electronics

Homebrew Stereo Gainclone Amplifier

LM3886T/NOPB

LM3886T 68W Audio Amplifier (Newark)

In 2012, one of my posts were featured on Hackaday, a globally read and frequently updated aggregator of projects that modify, create, and otherwise hack. The traffic this garnered was enough to throw a couple 500 Server errors, but it also resulted in getting the attention of someone at Farnell/Newark.

I was contacted through the comments by a member of the Farnell team, who spent quite some time on my site and was “loving the content”. After further communications, he asked if I would be interested in reviewing products for them. Of course I said yes!

The question was, what would I review? After looking through some of their enormous catalog, I realized I’d rather create something out of the components I reviewed, and discovered the LM3886, a relatively inexpensive 68-watt audio amplifier. This is where the adventure began!

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Wednesday, April 9th, 2014 electronics, projects No Comments

Hacking a Laptop Battery – Increase Runtime

Do you have an old laptop whose battery struggles to reach 30 minutes? I used to.

An aftermarket 6-cell pack would have cost me around $40, which isn’t expensive, but the laptop was old (circa 2006) and not worth putting money into.  I happened to have a fair number of Lithium-Ion battery cells “lying around”, and decided to upgrade my pack, not just with new cells, but with more cells.

IMAG0680

This project was completed about a year ago, and I’m surprised I never posted it before!

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Wednesday, January 22nd, 2014 computers, electronics, projects No Comments

Repairing a Projector with Tinted and Washed-Out Display

My employer came to me with a little project. The office projector stopped working properly after someone touched the pins of the VGA video cable, and presumably released ESD energy into the projector. The picture’s colours were all tinted and washed out!

Before

Note that the bottom monitor is displaying the same colour pattern
as the projector. Grey is completely missing!

He asked me if I’d like to take a look at it. My answer, as would be expected, was “of course!”

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Sunday, February 24th, 2013 electronics, projects, work No Comments

Adding Magnet Feature to a Bally Centaur

Hold SpotBally’s Centaur pinball machine came from the factory with an electromagnet, installed in the top-right corner of the playfield. It would hold the ball in place after it hit the “release” target, which initiates the multi-ball mode.

Unfortunately, as time passed and these electromagnets burnt out, it became more difficult and expensive to find a replacement magnet. Most games no longer have the magnet installed, as it was likely removed to be sold.

On our machine, we had no idea if the magnet was still there, and one day decided to look under the playfield to see if there was one. It turns out there was, but it didn’t work.

Magnet Close

After verifying the electrical side was fine, we took out the magnet to find that a screw had gone through the playfield, and through the coil!

Screw Through Playfield       Original

The price of a replacement electromagnet is upwards of $100! Thus, we decided we would remove the old coil wire and wrap our own. After all, how hard could it be?

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Saturday, January 26th, 2013 electronics, pinball, projects 2 Comments

USB Stick Data Recovery

It isn’t the first time, and it probably won’t be the last. Today I had a client e-mail me in some panic, as her USB memory drive had stopped working. It was plugged into the computer, and someone walked into it, bending the connector.

Initial

Breaking the 64MB, chinese-made promotional USB key was not the disaster – it was losing the files on it.

Workstation

I’ve had luck before re-soldering damaged USB key connectors, so I got my tools together and gave it a shot.

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Thursday, January 17th, 2013 electronics, work No Comments

Custom Car Bluetooth Receiver

Currently my phone is simply connected to my radio’s AUX input with a cable, and if I want to change songs I must do so from the phone. Modern raidos have integrated Bluetooth capabilities, allowing you to pair your radio to your phone wirelessly. In some cases, pausing and skipping tracks can be done directly from the radio’s buttons – safer than waking up and unlocking your phone to change songs within the music player app.

jvcradio

I could have purchased such a radio, but I already had a perfectly fine JVC unit I installed not even two years ago. It has two AUX inputs, the one in the front I’ve been using, and a special Bluetooth AUX input in the rear. Although designed for use with a JVC accessory, I decided to build my own Bluetooth receiver for my car.

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Friday, December 21st, 2012 car, electronics, projects No Comments

Quick Flip Fix

After a weekend at the Ottawa Pinball and Gameroom Show ’12, I came home to find that one of my Flip HD video cameras had stopped powering on. It functioned without problem when connected to the computer to copy the videos from it, but it would not turn on to record.

Today, I finally decided to open it up and figure out the cause. I suspected perhaps the power switch was bad, since it didn’t seem to be a major system failure. When I opened it up, the problem was as clear as day:

As you can see, something isn’t sitting quite right. One of the diodes became un-soldered, perhaps due to a shock, causing an already cracked solder joint to completely give up.

Simple enough to fix, a quick test with a multimeter, two points of solder, and everything was back to normal.

You never know if a task will be easy or difficult without first taking a look.

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Thursday, October 18th, 2012 electronics, projects, video No Comments

Modifying a Flip Video UltraHD to Add Charging Capabilities

The Cisco Flip Video UltraHD is a very basic 720p video recording device. It has a screen, a few buttons, and USB and HDMI ports. Not very much going on. Record, play back, copy to computer. However, these devices were discontinued, so my friend and I bought two to share at $29 a piece. I was very keen on using them together for 3D video.

To prepare for this weekend’s 2nd annual Ottawa Pinball Expo, I was making sure all my camera gear’s batteries were charged. The Flip UltraHD takes 2 AA batteries, which is generally enough to allow you to completely fill the camera’s 1 hour internal memory.

I noticed that there was a rechargeable battery pack you could buy for the Flips. It charges when the camera is plugged in to a USB port. This battery pack is really just two AA NiMH rechargeable batteries wrapped together, with a little tab that pushes on a switch to tell the camera that the pack is installed, and not regular AAs. When I realized this, I figured I could modify the Flips to work with my own AA NiMHs, and charge when connected to my computer.

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Friday, September 7th, 2012 electronics, projects 4 Comments

Refurbishing a Brother DCP-120C Inkjet Printer

About a month ago my neighbour gave me an old Brother DCP-120C printer/scanner. The auto-document feeder was what caught my eye at first, but after I looked more closely, the type of ink cartridges it used made me very happy with this gift: they are simply little tanks of ink, with no head, meaning they are very easy to refill and should last a long time. What’s more, it only cost $7 for a full set at 123inkcartridges.ca.

However, after ordering the new cartridges and trying to print, I encountered some problems: nothing came out, except for trace amounts of colour – no black, and it certainly was not printing properly.

This is the inherent design flaw of these printers: they have a fixed print head, that is part of the printer. Unlike HPs and Canons (to name a few), the print head isn’t part of the cartridge. This means that if the printer is left sitting for long, and the ink clogs the head, the whole thing needs to be disassembled and either cleaned, or the head replaced.

Print head on an HP cartridge – replaced whenever you
buy a new cartridge.

Being the do-it-yourselfer I am, I decided I would tackle the task of refurbishing this printer.

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Tuesday, July 10th, 2012 electronics, projects 2 Comments

Final Project – Final Writeup

After yesterday’s exam, I have completed the Electronic Technologies program at Heritage College! Although final marks are not yet posted, graduation is certain, and I can pretty much call myself a Technologist (except not officially).

The biggest part of this third and final year was the final project. I’ve made a few posts in the past about it (video, menu, schematics), and the original plan was to make separate blog posts for each step of the process. However, time constraints, and the sheer volume of material, makes it easier if I just provide this summative post.

This post will be divided down into two main sections: hardware and software. I will try to explain with detail while keeping it short, and cover some of the key elements and choices involved in making this project.

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