I just implemented a very simple example of serial communication in circle. I used a handshaking algorithm that works with two arduinos. I just added the same algorithm to the third one, plugged them properly, and it worked! The result is that it makes all of the modules synchronize together.
The handshaking algorithm is very simple. Each node has one sender and one receiver. The board sends a "ping" signal to its receiver. It then waits for a "pong" signal to come back from its sender. Since each node does the same thing, the objects will eventually synchronize as the messages propagate.
Alors, suite à mes dernières expériences et constatations, voici un petit résumé de la situation actuelle. Quand j'ai commencé à réfléchir à cette idée de réseaux de modules sur laquelle je suis parti, j'avais en tête un réseau avec des connections un peu dans tous les sens. Les découvertes que j'ai faites sur les protocoles sériel et I2C me conduisent à la conclusion qu'aucun de ces deux protocoles ne permet, a priori, ce type de réseau. Cependant, ils permettent d'autres types de réseaux.
I had a late night reflexion about I2C communication with more than 2 devices in a multi-master network. I made a videocast that explains the whole idea. However, my first real-life experiments has raised important synchronization issues with respect to I2C communication in multi-master networks.
Super LEDs suggested by Meriol. Low voltage (3.2V), low amperage (20mA) and incredible luminous intensity (80000-100000mcd).
I had this (wrong) idea that I could communicate with more than two Arduinos through the RX/TX ports using Serial communication. One of the issues is, (1) that it's not possible to do so :) ... and (2) even if it would, it would not be possible to identify the nodes in the network. Chatting on the Arduino IRC channel, I was suggested to use a protocol such as I2C or 1-Wire.
J'ai discuté avec Meriol aujourd'hui de la question de la connection et des fils pour relier les modules dans le projet Entangled. La problématique est la suivante:
I always wonder, so I write it down here as a reminder. To the question: can we plug 12V in an Arduino? The answer is: yes, between 6 and 12V. Reference here. Quote: "To power the board from an external power supply (6-12V), place the jumper on the two pins closest to the power plug."
This is a first idea of interest to me for an installation in Thailand. I'm thinking of a wired network of objets to be placed in trees. The objects would all be linked together in a strong network. Because of natural conditions such as weather, branches falling, trees growing, some of the links will break. The objects should have the ability to nonetheless transmit the information.
I have this idea that maybe we should be able to "see" the signals passing from one node to the other. However to be interesting we would thus need to have lots of nodes, which might be a problem.
Bon c'est un peu un prétexte pour essayer ma nouvelle bébelle mais c'est surtout que cette sortie impromptue m'a surprise. Simon, un ami qui m'héberge à Québec, nous a montré son animal de compagnie après le repas, pendant le café hier soir. L'animal en question aime bien la pénombre et se nourrit de crottes et de pourriture. Sympathique!
I arrived this morning at Avatar with the first Montreal-Quebec bus. I used for the first time my brand new iPod Nano between the metropolis and the capital; headphones on ears, I slept a little to the sound of the voice of Vashti Bunyan.
I unpacked my electronics material, although I have not had time to start today. I have to get started on this project, I'm still too far from it now. One thing at a time: first I need to set up this website. It's now almost done ...