Reviewed by Bob Monroe
2 June 2015
There is an old business motto that says “If you can’t measure it, you can’t manage it.” Of course this is baloney because intangibles like your reputation, trust, credibility and validity are manageable in almost all forms. Most of those qualities you should manage or else find a new job as a politician. An oscilloscope is a measurement tool, sort of like a multimeter or voltmeter on steroids. This sky blue pen oscilloscope measures current, amps, and voltage as well as sampling rates of 100 milliseconds. The timing rate isn’t huge but it’s certainly good enough for most diagnostics and troubleshooting procedures. To obtain this timing rate, you must use the particular USB cable that comes with the device. That USB cable is a bit thick but is designed for these oscilloscope specifications.
The device is boxed up quite well but I had a heck of a time locating the installation CD. There isn’t one. Instead Sain Smart provides a USB thumb drive with all the necessary files and documentation. Even the most expensive computers don’t come with this great tool. I was impressed at this idea of forgoing the CD or having the new owner downloading the software from a site. A label on the USB stick would have been a really cool addition but a magic marker works just as well.
The only recommendation I would suggest is the addition of an internal lithium ion battery. The pen is tethered to your computer by a USB 2.0 cable, which provides the power and the input data for the electrical component being tested. So my recommendation for an internal battery is due to my own laziness and nothing else. I like portability and adding a battery would then have me asking for a memory card like a microSD for measurement logging (which is already done by the connected computer). After those requests would be filled I’d keep asking for more and more features like an additional probe, a sandwich and a 3D printer for my birthday.
Some folks have asked for WiFi or Bluetooth connectivity instead of USB but that could interfere with the sensors (EMI). You just can’t please everyone.
The pen oscilloscope is exactly the size you would think it would be; the size of a multi-colored ink pen. The Wave Rambler VPO 1025 sits in your pocket and it’s up to you to figure out which pointy end you want facing which direction. The design has a clip like almost all pens do to keep the $96.99 device from falling out of your shirt or pant pockets. Don’t try to write with it, though. Bad idea. Also, even though the oscilloscope is capable of testing to this range don’t try to probe anything running 1,000 volts. Yes, it’s not the volts that kill you it’s the amps but why put the floating measurement (isolation voltage) to that kind of test when it is really rated at a maximum of 400Vs for the “I” version. Even that is pretty high for the size of this cool little device.
This tool was built with ergonomics in mind because it fits comfortably in the hand for long periods of time. You have to try out the small trackball mounted on the top of the pen in exactly the same spot you would place your index finger. If you’ve ever used a drawing tablet than you should feel right at home using the trackball on this pen. There is a slide switch so you can change out probes depending on your testing and the package includes an additional hook probe connection. Don’t expect lots of printed documentation with the Sain Smart VPO 10125. You can find all the details you would ever want at
The included USB stick has the most current driver and software for the pen oscilloscope so don’t worry too much about the software link at the bottom of the web page listed here. I did run into a few issues installing the Sain Smart software but that was because of all the security tools I have running on my machines. You shouldn’t have any problems unless you are running HIDS, which if you don’t know what HIDS is than you probably aren’t running it.
The measurements were crisp and accurate during my testing of the Wave Rambler 1025. Basically the pen is the probe and all the measurements are gathered and displayed on your USB connected computer. It didn’t seem to matter if I was using USB 3.0 (blue connection) or 2.0. It did matter quite a bit when I decided to test the pen using a spare microUSB to USB cable. The Sain Smart device knew right away that the cable was incorrect and asked me to check my connection. Being the tester I am, I didn’t change the connection and being the good product it was, it didn’t allow it to connect with the improper cable.
Sain Smart put plenty of thought into the PC Oscilloscope VPO software. The opening screen shows the user tips on how everything works and can be used. The pen operation itself is fairly straightforward since there aren’t too many ways to mess up the probe selection switch, the trackball or the user defined Z button. I haven’t figured out how to get the customizable Z button to make me a sandwich (it’s a hardware issue, I guess).
I enjoyed the screen showing me measurements as well as locations of where those measurements were taken. This gave me a visual representation of how the circuits worked based on where each probe touched. Being a visual person, this really helped me out when I was troubleshooting a TFT screen that had a bad HDMI output from the power management chip. I was able to see where the signal started and where it stopped along with the intermittent power changes that might have been impossible to detect using a traditional multimeter.
A little bit of solder and my TFT screen was fixed. It took me longer to set up my solder station than it did to test the board and locate the fault. That saved me $45 in under 15 minutes. I would be interested in porting the Sain Smart software over to a microcomputer like the Raspberry Pi. That would give me even greater flexibility for those odd jobs that need a quick diagnostic tool to repair the damaged circuit.
From my vantage point, I see great potential for the Sain Smart Wave Rambler 1025 pen oscilloscope. At under $100 bucks, this tool will pay for itself in a few projects. Anyone working on microcomputers, circuits, radios or pretty much anything besides a puppy or a sandwich will need such a device. As the Internet of Things (IoT) becomes more of a daily reality, fixing your own gadgets will require more sophisticated tools like a pen oscilloscope instead of a hammer and a screwdriver.