of the next phase of the prototype (the custom boards). So when I actually get to that stage, I wont have to work very hard. ^_^" 

Back to work on the testing phase of things. I still have to setup the Arduino with the Gas sensors to send data to the LAMP server. If I can get that to work, it'll be a major step. Sadly, Im working alone on this, so things just have to run their course. Being sick doesnt help either. 

Just to keep you folks updated on what I've been working on, I've made the conclusion that the system will contain 3 different power and communications protocols:
  1. Hard power & hard-line communications (ethernet)
  2. Hard power & WiFi communications
  3. Self-Sustained power & WiFi communications
So these 3 protocols are what I'll be using for the various systems. If a module is closer to the outdoors, it'll have a solar panel, and WiFi. If its somewhere indoors, but you cant get to it for cable management, then WiFi and a power adapter from where it is (Hard power).

I've decided that I'll make this entire system open source and open hardware. What that means is that developers who want to build on my system are free to do so to their hearts' content. Users who arent tech-saavy will probably not care that it is open source (other than security, but its offline so no worries yet). Source code however wont be plastered all over the internet, so that shouldnt be a problem. There will be extra features (plugins) that will expand on the base system that will give users and developers alike expanded options. Those will be for sale. For example, a system in a two-story house has 2 modules per room, 4 bedrooms, 3 sitting rooms, and a kitchen. Thats a total of 16 modules in a home. That gives you the fire detection system, and the smart lighting system. Since I've discussed home security as well, the system would include a base of say 4 camera's around that 2-story home. Thats the base package. Say you want to detect an intruder before they enter your home, thats an extra feature. 

I've got lots to do, and this is just a vague explanation of what you can expect to see out of this, but dont hold me to it. Things can change, and this plugin concept is all very new to me. 

Of course, this is all assuming that an Arduino Uno boards are used in combination with custom shields (I'll be selling those). For space requirements, I'll have to resize things and use the prototypes I was designing to make some custom microcontroller boards that have a small footprint. Arduino's are made for hobbyists who want to fiddle around, or amateurs who want to create prototypes (like me). So, I dont really want to come across to consumers that the hardware protecting their homes (and keeping them energy efficient) is hobby hardware. Creating my own is the key. Thats Phase II.

While I had intended this to be an update post, it has sort of turned into a "relieve-yourself-and-get-it-all-out-there" post. Haha \(^o^)/ I do that at times. Im just excited that I got a board sent off to the Fab Shop, because that one is the Teensy DC Relay board I was working on. The AC Arduino Relay shield has been completed, but I have to wait a few weeks until after Memorial day to get it sent to the shop. Once I get that shield, I can start fiddling with switching a light on and off based on a person being in a room.


I've ranted long enough. Take care till next time. Ѡ

Saturday, May 14, 2011

PCB Progress

Well good news. Ive managed to work on and finish four PCB designs: a Relay Shield for the Arduino (rated for 30A & 220VAC) , and a smaller relay shield for the Teensy 2.0 (rated for 2.5A & 60VDC), both of which would be very useful for the Smart Home System. The third shield is a 3-Axis Accelerometer Shield, and finally the fourth is the compass shield. Going to put those aside until I can save up resources to get them made and assembled (I realize they aren't big, but there's more to micro boards then just the PCB's). Ive decided once I have prototypes of these in my hands, I'll post pics of them, along with Schematics, so stay tuned for them.

Thanks to Paul, from PJRC, for suggesting the idea of creating a USB Host Controller Shield for the Teensy 2.0 for the use of multiple USB devices. Theres a chance I can even get the Teensy to run a Bluetooth dongle too! Awesome stuff. Lots of ideas brewing from that, but since its not related to the Smart Home Project directly, I'll see if its possible to integrate it in-Bluetooth controls of home settings, or something.

A note on electricity management/fire prevention module: Ive decided to use shunt-trip breakers in cooperation with the smart plugs so that if the smart plug fails to trip, the main breaker will trip. I've also decided that for the prototype smart plug, I'll use a Teensy 2.0 with my custom relay board. The plan is to eventually integrate the Atmel Microprocessor onto the relay board in a compact package that will fit in a standard size electrical gang box. Im also considering wireless communication (802g wifi) for these, along with some micro or mini dc adapter (120VAC to 5VDC with a regulator & battery) that would allow this module to fit in that box. The goal is that they should be self-sustained and zero maintenance.

Onwards, I'll be working on the Gas Sensor Shield, the Gas Sensor IC Board, and I'll devote more time to getting the server operational.

Live long and prosper.

Friday, May 6, 2011

PCB Development

Well Ive been busy with final exams lately, but what time Ive had has been devoted to creating custom Eagle libraries for all the parts for designing my PCB boards. Im almost done designing the Arduino Gas Shield and a Dual-Relay AC Power Shield (which uses G8P Relays from Omron). While the Gas Shield will be for the Active Fire Detection System, the Relay Power Shield (Powerduino v1.0) will be for AC power switching for lighting controls, as part of the Smart Home system. Once everything looks good, I think I'll upload both shield Gerber files to Batch PCB (and post the Bill of Materials here) for those of you wanting to buy the boards and build the kits yourself (I'll see if Sparkfun can carry these two also). 

For a future board, I tracked down a solid state MOSFET relay with a current rating of 2.5A that would be wonderful for a micro-sized DC Power board for use with the Teensy and Teensy ++. I'll design that when I have the opportunity. That would probably have a use in the alarms for the Smart Home System.

So there are many mini-projects going on simultaneously for the Smart Home System, as Im the lone person working on this. Hopefully I'll have something to show for all this work by Summer.

As an update on the Arduino/Efika side of things, Im having to reinstall Ubuntu on the Cloud server because of a glitch in the software thats now preventing me from having admin rights to edit anything. The Arduino Gas Sensor part of it is somewhat on hold until I sort out everything with the server. With all thats going on with my final exams, and the PCB boards (you can tell Im really bouncing around), I'll get to this when I get to it.

Stay tuned for updates.