Showing posts with label Electronics. Show all posts
Showing posts with label Electronics. Show all posts
Hi! As I mentioned in my latest post on how to make Tiny Encoders for DC Motors, some time ago I went to a junkyard to salvage two powerful high torque DC motors from car window lifting systems to use in a robot. I had to take my own tools and dismantle the doors from an old Renault Laguna myself  to get the motors and then managed to negotiate with the seller to buy both motors for 25€, which I think was quite cheap.

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Tiny Encoders for DC motors

Hi again! Today I'll show you a small part of a project that I did a long time ago and, due to some changes of plans I didn't end up using. Anyway, maybe this small project might come up handy for you.
Some time ago I went to a junkyard to salvage two powerful high torque DC motors from car window lifting systems to use in a robot and had to make some encoders to put in them. The space where I could put them was really small so I had to find really small sensors and design a PCB for them in Kicad.
The sensors that I used were Vishay's TCUT1300 IR Transmissive Sensor with photo-transistor output. Following the sensor's datasheet I designed a small board (10x8mm) that would fit in the space that I had available.

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CNC Controller Board v2

As I said previously, I have been slowly developing my second CNC Machine, TheMaker2. To control the new CNC machine I developed a new board based on a PIC16LF877A since the L297's that I used on the first CNC controller board that I designed can be quite expensive here in Portugal and I had some PIC16LF877A samples lying around that with a few programming lines could do the same or even more than three L297 stepper motor controllers.

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Once again, the board design can be split in three parts:
  1. Isolation - it has Vishay's CNY17-2 optocouplers to isolate the parallel port from the rest of the circuit;
  2. Driver - a Microchips' PIC16LF877A drives three stepper motors in unipolar mode (if you prefer bipolar you can change the schematics and boards at your will);
  3. Power Interface - a bunch of Vishay's SUP85N03 N channel FETs working as switches controlled by the PIC16LF877A.

Homemade CNC: TheMaker2

Hi! As I previously said in my first post about my first Homemade CNC: TheMaker1, I was slowly developing a bigger, faster (didn't accomplish this part yet) and more robust CNC. Well, the development phase has finally come to an end and it is finally ready! :D In order to build a more rigid structure I decided not to build it with a moving gantry, but with a moving table on x axis and a fixed structure for y axis, which holds z axis. The build is based on this one.

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One of the main objectives was to make it low cost and believe it or not, with some scavenging involved I managed to build the whole structure with only 84.4€! :D Oh, and this cost still includes some spare materials! :P

Adding an external power supply to a cheap USB hub

Hi again! In this post I'm going to show you how to add an external power supply to a cheap USB hub. :)

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I've been running some experiments with two Logitech Quickcam for Notebooks Pro and the Raspberry Pi and unfortunately I haven't been getting any good results. I can't get many fps and some of the captured frames contain corrupted data but I think I may have found out the reason for that. After some reading I verified that the USB ports of the Raspberry Pi can only source 100mA to a device and maybe the cameras are consuming more than that. To bypass that problem I went out to buy a USB hub with external power supply.

Inexpensive CD Wallet Electronics Tool Kit

Hi! Maybe you're an electronics student, maybe you're an electronics hobbyist, maybe you just had the misfortune of being reading this blog and finding this post :P Anyway, you might find it useful. I'm going to describe how to make an inexpensive (20€), small and portable tool kit with the essential tools for some electronics experimenting or some practical lectures at the university's labs.

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First Impressions on the Raspberry Pi

Hi again! A few days ago I made a post about the Raspberry Pi board that I recently got in the mail. I only made a short description of the board since I hadn't test it at the time. I still haven't much to say but I have finally tested it and I'll share my first impressions of the board.

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Fixing Digital Calipers

Hi there! In this post I'm going to show you how to fix a digital caliper in a very easy way. In fact, it's so easy that I had serious doubts about it until I tried and saw the results with my own eyes. :P

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Using Piklab with Tiny PIC Bootloader


Piklab already has programming interfaces for various programmers, including the Tiny Bootloader. To configure it you must go to "Settings > Configure Programmers... > Tiny Bootloader" and then set your serial port and it's specific settings. In my case, since I use a USB <->Serial TTL Cable (see my previous post on how to make a Low Cost (1,85€) USB to RS232 LVTTL Serial Cable), I configure it with the following data:
  • Port Selection: /dev/ttyUSB0
  • Specific > Port Speed: 19200
  • Specific > Timeout: 300
  • Specific > No of Retries: 5
Get the flash player here: http://www.adobe.com/flashplayer

After inserting all the correct configurations for your serial connection, Click "Apply" and you're ready to go. To program you just have to go to "Programmer > Program". Do not forget to click the Reset button of your development board to reset the PIC and initiate bootloader when you want to program it.

Easy, right? Yes, but it doesn't always work. :( I had it working when I used Ubuntu 11.04 Natty Narwhal and some version of Piklab that I can't remember now but since I upgraded to Oneiric Ocelot and a new version of Piklab, the Tiny Bootloader programming interface stopped working. However, there is another easy way to use Tiny Bootloader with Piklab.

CNC Controller Board

In this post I'll make a short description of the CNC controller boards that I'm making available for you to download and use to control your own CNC. I'm posting 3 version of the same board, but only the first one has been really tested and has been working inside my CNC Control Box for a long time now (see my previous post Homemade CNC:TheMaker1). I'm 99% sure that the other boards will work too because they only have minor changes. I'll explain them to you in a few moments.

All the boards are made in Kicad. The design of the boards is based on the CNC3AX designs, but it uses other components that I had available at the moment that I made the board for my CNC. I advise you that I just wanted to get my CNC running, so I didn't make any careful selection of the most appropriate components and I didn't make the math to calculate the best values for the resistors. I just made it with the components that I had laying around. The boards design can be split in three parts:
  1. Isolation - it has Vishay's 6N137 optocouplers to isolate the parallel port from the rest of the circuit;
  2. Drivers - the ST Microelectronics' L297 drive the motors in unipolar mode (if you prefer bipolar you can change the schematics and boards at your will);
  3. Power Interface - a bunch of Vishay's IRL510 N-channel FETs working as switches controlled by the L297 Drivers.

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Hi! In the following lines I'll present a project that has taken a very long time to complete: my homemade CNC machine. From the first tests and tryouts with various materials to the actual machine 2 years have passed. More important stuff always made me delay the development of the CNC. However, I estimate that the total amount of time was 3 weeks. I think CNCs are a big challenge for anyone since it involves a lot of mechanical, electronics and computer engineering (although we can bypass the computer engineering part by using available software). It was a challenge for me, with lots of frustration along the way because of my lack of skill to make the parts with the few tools I had, but now I can happily say "Mission Accomplished!":D.

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Project Aurora

Hi! Once again some time has passed since my last post. I'd like to post more often but I've been having some busy days. This time I'm writing about a project I developed mostly with my friends and colleagues Gonçalo Pereira and Fábio Martins. The project was slowly developed from December of 2010 to May of 2011 for the event XXVI Semana Académica (26th Academical Week) of the University of the Algarve. The event consists in a full week of partying, with concerts from known portguguese and few international bands. Each course of the university gets a 3x3m tent to sell drinks and raise some money for trips or other purposes. For the Electrical and Electronics Engineering course that we were representing, we decided to make something that had never been done before in that event, something that people are not even used to see in typical bars and discos. Below you can see a video that we made about it, spoken in portuguese but with subtitles in english :).

Low Cost (1,85€) USB to RS232 LVTTL Serial Cable

Hi there! Have you ever needed a USB to RS232 converter to connect to your microcontroller for serial communications? If you have, you probably bought a USB to RS232 converter and then used an external MAX232/DS232 to convert the RS232 voltage levels to TTL levels. That requires a little money, and a little work too. However, there is a simple cable that converts USB to RS232 with LVTTL levels (fully compatible with TTL). Basically you just need to change the connector. The last one I made cost me only 1,85€ with shipping included! :D If you only buy an FTDI chip it will cost you almost the double! (yes, I know that FTDI chips are probably the best USB to RS232 converters but most users don't take require the full features and specifications of an FTDI chip).

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My home Lab

Hi! This time I'll show you my home Lab which is where I usually tear things apart and sometimes make some electronic or electromechanical devices. So, my lab is composed by two workbenches: one for computer programming and electronics and another one for the hard work (cutting, drilling, hammering, etc.).

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How to scavenge electronic parts quickly and safely

Hi again! If you are like me, sometimes you take electronic devices home just to tear them apart and scavenge some electronic components or some dc/stepper motors. It's always a great way to learn about electronics and to save some money. Sometimes you get to know some new IC... sometimes you get some really expensive IC... sometimes you get an IC that you couldn't even buy if you wanted just one or two... So, my advice for you if you like to make some circuits for fun is to start scavenging all the electronic devices that your friends and family throw away.
Until today I always desoldered the components with a desoldering iron and a desoldering pump but that's really slow, really tiring and sometimes it's also very annoying when you want to remove some component that just won't come out of the board or gets its legs ripped apart after 5 minutes of heating, pushing and pulling. Removing conectors or ICs with lots of pins is always very hard too. And the worst part.. it's not good for your health since it releases lots of dangerous fumes. But now I use a new technique! :D

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Hi! This time I'm writing to talk about a great organizer for electronic components that I found, zParts. Some days ago I decided it was time to organize the lots of electronic components that I have in my home lab. I thought about developing an application were I could insert the parts references, the amount of each component I had, and also with some button to open the datasheet without having to browse the folder with lots and lots of datasheets. However, before developing the application I decided to search if no one had done that work before and I found zParts, by Jon Ziebell. I gave it a try, and that's exactly what I needed. It is written in Java, so it works in whatever operating system you have.

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It's very simple to use and allows you to create categories of components, subcategories, and components with as many fields as you desire. You can also relate each component to an image and a datasheet. What else do you need? :D In my case I don't remember anything else I would need, but if you do, you can always program it yourself, since it is an open source project and its source is available in sourceforge. If you need to organize your components, give it a try! To run it just open a console, enter the folder where you extracted the zParts files and enter the following command
java -jar zParts.jar
If you have tested it, liked it and want to add a shortcut for zParts in Unity in Ubuntu 11.10 just do the following steps:
  1. Create a file under /usr/share/applications named zparts.desktop and paste the following code into it 
    [Desktop Entry]
    Version=1.0
    Type=Application
    Terminal=false
    Icon[en_GB]=/usr/share/icons/hicolor/scalable/apps/gdu-category-multipath.svg
    Name[en_GB]=zParts
    Exec=/<path to folder where you have zparts>/zparts_start.sh
    Name=zParts
    Icon=/usr/share/icons/hicolor/scalable/apps/gdu-category-multipath.svg
    NOTE: Don't forget to put the correct path in the 'Exec' line. You can also change the Icon line with the path to the icon that you prefer.
  2. Go to the folder where you have zParts and create a file named .zparts_start.sh and paste the following script into it 
    !/bin/bash
    cd <path to your zparts folder>
    java -jar zParts.jar
    NOTE: Don't forget to put the correct path in the second line.
  3. Give the script permissions to be executed
    chmod +x .zparts_start.sh
    And that's it! Now when you open the Unity board and type zParts its shortcut will appear.
If you use M$ Window$ you can also try out Component Organizer, which is a similar free software developed by a portuguese guy (user msr @ the portuguese robotics forum Lusorobotica. You can check the entire thread about it here).



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Hi! In this blog entry I'll show you how to setup a development environment to develop and compile code for Microchip's PIC microcontrollers. We'll need three main packages:
  1. gputils - a collection of tools for the Microchip (TM) PIC microcontrollers. It includes gpasm, gplink and gplib.
  2. sdcc - small device C compiler
  3. piklab - an integrated development environment (IDE) for applications based on Microchip PIC and dsPIC microcontrollers similar to the MPLAB environment. It integrates with several compiler and assembler toolchains. It supports the most common programmers (serial, parallel, ICD2, Pickit2, Picstart+), the ICD2 debugger, and several bootloaders (Tiny, Pickit2 and Picdem).

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