I’m currently testing the different flying modes and soon, Mugen will be upgraded with telemetry and FPV!

My home automation system would be wireless, open, cheap, and based on a low power wireless protocol (low electrical consumption and low EM emission).

As of today, I plan to use :

- A server application hosted on a Beagleboard (because of the low consumption, but it could be of course done on any other enough powerfull and “always-on” device as PC), based on some Raphaël JS /AJAX /Cherrypy / SQLAlchemy / Python mix (so platform & OS independent). A basic USB device (with multi-platform drivers) would enable access from the host platform to the dedicated wireless network.

- Wireless devices, dedicated to interfacing and managing sensors or controllers, they should be easily set up and be cheap.

The cost of the different devices (server wireless interfacing or sensors/controllers) should be kept as low as possible. A target cost of 10 to 15 euro would be great.

The UI and the features list should respect the KISS design principle.

I’ll begin by doing a prototype of the core application with 2 basic devices (temperature sensor and heating control) for temperature & heating regulation.

For this purpose, I won’t use any boost module, they are too expensive. Using two AA rechargeable batteries, I’ll have to deal with a 2V-2.4V supply voltage range, nothing more!

For the same reason, I won’t choose any Zigbee-like protocol for the wireless network. As an example, the cheapest Zigbee module costs $22 at Sparkfun!

I’ll try to use the RFM23 434MHz transceiver from HopeRF instead… The features list is great and it is priced under $5! (and it runs perfectly at 2V). Using a very basic and simple communication protocol, it should be a very good base.

The same approach led me to Microchip microcontrollers for the USB connectivity. The PIC18F14k50, for example, integrates an USB interface for a retail price of ~2 euro. That’s way cheaper that the FTDI or Silicon labs USB modules…

And the latest “XLP” devices from microchip seems to be as battery-friendly as the TI MSP430, so that would be a good alternative too…

(Muta image courtesy of Studio Ghibli, from “the cat returns”/”Neko no Ongaeshi”)

Added a page to share some information about the laser cutting machine I’ve bought…

I’ve updated the toolchain installation procedure and added some notes about M3 prototyping solutions.

I’ve been using my SEGGER J-LINK JTAG debugger/programmer and I find it great, but my licence is a non-commercial one.

Since now I want to be able to sell basic kits one day, if I manage to do something interesting for others, I’ll have to switch to a more open solution, so I bought an Olimex ARM-USB-Tiny.

But switching from the quite stable SEGGER GDB server to OpenOCD scares me a little bit…

On a completely different matter, I’m currently buying my future 50W CO2 laser cutting machine ! There will be smoke ! ^^

In fact, it’s not just one led, but a whole led matrix… ^^

I’ve put up an ARM M3 dedicated page where I will share my “getting started” notes and later my M3 projects.

Right now, my notes about installing the open source development kit (ARM GNU toolchain + IDE + plugins/tools) and building a sample C project are already available.

The packaging is great, everything looks professional, but the sticker on the side says “Only to be opened by geeks or nerds” ! Funny, but a bit scary at the same time…

No manual included, you’ll have to go to TechNexion.org to get some instructions/support… A few basic steps later (put the OMAP 3530 target on the Thunder board, plug in the touch enabled LCD), here is the board assembled :

The following step is to download the Ångström image compiled for the board and prepared by TechNexion, and within some linux distribution, prepare the “bootable” SD card with it (create partitions, format, copy files). The procedure is well documented on the support site.

Plug-in the serial cable (if you have no serial port on your computer, get a low cost serial to USB adapter on ebay – for win7, use this driver with those adapters) and prepare on your computer a serial connection with hyperterminal/putty/teraterm/whatever (115200/8bit/noparity/1bitstop/no flowcontrol).

You can then plug in some RJ45 ethernet plug, insert the SD card and then plug-in the USB which will bring some power to the board and let it boot…

The serial terminal shows the log info. and finally, the touchscreen shows some GUI :

Hurray ! (^_^)

It’s a real pleasure to see such a tiny board running, and everything seems to be ready to do some great things : onboard wifi, ethernet, RF link, audio IN/OUT, DVI, GPIO, UART, USB Host & On-The-Go…

The 4.3″ touchscreen comes from LG. It’s nice and is completely usable with the fingers, as long as you let it capture your input with a little delay of 1/4 to 1/2 second.

The ethernet connection worked great out of the box (using DHCP), I could ssh the board from my PC.

Now I have to go deeper and read what I can found about the linux distributions available for Beagle Board and have a look at the sources of the TechNexion image to understand what kind of toolchain and packages will be needed to start programming…

Edit: Created a Google group about this great kit : http://groups.google.com/group/technexion-thunderpack

Beagle Board

The Texas Instrument Beagle Board appears to me as the perfect base for making some DIY home automation system.

It’s cheap ($150), powerful, it supports a lot of embedded OS, has nearly every interface needed and has a power consumption of less than 2W… Plug in some USB keyboard & mouse, a DVI-enabled LCD and you’re ready to go (with a graphic output up to 720p!). Still being in the world of electronics, the board allows you to use some of its SPI, RS-232, UART, I₂C, GPIO pins for you custom needs. The main drawback I can see about the BeagleBoard is that it’s hard to interface it with small touch enabled LCD modules.

Among the few clones of the BeagleBoard, I’ve noticed the Thunder Pack from TechNexion ($250). It comes with a TTL touchscreen interface and a 4.3″ touch enabled display (among other extra features).

With that stuff, you can consider having a home automation system featuring voice recognition, voice synthesis, computer vision, internet/RF connectivity at low cost and with low power consumption.

I should receive my Thunder Pack soon…

NXP LPC1758

Playing with microcontrollers is one of my hobbies and I’ve recently bought some new 32bit ARM Cortex-M3 devices to play with.

In fact, I’ve already soldered a few NXP LPC1756/LPC1758 on some 0.5mm LQFP Schmartboards.

But it seems that beginning with those devices is quite hard if you’re not a veteran of ARM prototyping and programming…

So I’ll try to share here my experience in trying to define a complete development system.

And while doing so, I will keep in mind my requirements :

1) defining some cheap microcontroller kits/units.
2) using a free & open source toolchain. No size limitation, commercial use must be allowed.
3) keeping a low investment and complexity for the development tools (low cost JTAG programmer, hand soldering compliant solution…)

Now, my next step will be to make the LPC1756 blink some led !