how everything is connected (for now)

There are currently three different parts:

A "requester" client that will request for a door opening.
A single "target" client (the Raspberry Pi) that will receive requests
A central server that will relay the messages between the "requester" clients and "target" client

The messaging is done using WebSocket--really great stuff.

"Requester" Client
Currently just a simple PHP/JavaScript page that can send a textual message to the central server.

"Target" Client
A Python script that keeps an active WebSocket connection to the central server. As said above, this is executed in the Raspberry Pi.

Central Server
A Python script that listens for WebSocket messages. This uses the Tornado library for Python for creating the WebSocket server. This is executed in the Ubuntu web server.

I'll try to put more details as I go, but for now, I think this 10000-feet view is the better for catching up with the status logging.

Comments

finally got around to it (nrf24l0+ and servo)

On a previous post , I used the nrf24l01+ wireless chip to communicate between the Raspberry Pi and an Arduino, but only got lights to turn on. I remember being confused as to why servos would not work, and somewhat left it there. I started messing around with it again, and I am concluding that it might have been just a power issue. Here is the servo moving properly: The Arduino is on the ground due to the short length of the wires powering them. Just as a recap, what is happening is: - a C++ program using the RF24 library is compiled in the Raspberry Pi (connected to an nrf24l01+ chip) to broadcast a message. When executed, it will broadcast the message. - the Arduino (connected to another nrf24l01+ chip) programmed to receive messages receives the message, and upon receipt sends a signal to an Arduino that is wired to the servo to move the servo. Two separate Arduinos are used, as it seems that the servo library and the RF24 library do not seem to run properly toget...

alcohol sensor (and some patience)

Soldered the alcohol sensor into something that is connectable: I tried to connect this to the Arduino, as I had the appropriate circuitry, but I did not get any legitimate output from it. 5V going in, 5V coming out with no variations. Nothing seems to be awry in wiring, as the circuit seems to be grounded properly (and the 5V current is flowing). There are a couple of potential factors as to why I'm not seeing any results: - I'm using a 10k ohm resistor, while some guides (and the datasheet for the sensor) asks for 100-200k. However, there seems to be a good amount of people using 10k and getting at least some kind of result. A batch of 100k ohm resistors I ordered is on its way, so I guess I can try with them when they come. - This site claims that these sensors take 24-48 hours for its signals to be stable. It also tells me that I should not be powering the sensor directly from the Arduino, which I have been doing, out of concern that the power draw of ...

how the fingers work

the fingers are moved using wires and tension. each finger is looped through with a wire/string/line in a top-bottom fashion. when the top wire is loosened/bottom wire is tightened, the finger curls in its joints, resulting in a "bent finger". you don't have precise control of each joint movement, but it is simple enough to be controlled by a single actuator (in this case a servo). here is me just using my own hands as an actuator: here it is hooked up to as servo and controlled by a potentiometer: the movement is not smooth because 1) it's controlled by a potentiometer that I am controlling, as seen in the background, and I was unable to move it all the way with one smooth finer motion. 2) the tension in the line was not entirely tight. I need to learn how to tie these well. now I have a get a bunch of servos. much credit and thanks to Inmoov once again.

the quest for robots

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