First Hours with the SDS1102CML

The Siglent SDS1102CML arrived this afternoon and my kids and I have been having a good time with it. I’ve never turned on an oscilloscope before tonight. I’ve touched some older ones that were of questionable operating state, but not even seen the screens light up so as I write about my stumblings, keep this in mind.

The scope came out of the box looking pristine and solid as I’d expected from the reviews I watched & read. The plastic casing does seem to be solid. I’m not at all worried about breaking it. My first impressions of the knobs was that they seemed to have an odd friction about them, but I found myself accustomed to them pretty quickly. The buttons are pleasingly soft and have nice tactile feedback. I didn’t have any trouble seeing the backlight on the buttons.

Interface & Firmware

I had watched a few Siglent product reviews on YouTube so that gave me a good first run at the menu system and how to navigate through it. (If that EEVBlog guy can do it surely I can.) With only that information and my computer tech background, I found it easy enough to navigate the menus and determine how to get in and out of various menus. I ran the self test and confirmed that all the buttons, knobs and lights were working. Being a good system administrator, the next thing I checked was the firmware version. I was pleased to find it came with the latest: I must admit I was a bit disappointed not to test out the firmware update functionality. That firmware is getting to be about a year old.

I don’t know if that is normal for a device like this, but given that I did have it freeze up a couple times this evening, there are some bugs which I’d think would warrant a firmware upgrade if it was available. I think each time I had the SDS1102CML freeze up it was right about the time I pushed the blue “AUTO” button so I think that feature must be the cause. Simply turning it off and back on solved it each time.

One other thing. Nobody told me the interface has skins! Granted, this isn’t as advanced as my phone’s ability to change appearance. It is more like late 90s Winamp… but not that cool. Still, the ability to change my predominate screen color to my favored shades of green was a fun discovery. Inverting that so it was mostly pink was something my daughter really liked, but I quickly inverted the inversion back to a green amid the protests.

Baby’s First Waveforms

Next I wanted to see something actually oscillate. That is the point of this machine right? I hooked up a probe, set it to 1x (whatever that means) and attached ground to the ground lug in the bottom right corner and the probe to the 1khz lug immediately above. Success! I can haz waves!

So the thrill of getting the scope to measure itself wore off REAL quick. Time to break down some barriers! I’d seen someone mess with hooking up a speaker to a scope and detecting voice signals so I grabbed the handy Baofeng speaker mic and hooked the ground lug up to the ground on the small plug and with much anticipation connected dualplugthe probe to the tip. I promptly got nothing. Okay, it looked a bit noisier, but mostly nothing. I spoke a little louder and it looked a little different, but pretty much a straight line across the screen.

As I aimlessly twisted knobs and pushed buttons, I started seeing interesting waveforms. At some point I realized the volts/div (right term?) vertical channel knob thingys needed to be spun around until they were set to the minimum values (2mV) and then I could see activity. Time to show off my technical prowess to my kids! (They are most impressed with anything I do. I hope they never grow up so I get to see their wonder forever I don’t lose the ego boost.)

PTT is depressed when the yellow signal is thin.

We also discovered that if you ground the probe to MIC+ and hold the probe against MIC- (it won’t fit on its own), you can see a change when pushing in the Push-To-Talk button. It gets much less noisy as you can see in this picture.

This wavy thing they could control with their voice grabbed the attention as expected. All three kids in turn hummed, sang, talked, yelled and growled into the hand mic to see what they could get on the screen. It reminded me of the time I taught the oldest about conductivity and she ran around with the multimeter testing conductivity of random household items. Anyway, as they serenaded me, I twiddled knobs and, like a good dad, took pictures (of the waveforms they made, not the kids.) That print button drops a picture right to USB disks. Just plug a USB drive in and it dumps out .BMP files into a folder called BMP. Here are some samples of my kids exercising their vocal chords and imagination. I used ImageMagick’s mogrify command to convert to a suitable image format, mogrify -format png *.BMP. I can’t at the moment think of a more geeky Dad thing to do than post a slideshow of your kids voices on an oscilloscope.

Bonus Points: Figure out which of these is a 5-year-old boy growling.

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After the kids went to bed I found the sound of my own voice quickly grew uninteresting. I went out to the garage and dug up an old 5V Adafruit Tinker Mood Lamp project I’d put together for a girl scout group a few years ago with some bSDS00009linking LEDs. I put the first and second probe each on the ground side of two super bright LEDs and saw the voltage coming out of the LED in the circuit. Then I put one probe on either side of one LED and was able to see the higher voltage one one side versus the other. I figured the difference is the electricity turned into light. If I’m wrong, please tell me.

Sidebar: Maybe I’ll reprogram the trinket to fade the LEDs instead of blink. That’d be another interesting thing to watch on the scope. I must finish this blog entry fast so I’ll have time for that before my brain burns under the stress of new knowledge!

After observing the voltage drop across the LED, I played around with the menus under “Measure” and “Math” to see if I could come up with a calculated difference between the two waves. I’m sure this thing can do that, but it hasn’t yet accepted me into its heart so I was unable to coax these subtleties from it. Someday…

Linux all the USB Things

You’ve heard the cat say “If it fits, I sits”. Well this geek says, “If it has USB, I plug it in”. (Groan, dad joke!)

Yes, I plugged this fine piece of modern art into my Linux laptop and Ubuntu recognized it down to the product name. I haven’t played around with getting the EasyScope software running on Wine. Apparently the attenload linux software also has support for the scope, but at this point I figure I’ve filled my brain as much as I can which is why I came to these hallowed halls to dump its contents.

Here is the dmesg output for the USB connection to the scope.

[20099.897630] usb 1-2: USB disconnect, device number 8
[20230.500301] usb 1-2: new full-speed USB device number 9 using xhci_hcd
[20230.628832] usb 1-2: not running at top speed; connect to a high speed hub
[20230.629875] usb 1-2: New USB device found, idVendor=f4ec, idProduct=ee38
[20230.629878] usb 1-2: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[20230.629879] usb 1-2: Product: SDS1102CML
[20230.629881] usb 1-2: Manufacturer: Siglent Technologies Co,. Ltd.

What Next?

What other things should I do to give my shiny new toy some action and help me understand its subtleties? Better yet, what should I know to never ever do for fear of breaking it beyond repair? I once tried to use a multimeter on 220 mains for a baseboard heater. That multimeter was never the same and my vision took awhile to recover. I’d like to think I’ve learned from that experience, but your input is welcome!