A quick review of the HPS10se portable Oscilloscope from Velleman

I ordered this device about a year and a half ago for about $130USD. When I got it, I wasn’t terribly impressed but overall, for the price it’s not a bad unit. I figured it’s be nice to provide a short review of the device since there aren’t very many useful reviews out there. I have also done a video review which is posted on this page and on my Youtube channel at http://www.youtube.com/user/ElectroTark.


HPS10se Velleman Oscilloscope on the bench
HPS10se Velleman Oscilloscope on the bench

The HPS10se is a low cost oscilloscope with a backlit 128×64 screen. The video performance is actually OK and the waveform is reasonably easy to make out in most instances. This device boasts a 2MHZ bandwidth for analog signals and a 10MS/s sampling rate. While I have no doubt that these figures are true, my own tests show that any waveform shows severe degradation above about 1MHz, this is to be expected though.

HPS10se oscilloscope in the box

The unit comes with a single probe, no need for more since it only has one channel input. 🙂
There is an option on the probe for x10 measurement which can be handy for high voltage measurement up to 600V. I’ve never used that feature on this but it’s easy to access with only a single button press. The device takes 5 AA batteries and can be run with an external wall wart, though it isn’t included. I use an old 9V converter with a 2.1mm by 5.5mm barrel connector, seems to work OK. It is rated at 9V and you might be able to use a 12V pack, though it may generate extra heat on the DC converter on-board.
One problem I have with this device is the way it eats batteries, even when it’s off. Remember to remove the batteries when you’re not using it. As an extra note, it can charge NIMH batteries if they’re in there.

Oscilloscope with a square wave

The device has some standard measurement options such as V-Peak+, V-Peak-, V-Range and Watts and dB. Since this is a low cost unit, it does not have a direct measurement for frequency and you cannot set the trigger level, you can however set its slope (Fall and Rise). You have to measure the frequency indirectly either by looking at the ticks and counting or by using the markers that you set, moving the markers to the start and end of one waveform gives you a frequency measurement in Hz.
Here’s a quick video I made, watch it if you like…


Anyways, here are some pros and cons.
PROS:

  • Low cost, about $130 to $160
  • Reasonable feature set for the price
  • Screen is easy to read despite its low resolution
  • Good for general use, low frequency stuff in a pinch

CONS:

  • Eats batteries like candy, also an odd number to use, 5, which most batteries come in multiples of 2
  • Waveform display is kind of inaccurate
  • Stand flap on back is too short, tough to stand vertically
  • No trigger level function
  • No direct frequency measurement

In closing, I would recommend this for people getting into electronics but for doing anything else, spend the extra money for a good/decent oscilloscope. The price, again, is pretty good.

Coolant mixture sensor (psuedo-refractometer)

A bit ago I got the idea of trying to determine the mixture of coolant vs. water by detecting both light occlusion of the mixture and the wavelengths blocked / passed. This initial device is just a rough prototype that will assist me in determining a course of action in regards to overall design.
The idea behind the device is to have the sensor fitted on to any pipe attached to the machine where coolant goes through and give a live measurement of coolant mix and alert the operator if the mix gets too high or low. Also I’d like it to detect tramp oils that have been beaten in to the coolant.


Coolant meter board

The board itself is pretty simple, just a PIC16f690 hooked up to an rs232 driver and using three analog channels. I may in the future build a more sophisticated ADC board, but for now, this will do. The mcu is linked to the two rail to rail opamps, 7014D’s to be exact. they were needed to condition the signal from the LEDs.
Coolant meter test receptacle

The sensor area is basically a cup with a white LED as a light source for the sensor LEDs. The three LEDs are IR, Orange-red, and Green. The LED’s respond to wavelengths more energetic than the ones they emit, therefore, the selections I made. I did try a blue LED but the response wasn’t good at all. Hopefully it will provide useful data, hopefully.

Coolant meter terminal output

In order to make data easier to collect, I put rs232 communications on it. I can store and track data this way. Above is some of the terminal output. Notice that I’m taking 10000 samples… this has the effect of increasing, to a very limited degree, the resolution of the device. It is however fraught with error thus far…
Anyways, any data collected and the design of this is extremely preliminary. I’m not even sure it’s a valid or useful idea yet.
As an extra bonus, or punishment, here’s a video I made for this device.