Oscilloscopes are a powerful utility for any workbench, but they're one of those tools that you really have to want, and have enough use for. They're bulky and costly, and can be difficult to justify for a maker workbench - think of all the microcontrollers you could buy instead!
But their utility cannot be disputed. We even wrote an entire article about tracing serial and various waveforms using an oscilloscope. It's often the only way to demystify a problematic sensor (or one without a useful datasheet), and allows us to "lift the hood" on what's going on when something's not quite working properly.
We recently had the opportunity to review Labrador - not the woofing kind, but a serious tool for all but the most well-heeled makers. Labrador is supplied as a complete working unit, however it’s totally open source and open hardware!
Another crowd-funding success story, developed by Chris Esposito at Espotek. The product received backing from almost 900 people, raising over $23,000 to bring it to life.
Now you can get your hands on a Labrador yourself!
So what’s a Labrador?
It’s a small PCB about 5cm x 4cm packed with a 2-channel oscilloscope, a 2-channel signal generator, a variable output voltage power supply, a 2-channel logic analyser, and 4-logic level pins. The Labrador connects to a host computer via USB, and that host computer could be a PC running Windows, a Mac, a Linux box, a Raspberry Pi, or even an Android mobile phone.
DRIVING LABRADOR
Before we get to the facilities provided, let’s first take a look at the user interface. Instead of physical knobs and switches, a lot of the functionality is designed around the keyboard and mouse (or trackpad). You can use the mouse wheel to change the display of the oscilloscope, or the frequency of the signal generator output for instance. We found it quite easy to get about.
Oscilloscope
This is a software implementation of an oscilloscope. While the display waveform is a bit jaggy it is very useful and very full featured. The pause function provides a storage capability, which can be extremely useful when examining a complex waveform. The triggering facility is excellent. Best of all, this is a two-channel oscilloscope, which allows you to view and compare two different waveforms.
Function generator
Again, this is software-driven so has some jaggies (this is a result of resolution - it's a trade off, but one that is easy to justify).
There are two separate function generator channels which means you can have two completely separate waveforms at the same time. You can have a sine, square, sawtooth or triangular wave. All of these have variable frequency and amplitude, as well as a settable DC offset if you need that. The maximum frequency varies by waveform, but is upwards of 30kHz for sine wave and 125kHz for square wave.
Adjustable power supply
Labrador provides a variable power supply that can provide 4.5V to 12V in 50mV increments. A very handy feature is that if you change the voltage output but then don’t change it again, in around two seconds the output becomes “locked”, which requires a click on the lock to change the voltage further. This could well save your electronics from losing their internal smoke. It’s worth noting that with a maximum power of 0.75W, this is a reference supply, and not a lot more - but still very useful.
Digital output pins
This is a rather novel facility. There are four pins that you can set high or low, which makes it quite useful when experimenting. If you're unsure that your microcontroller is performing the logic functions you've set, you can easily test this theory but manually triggering them with Labrador and watching the results.
Logic Analyser
An intriguing part of this is that it can examine serial data streams. That could be a real blessing while developing serial data transfer protocols and debugging.
Support
As this is a software-controlled device, new functionality can be easily added. We asked some questions at Espotek and received prompt responses. It’s also open source, so you can easily adapt the software for your own purposes too. This opens up the opportunity for a savvy coder to explore the far reaches of what the hardware can do!
Conclusion
There’s a lot of good functionality in a tiny package here. It is perfectly suited to someone who has infrequent use for an oscilloscope, or would like one they can easily keep with them in the field. While there are some limitations, for a tiny, low-cost unit, that’s expected, and it really out-performs what you’d expect. Now there’s no reason to NOT have an oscilloscope, a function generator, and other very useful tools at your fingertips.
Labrador Board available at ESPOTEK: http://espotek.com/
- Labrador Board $29 USD (Including free shipping worldwide)