json messaging (2/2)

Took a good 2 hours to change all the messages into JSON format and make it work.

But it is done. All is JSON.

Using it like a map, currently with three key-value pairs:

"id" : for entering a session ID of another session if needed. Currently used for the web client to receive a acknowledge response to confirm that the target received the message (mainly for testing purposes).

"type" : probably the most functional data going through all this. Current types are

STARTUP_TYPE - for when the target sends its initial message, the server uses this to mark which session is the target.

REQUEST_TYPE - for when the web client sends a request to the target. Server uses this to send request to target.

ACK_TYPE - for when the target finishes carrying out the requests and sends an acknowledgement of the completion of the request to the server. Server uses this to send confirmation to the web client

MISC_MSG_TYPE - for anything else.

DEBUG_TYPE - currently for the pinging that the Raspberry Pi is sending to the server.

"message" : currently holds messages that are visible in the web client's screen. As the screen would most likely be gone in the end, this and MISC_MSG_TYPE might disappear.

Anyways, code got cleaner once every message was converted to JSON (no more regex blobs), but it's still messy in some parts.

Comments

duty cycle testing

Now that I saw a physical response, I should try to make it similar to how a servo should be controlled. Servos are actuators that receive (expect) position input (as opposed to motors, which receive speed/intensity input). Simply put, it registers input as pulses, decoding the ratio of high (a "on" signal) to low in a given period as a position value. A better explanation : http://learn.adafruit.com/adafruits-raspberry-pi-lesson-8-using-a-servo-motor/servo-motors As I am waiting for my servo to be shipped, I will continue to work with the LED light. As opposed to my previous setup of having the light turn on every time the request is given, I will have the light turn on and off in a regular pattern until a request is given, upon which the pattern will change for one "cycle" (on-and-off pair). The on-and-off logic (previously the LED control logic) will be run in a separate thread: def dCycle(*args): global dCVal ...

dabbling with android

I've been wanting to dabble with Android development recently, and yesterday I realized that there is a Socket.IO client API available for Java/Android. The API is pretty straightforward, so I loaded a test Android project I had made for going through Android basics and connected to the OpenSesame Node server. and it works! I mean, the interface is non-existent and it's really just bare-bones, but having the servo respond through an Android application was pretty refreshing. (the web client and the android client "communicating" with each other--messaging is pretty much for debugging purposes)

playing with servos

some servos that I had ordered were delivered. the instructions suggested another brand/model of servos, but these were a much more economical (cheap). I tried adding them to the hand: I'll have to print the "pulley" pieces that will be attached to the servos. meanwhile, I did somewhat (hackily) got the wrist to work, for now: you keep hearing the "usb plugged out" sound in the background, and that's because the servo was being powered by the arduino. the servo's power draw appears to be causing a shutdown of the device. will need a better power source for the servos. it feels like these pieces that are supposed to be plugged into the servo will have size issues.

the quest for robots

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