arduino

WiFi Thermal Printer with Arduino

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I have been working on a wireless thermal printer for an application that I have in mind.

The system is composed of the following parts:

The WiFi shield uses the SPI bus, which leaves the serial port free for the printer. In the video below, you can see a simple example of Internet-to-Printer connectivity. As a standalone system with no connection to a PC, the system is started up, and it pings Google. When a successful ping response has been received, it prints the letter “P” with the printer. More information could have been printed here, but since I use an Arduino Diecimila with very little memory, the program only fits on the microcontroller as it is.

  • The Arduino with the TI CC3000 WiFi shield.
  • Thermal Printer + WiFi Shield + Arduino

Here is the code used in the example:

DIY Cellphone, Part 2

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The last couple of days, I have been trying to put my cellphone together. Using soldering paste with lead requires good ventilation. The fumes are poisonous, and you shouldn’t breathe them. That’s why I had a big fan by my side. Your friends are; soldering paste, flux for the hard ones, a soldering iron, a tweezer, and patience.

I discovered that I didn’t receive the correct LiPo charger, and I haven’t been able to power the phone to program and use it. I have contacted the supplier (Electrokit), and I am sure they will find and ship the correct one. Still, I have to wait over the weekend before I can use my phone, which is not fun =(

Here are some pictures from the soldering procedure:

DIY Cellphone, Part 1

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I believe in a society like today, we need to have better control over our communications. Today’s smartphones have been accused of being devices of mass surveillance. Therefore I have decided to build my own cellphone. I found this guide on the internetz, which describes an open-source cellphone platform based on a GSM module and an AVR microcontroller. I selected it as a starting point for my cellphone. It will most certainly receive software updates from me (I want snake!), and probably even hardware updates in the future. Yes, I know, GSM is not secure at all, and it is vulnerable to man-in-the-middle attacks, but I still prefer the man-in-the-middle over nsa-over-the-internetz.

Enough jabber, for now, let’s get to the fun part! So far, I have received all the needed components from the Bill of Materials (BOM) for the phone’s LCD version, besides the PAS414HR-VA5R SuperCap, which has been discontinued. Since the proposed replacement part isn’t good enough, I managed to find some leftover PAS414HR-VG1 at Farnell and instead ordered a few of those. It will take some scratching and soldering to fit it on the PCB, but its values are correct. Since I am living in Sweden, I had to find alternative suppliers for my materials (Electrokit for some electronics, In-Time for the antennas, Farnell for the SuperCaps). Some had to be ordered from DigiKey anyway. Try to keep your parts ordered from DigiKey below your country’s import tax threshold. Otherwise, you might end up paying import taxes like me, which is not fun.

Here is a picture of the PCBs from OSH Park, which are of excellent quality. More will come once I receive the SuperCaps and start soldering the cellphone.

Cellphone PCBs from OSH Park.
Cellphone PCBs from OSH Park.

Master’s Thesis: Improved traffic safety by wireless vehicular communication

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I have recently completed, presented, defended and passed my master’s thesis project. It was a great experience which I believe has the potential of preventing traffic accidents and saving human lives. Bellow you can read the abstract and if you are interested you may download the whole report here:

Abstract

In tomorrow’s vehicle industry vehicles will have the ability to communicate and cooperate with each other in order to avoid collisions and provide useful information to each other. However, for this cooperation to be possible all vehicles will have to be equipped with compatible wireless 802.11p modules that implement the ITS-G5 standard. During the implementation phase of the system, there will be plenty of older vehicles without such equipment.

This thesis addresses this problem by developing the hardware and software for a roadside unit called Drive ITS. It consists of a universal medium-range radar that detects older vehicles, an 802.11p modem that forwards their position and speed vectors to newer vehicles, and an embedded system that utilizes and integrates those two parts.

The hardware for the embedded system is divided into two main parts; a microcontroller board and a single-board microcomputer. The software is written in two programming languages; C++ for the microcontroller and Java for the microcomputer.

Tests have been performed by comparing Drive ITS results to results from other vehicles that already implement the ITS-G5 standard and it has been confirmed that the system works as it was intended to.

This solution will prevent potential accidents of newer ITS-G5 vehicles with older ordinary vehicles thus saving human lives.

Arduino LCD Keypad Shield – Clock Application

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UPDATED: I removed all delay(); calls because they were not accurate enough, and there was a time drift. Instead, now there is a while(); that waits until the required time has passed.

Recently I found here a really cheap LCD shield with buttons for Arduino.

Today it arrived, and I made a simple clock program to test it out. It’s a little slow when refreshing the screen, but it’s perfect for the price.

A really cool application would be to use it together with a Raspberry Pi to execute simple commands and see a small web server’s status.

Here are some pictures, a video, and the code for the clock application. It is using the LCDKeypad C++ class which can be found here.

  • LCD Keypad
  • Arduino and LCD Keypad

WebVisitors blinker

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I already wrote my first Arduino program. It’s really simple but fun :)

What it does is that every time somebody visits my website, a LED light blinks once in my room, and I get a warm feeling of a visitor ;)

How to do that:

  • Burn this code to your Arduino:
  • Connect a LED light to pin 12 and ground it.
  • Connect your Arduino to your web server through USB.
  • Log in to your web server and type: “sudo chmod 666 /dev/ttyUSB0”.
  • Add this PHP code to your website header:
  • Enjoy! :)

In case this doesn’t work; try to solve your problem or comment this article and I will try to help you.

Arduino Diecimila