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Ahh! What a fine day, for SCIENCE!

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Hello there, journal, long time no see.

As always, I've been busy. Currently doing full time job, running four projects alongside, studying bioinformatics and raising a kid biggrin.png

After re-watching Dexter's Laboratory, I felt urge to go back to electronics for a bit. I may not have lab hidden behind bookshelf, but I could do SOMETHING, right? Obviously, after not touching electronics in ages, I barely recalled what's what. First job, as usual, was to make an LED light up. Then I've adde a button that would make the LED light up only when pressed. And then I went into the think tank.

Ever since I was a kid, growing up watching movies, shows and reading books about AI, malicious or otherwise, I was fascinated by it. One of my first projects ever was to write AI in BASIC. Obviously, I was just a kid, and had no idea what I was doing, but seeing 'HELLO, MANTIS' on my old, amber monitor made me really proud. I wanted to create a virtual buddy, a computer which would be my assistant as we discover things for SCIENCE!.

So, what is my project? I want to connect my virtual creations, with reality. The start will be creating camera on a remotely controlled arm. Camera shall be processing images and, depending on software I write, react to them in certain ways. Hell, maybe it'll just HELLO, . That would be nice evolution of what I started all those years ago.

How do I go on with this project? I'll be using Arduino UNO for prototyping, but later I'll probably just etch my own one. My awesome creation will look sort of like this (who needs CAD when you have Paint?):

There will be three to five servos: One to rotate the base, one to angle the base arm, one to angle second arm (second arm is optional), one to rotate camera so that it's level no matter the angle of base arm, and one to rotate the camera around the forward axis - its roll (optional as well). That's the positioning platform. There will be camera attached to the arm, that'll be connected to a processing computer (most likely some kind of rasPi). Computer will recognise the data, and send servo positions to the Arduino.

But how do I send the data? At first, I thought about using nLF24L01 wireless modules to connect between computer and the robot. But that required to create my own wireless dongle to connect to the PC. So I decided to go with WiFi. It would be good to have possibility to connect everything in the lab in a network. But first, I wanted to check out another way of controlling it - via bluetooth. First, I needed to learn how to communicate with bluetooth.

So, first subproject: turn an LED on and off remotely. I have connected HC-05 module to Arduino. The code on the remote side was simple:#include SoftwareSerial bluetoothSerial(10, 11);bool ledState = false;void setup() { // serials Serial.begin(9600); bluetoothSerial.begin(9600); // ledpin pinMode(13, OUTPUT); setLEDState();}void loop() { int c = bluetoothSerial.read(); if (c == 0) { ledState = !ledState; setLEDState(); }}void setLEDState() { if (ledState) { digitalWrite(13, HIGH); } else { digitalWrite(13, LOW); } Serial.println("State switched");}
However, code on the server side gave me troubles. At first, I had to choose the platform I'd be using to control my robot from. Since I was using Bluetooth, at first I thought about creating app for iOS, alas, even though my laptop was detecting the bluetooth module, the iPhone didn't. It turns out that HC-05 is SPP Bluetooth, and iPhone only connects to BLE bluetooth signals. Which means that I was going to need to write software for OS X.

I've decided that it was a good time to polish my Swift skills in a real world project. Using IOBluetooth framework, I've written a simple communications tool. Well, by 'simple', I mean 'it took me wayyy longer than I expected'. I have some problems with interoperability with Objective-C methods, especially with UnsafeMutablePointer<> area, but eventually I've figured it out. So, currently I'm sending an integer from my control project via bluetooth, and when the Arduino receives that integer, it switches the state of LED on pin 13.

Here's a picture of assembled, working circuit:


What's my next goal? Well, I want to have at least couple servos. At first I wanted just to send tuples of [servoID,servoPosition], but then I thought that I may want to add some other things (HD44780 LCD, maybe some LEDs to indicate resonses in real life) to the robot. That would require protocol that is bit more complex, if I want to keep it upgradeable. So, I'll be working on to Arduino that controls couple LEDs, data that controls how long each led should blink. That would basically be the tuple solution. If/when I'll get that working, I'll try sending more data alongside.

See you around!
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Cool stuff!


I toyed a bit with the Parallax stamp module, the way you handle it looks very similar, although a bit different :)

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