He may not look like much right now, but STEVE is an evolving project I’ve been wanting to start for quite some time. He is a robot, into which I will combine software, hardware, and mechanical design.
Currently STEVE is an AVR microcontroller and LM298 dual motor driver, strapped to a circa 1985 remote control car. Over the last few days, I began laying the foundation with serial communication, motor control, and power. In the next few weeks, I should receive the first order of parts to give STEVE senses.
- Ultrasonic range sensor
- 9-Degrees-of-freedom Intertial Measurement Unit (with compass)
- DS18B20 Temperature Sensor
- USB WiFi Adapter
- LM298 Motor Driver (a better unit)
- Servo (to pivot ultrasonic range sensor)
- Current Sensing
This is a great wish list, but without the software to tie it all together, not very useful. Therefore, I’m assigning my Raspberry Pi 2 B+ as STEVE’s brain. My vision is for the Pi to do all the heavy processing such as navigating, making decisions, and hosting the user interface for mission planning. That way, the AVR is only a hardware controller that manages Input/Output, and communicates bi-directionally with the Pi.
Over the last week the project has evolved very rapidly, and a new body is in the works. My 3D printer has some serious overtime coming up, as I begin designing and printing STEVE’s mechanical components. The ability to print new wheels, mounts, gears and body components is critical to the success of this project, and will also mean I can be very flexible with how everything is implemented.
I have a lot of freedom to do really cool things with this, and I look forward to posting regular updates on STEVE’s progress here!
The other day, my Denon AVR-1801 home theater receiver stopped working. It would power on, reach the point where it normally enabled the speaker outputs, but then it would shut off. The status LED would rapidly blink on and off.
The user manual suggested that the device was overheating, or that the speaker terminals were being shorted. The device was not hot, as it was just turned on. I unplugged all input and output cables, but that didn’t fix it either. Time to dig deeper.
A quick Google search revealed the following gem. There are four “surge” resistors in line with the ±15 VDC regulators: R141, 142, 148, 149. These 1 Ohm resistors weaken over time with every power-on surge, and the resistors from the factory were not strong enough. Armed with this knowledge, I opened my receiver to test these resistors.
The majority of external hard drives are nothing more than a case, a USB-SATA adapter, and a standard 3.5″ or 2.5″ hard drive. Despite having this extra hardware, they sometimes actually cost less than their bare counterparts. Why might this be? External drives usually only carry a 1 year warranty, while the average desktop drive today might get 2 years of coverage.
Above is a 3TB Seagate Expansion external hard drive. It has a USB 3.0 interface, and accepts 12VDC for power. I bought this a few years ago for $10 less than a bare 3TB SATA desktop drive.
Western Digital released a line of external hard drives where, when you take it apart, you don’t find a normal drive inside. Instead, the control board is actually a USB interface, not SATA.
Out of curiosity, and because I might put this drive inside my server in the future, I decided to tear it apart to see what I was working with.
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!
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.
This project was completed about a year ago, and I’m surprised I never posted it before!
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!
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!”
Bally’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.
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!
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?
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.
Breaking the 64MB, chinese-made promotional USB key was not the disaster – it was losing the files on it.
I’ve had luck before re-soldering damaged USB key connectors, so I got my tools together and gave it a shot.
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.
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.
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.