My dog Penny is one of the best. She has the two critical commands of ‘come’ and ‘stay’ down pat so well that I can go for a run with her off-leash here in Denver. She’s gentile with our newborn baby, and she doesn’t destroy things. Her only issue is that she goes BONKERS for food. My wife and I have done a great job training it out of her when we’re around so we no longer have to worry about a cheese board sitting on the low coffee table, but I know she gets on the counters any time we are away.
I decided that it might be helpful to have a surrogate to defend the counters when she’s home alone. After the success of the Silent Laser Doorbell <link>, I decided that a Laser Dog Watcher could be similarly effective. Here are the features:
Setup a Laser tripwire using the same mechanical system in the Silent Laser Doorbell<link>
On a laser beam break, trigger the digital GPIO of a Raspberry Pi<product link> to play an audio file of me reprimanding her AND taking a photo with the Pi Camera<product link>. The audio file changes so it’s not always the same.
There is a calibration knob to allow for various levels of ambient light.
There is an ‘enable’ switch to disable the audio and photo features to allow the user to line up and calibrate for ambient light.
If the first audio file doesn’t get her off the counter and reestablish the beam, it plays up to two more audio files before disabling itself. That way it won’t loop over and over in case the system was knocked out of alignment,.
A couple years ago, I showed how to setup an ownCloud server on a Raspberry Pi. The system worked, but there were some performance hiccups. Most importantly was the ability for the system to handle large files and for the Pi v1 to take on the task in a speedy manner. I found myself using Microsoft’s OneDrive more often, electing to use their more proven platform for anything that didn’t require tight privacy controls and a firm handle on my data’s location. Still, it was a small, secure, and low-power cloud storage solution.
With the latest release of the Raspberry Pi 2, I thought this was a perfect time to update both my hardware and software in hopes of seeing performance improvements. The result gave ownCloud a whole new lease on life, at least in my lab.
Last week the Rocky Mountain chapter of the Surface Mount Technology Association (SMTA) held their 2015 expo at the United Club of Mile High Stadium (home of the Denver Broncos). The event, which was free to the public, brought together anyone related to the design, procurement, and manufacture of surface mount boards for technical sessions and sponsor exhibits as well as a stadium tour, lunch and happy hour.
They had some amazing sessions on how to optimize an SMT line including a lot on cleaning and I learned a lot. Populating boards is a nuanced task!
I love designing PCBs. It’s more than just connecting wires in a given area; it’s devising clever ways to make connections while controlling the design for things like EMC, switcher noise, signal integrity, heat dissipation, and many more.
But the actual laying down of traces isn’t the whole challenge. The design needs to be accurately described to the manufacturer to be sure that everything comes out correctly. Generating footprints, managing the BOM, noting the placement of each component and its rotation are all integral, if boring and time consuming steps.
I’ve found many useful ULPs (User Language Programs) in EAGLE, one of my CAD packages. These have saved me time and errors, resulting in better schedules and costs for my clients. I’ve shared a few of them in my latest element14.com article:
Sometimes the notion of the Internet of Things (IoT) strikes me as silly; why would anyone want to connect their dishwasher to the internet? But still, I wanted to develop a hobby project that would explore some of the tech.
I came across Xively, a service that can take data from a Raspberry Pi and publish it to the cloud. What’s really nice is that it takes care of the networking, security, and dataflow management. Compare this to the Dog Kennel Project that I made when I got my Pi, and it is much simpler.
Most of the designs that I work on require some sort of power supply design. The power supply rails are the foundation of a good design, allowing one to hit not only the desired voltage level, but also low noise, efficiency, and EMI specifications. There are many tests a power supply design goes through before it can be qualified, however there are a few that are almost always used.
I thought I’d use my Tektronix MDO3104 to show some of the tests that are always done on a switch mode power supply design. I’ve created the video below, and written an accompanying article over at Element14.
Single board computers (SBC) are a great way to run some simple linux or Android software with hardware that is small and low power. Wiring up some peripherals like cameras, sensors, or any other custom electronics is the most common use for these little hardware gems so it makes sense that it should be easy to make nicely designed expansion boards for them.
I just created a few EAGLE libraries that are hosted by Element14 that captures these boards so they can be easy to expand upon, similar to the one I created for common Arduino boards. There is one for each the BeagleBone Black, RIoTboard, and Raspberry Pi Compute module. The libraries are designed for someone to either (a) start a custom board with a schematic symbol and package to represent the SBC or (b) document their project that is skywired into an existing board with just a symbol (by using the ‘EXT’ version, which has no package).
I think the Rpi Compute one will be the most popular. You can drop in a fully functioning linux box the size of DDR2 memory into any design in no time thanks to this library! Just watch out for some of the trace impedance specs as noted on the schematic.
I’ve been thinking about getting a new scope for a while. I currently run on a Tek TDS2024B 200mHz scope. It’s been a fine instrument for the last few years, but with the new mixed domain technology and my more regular use of digital technology, I thought now would be a good time to look at an upgrade.
Of course any equipment purchase needs to take it to the next level; like buying a new boat. So I have been reviewing the new Tek MDO3104 and how useful it is next to my TEK TDS2024B over at element14. Are you thinking about taking the scope plunge like I did?
These last couple of months CJ Gervasi and I have been reviewing the Fluke Connect system on element14.com. It’s a neat system where Fluke is using smartphones and tablets as an additional user interface. Note that they keep the standard user interface with knobs and buttons. But they added BluetoothLE in each of the instruments.
Users can not only read data wirelessly, but run datalogging applications, save measurements to their phone, video conference with colleagues while sharing live data on the screen, and organize recorded data by the job order or equipment.
It’s the first of its kind and I think they have done well out of the gate, even if there are a few bugs.
I’ve had a problem since moving into my new place that I can’t hear people knock at my front door. Sure I could get a doorbell at the hardware store, but those things stink. Instead, I thought I’d create a quick and simple Arduino and XBee based system to do it for me:
Doorbells are the 20th century version of today’s perpetually-interrupting cell phone. There you are, cooking a delicious dinner or reading a nice book when the doorbell rudely goes off in your ear. Sure, you’re glad to see whoever is at the door, but interruptions that chime can be so obnoxious. Needless to say, I do not have a doorbell.
The problem with the knocking system is that I usually can’t hear when someone knocks from my lab. I depend on Penny the Dog to alert me when someone is at the door. Except Penny sleeps most of the day. And then there are the delivery people (UPS/FEDEX) who can’t be bothered to knock, even if it is a next-day-early-AM shipment of parts from element14 that I am eagerly waiting for.
I decided that I’d create a project that solves all of my problems: a silent LED that flashes whenever someone approaches my door. It is based on a laser tripwire and will be able to run day or night, even in the bright Denver sun. And if the blinking LED is annoying, a simple button press disables the alert and resets the trigger.