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Discussion Starter #1
Not exactly off-topic but I've been working with someone on one of the DCC++ projects, where some of us are having issues with DCC commands not being received in the latest code. I've been thinking about it for a couple years now and finally bit the bullet. There is this small kit named DSO138 which gives you a single-channel oscilliscope. It's not the fastest thing in the world, I think it tops out around 200kHz, but for observing the DCC signal on the tracks it has plenty of power. Basically I'm learning how to use it as I go, since some of the features are hidden behind long-presses of the control buttons. Since the kits come from China, documentation is lacking but the assembly instructions are fairly clear and have pictures for orientation of the various components.

There are different versions of this kit, but if anyone is interested make sure you get the "mini" as that is the latest release. As the name suggests, this version is about half the size of the original and fits nicely in the hand at 3x3.5 inches. I already had some probes from years ago so I opted to install the BNC connector, which allows me to also get different styles of probes in the future. Once you get the unit assembled it has a built-in signal generator that you use to make two adjustments to true-up the displayed waveform, then you go through a menu option to self-center the displayed waveform and you're ready to go. Not too bad for about $20US!

The display is a little misleading. This unit can take inputs up to +/- 50V but the grid lines on the screen don't show you what the output is. Fortunately one of those hidden features adds realtime text on the screen providing the actual peak voltages and frequency so I can see that my track signal matches the power supply at 16V. All of the features are selected through three slide switches and four pushbuttons. It can be run from a battery but I'm powering it from a USB cable (just like a phone charger). You can also connect the USB port to your computer and download the data as it is collected, making it easy to go through things later. There appear to be a number of extra features on the circuits boards, so Ill probably have to read the forum dedicated to this device to find out what else is possible.

Anyway, all in all I'm very happy with the purchase and wanted to share!

542421
 

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i have a dual trace tek with storage, but a whole lot more money too ....
in the display above , the DCC waveform shows that it rises gradually and then peaks on the extents ....in my case the rise is more abrupt, and the peak less gradual .. a more 'square' waveform ...
but i was thinking it actually doesn't make a whole lot of difference in the final outcome ??
 

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Discussion Starter #3
It's also possible that my trimmer adjustments aren't quite right yet, or there could be some capacitance from the perfboard I built my control circuit on... But yeah, as long as the signal is clear enough for a simple edge-detector to pick it up and the timing is right, the decoders should have no trouble with it.
 

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I had one of the earlier DSO138 kits , it was interesting to see what the capabilities are. I sent it to someone a while back, it didn't do what I needed. Unfortunately, for most of what I do with a 'scope, it's not nearly good enough. Looking at DCS and TMCC signals and uP board debugging is beyond it's capabilities.

I kept looking. On the bench, I have a dual-trace 100mhz digital 'scope, there are tons of them for $250-400 available, and they will serve for all but the most demanding applications.

For portability, I have the Mustool MDS8207, $85.32 and free shipping from US distributer. It gives you a 40mhz scope channel and a complete multi-meter in one package. For a pocket sized tool, this one is hard to beat for the price.

 

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Wow, that IS an impressive multimeter! I've never seen one with a scope built in. I'll have to keep that in mind.
 

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It actually works quite well. If I have a complaint, it's that this is one you really do have to read the manual to use it. Once I figured out some of the oddities, I really like it. It has so many features they did some interesting things to select them all.
 

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I bought one a number if years ago and have never used it. I tested it to be sure it worked and anyone who wants it can have it. No charge. It's in Anderson Indiana. If you are interested drop me a line.
[email protected]
 

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