Raspberry PI Arduino Shield - Cheap Option

I have a project on the go which I call Project Doorman aka Carlton. It will involve a Raspberry PI, I2C connections controlling a 1-Wire controller which will be connected to a DS2408 switch. I will use an iButton ID keyfob and sensor i got from http://www.homechip.com a few years ago. So, keybob, open the door and Bob's your auntie.

I wanted to have as much of the electronics mounted on the RPI. I have a Slice of PI by ciseco.co.uk but the prototyping space is too small.

I was also looking at the Adafruit Prototyping Pi Plate Kit for Raspberry Pi but that would cost €20 landed. I was going use it, so all the fancy connectors etc., would end up not being used. Feck that, I said. I know the bits would be used on other projects. A penny saved is a penny to squander.

I read about a fella who was talking about using an Arduino Prototyping Shield on the RPI. That sparked an idea.

In my previous researching/playing with Arduinos, I got Budget Proto Shield (x3) from Oomlaut.com. I had one I hadn't used.

So I desoldered the headers, and soldered one on the other way.

Presto Chango, I had a Cheapo Raspberry PI Prototyping Shield/Plate

Here is the Protoshield attached.

it only uses a single line header, which provides access to the I2C pins (3 & 5). I also get 3.3V on pin 1. I will also need access to the 5V pin (2) and Ground pin (6). I probably will put a small header piece to accomodate this and solder some pieces of wire and connect it to the Shield. I don't care really, whatever works.

It is a nice size and definately has the real estate I need.

From the side. I used the space to have it fit on top of the other bits of hardware, in this case, the composite video connector. Everything has to be nice, after all.

Kist the header from different angles.

Here we have the major components that will be used for this project. The red guy is a Logic Level Converter I got from CoolComponents.co.uk. Very cheap and useful. It ensures that I only have 3.3V connecting to the RPI.

The next girl is the Dallas DS2482-800 the I2C 8 Channel 1-Wire Master Controller. I used the Tirna SMT SMD DIL adaptor SOIC 16 PIN NARROW  to mount the DS2482-800. Very Handy and fairly cheap.

The final good buddy is a Dallas  DS2408 a 8 Channel 1-Wire Adressable Switch. Very handy. Again I used the Tirna adapter.

That is about it. I will probably reorganise the layout to facilitate adding extra components. I might add a couple of light sensors, while I am at it.

So, what are the benefits? Cheap and Useful. I don't really need a prototyping board. It is going strainght into production.

Raspberry PI Stuff and Building a Case

My Raspberry PI arrived a few weeks ago.

I tried both the Debian and Arch Linux boot images.

I don't have a convenient HDMI TV to play with, so I settled on the Arch version.

It suites me better, as I really wanted to use it as another Plug Computer, to do something with.

What to do with it? I am not sure yet. There will probably be something Home Automation related.

I am a big fan of the 1-Wire technology, for temperature sensors and control, so I compiled the latest version of OWFS on it. It worked fine with the USB 1-Wire controller.

The RPi has an I2C interface, so I decided to get my hands on a couple of  DS2482-100s and DS2482-800s. These are I2C to 1-Wire controllers. After a bit of messing about, I was able to address the conrolllers using OWFS.

That will be a furure post, hopefully.

I was looking for a suitable plastic case fir the new toy. There are quite a few about and rather pricy for what they are. I liked the one on SKPANG. Including postage and VAT, it would come in at about €20.  As my friend Ber would say 'Balzac' to that.

I came accross a post by Pecker Dunne on raspberrypi.org http://www.raspberrypi.org/phpBB3/viewtopic.php?f=40&t=9165&e=0

I was able to get a small sheet of perspex. Using youtube, I was able to determine that the 'score and snap' method was the best and cleanest way to get the pieces I wanted.

I made a few attempts. Two sheets of perspex and some No4 screws and nuts. I got some plastic washers to hold the board. It was just the job.

Attempt 2. In the presious version, I had put the screws too close to the IO header.

I also decided to make a breadboard version of it, to add breadboards and a USB hub.

I found that 3 screws would hold the RPi quite tightly and was easier to position the top piece.

Add a 10 port powered USB Hub

Some Breadboards
 

A Nanode and Xino Basic Arduinos for completeness.

I plan to use the slim breadboard for connections from the RPi headers and the larger one for the various components.

I sized the main plate, based on a plastic box with cover I have. Everything fits in and can be safely stored between project activity.

The next investigation will involve the Ciseco Slice of PI and the XRF radio module.

Remote Control Light Switch

I ordered a single and double light switch from www.carymart.com about 4 weeks ago. I has just arrived.

It is quite a nice product and fairly cheap. The single $24.50, about €16. The double is just a few dollars more.



I installed the single one in the kitchen controlling some florescent lights. The build of the switch is a bit old fashioned looking but it functions perfectly. When installed it looks great.

The remotes are a bit 'Get Smart' looking, with a pull up aerial. Secret agent walkie-talkie.

They work fine.




Hidden screw holes. Street Cred = 100.
One of the things I liked about it is that works with CFL and florescent bulbs.

The only issue I have is that the switch has a toggle operation.

Press the button and it switches on. Press it again and it turns off.

There is no way to know the state of the switch, i.e. if it is on or off.

I would much prefer a switch that I can send a specific 'On' or 'Off' command. That would fit in with my plans for for my Home Automation set-up.

Would I recommend them? Yes.

I will probably get a couple more.

The double switch will probably be installed in the hall to remotely control the lights in the porch and hall. Very handy on a cold wet dark evening, to be able to turn the lights from the car.