| Electronics > Beginners |
| Purchased an oscilloscope but did I make a mistake? (re: newbie + Arduino, etc) |
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| IDEngineer:
Guess what is the best tool for debugging embedded software (aka firmware)? An oscilloscope. You're playing with Arduinos, which are embedded firmware platforms. You'll soon be controlling an I/O pin with your software and something won't be working properly... and you can connect up your scope and know for certain exactly what is happening on that pin. And the circuitry it's connected to. The scope's multiple channels will allow you to correlate your signals with what is happening elsewhere in your circuit. And on and on. You just made the single best investment in hardware+software development. In a few months you'll wonder how you could have ever gotten by without it. |
| Old Printer:
--- Quote from: sofakng on June 11, 2018, 07:13:03 pm ---I've been trying to learn more about electronics but typically experiment with microcontrollers (Arduino, Teensy, etc) and digital signals/communication. However, I've been looking to learn more and have purchased ATmega 328 chips and 32u4 chips trying to program them without Arduino so I can learn more about the platform and electronics, etc. Anyways, eBay had a 20% off coupon last weekend and I impulse purchased a Rigol DS1054Z for about $300 shipped which seemed like a steal. I've been waiting to purchase one until a deal came around but now I'm wondering if I should have even purchased it at all? (or should I return it?) I am hoping the oscilloscope can help me learn electronics and see how things are working (SPI communication, etc) but I don't think I will ever really use it to troubleshoot any circuits? (ie. how do clock signals work and understanding digital circuits and how they interact with the clock, etc) For example, my projects include building a Bluetooth to USB HID keyboard controller (WIZnet chip + ATmega32u4 which uses SPI), interfacing with home automation systems (RS232), etc. I know it's hard to give advice, but if anybody has anything that might be useful please let me know :) (EDIT: I'm currently using a Fluke 87 V multimeter but again, I though the osciliiscope could help me learn how things work more than having any other purpose) --- End quote --- I stupidly inserted my post into the OP's quote :( So here was my question: Did you buy it from an factory authorized dealer? The thing I worry about is that the factories tend to push warranty claims back on the dealer. The 20% off would be great, but not at the expense of a warranty hassle with a grey market seller. Does that mean ebay pays the seller the 20%? I have never seen a coupon like that. |
| rstofer:
This is a true story, the names have not been changed... A couple of days ago I was working with a Beaglebone Black and a UDEMY course on how Linux works on the board. Good course, by the way! I bought a USB->Serial cable with 3.3V output but I needed to PROVE that the green wire was TXD because it would be a really bad idea to stuff my TX output into the board TX output (something is going to get hot!). So, I connected my scope to the wire and used minicom to send characters. Sure enough they showed up on the scope. I then shorted green to white (TX -> RX) to form a loopback and made certain that echoed characters display on the terminal. Then I safely connected the gadget to the board and everything came out fine. All the boot messages were on the screen and the keyboard could send console commands - just the way it was supposed to work. No "I guess..." involved! No point to the story except to say that without a scope, this kind of testing can be real hard to do. Maybe a logic probe (which I have buried around here somewhere) but the scope is right there on my bench. Of course I'm going to use it. Scopes are unbelievably handy and the DS1054Z is a good example of an entry level scope. |
| rstofer:
For a simple project with the Arduino, look in File->Examples->Servo and pick Sweep. Connect your 10x probe to pin 9 and your probe ground to one of the ground connections. Then press the Auto button. After the scope displays an image you may need to shut down other channels - press their button twice. You may need to center the display vertically, press the Position knob (the small one above the Volts/Div knob). You may want a single pulse image, turn the Scale knob (lower right) to get 500 us/div as shown in the upper left of the screen. Now you should have a single pulse starting at the middle of the screen. The pulse width will vary. Servo pulses are varying width 1.0 ms to 2.0 ms (servo center is 1.5 ms) repeating about 20 times per second (50 Hz). The Arduino seems to overrun both ends, my scope shows 0.5 ms to 2.5 ms You should see something very close to 50 Hz in the freq counter display in the upper right corner of the screen. There, your first useful scope project. There are a number of other issues like x1 or x10 probe selection. Press the channel button and there will be a button associated with Probe - select that button then use the top left 'Intensity' button to select the x10 setting to match the probe. Push the knob to select it. In the end, you probably want 5.00V in the Volts/Div display in the lower left corner of the screen. |
| IDEngineer:
Oh man, I just can' t help it. >:D --- Quote ---Then press the Auto button... --- End quote --- ...and no more twiddling, right? Oh, wait, you'd better actually know how to use a scope because: --- Quote ---After the scope displays an image you may need to shut down other channels - press their button twice. --- End quote --- ...and you'd better know about the vertical amplifiers, because: --- Quote ---You may need to center the display vertically, press the Position knob (the small one above the Volts/Div knob). --- End quote --- ...and you'd best be familiar with the horizontal timebase too, because: --- Quote ---You may want a single pulse image, turn the Scale knob (lower right) to get 500 us/div as shown in the upper left of the screen. --- End quote --- ...so that finally, after compensating for that so-called "Auto" button with several manual adjustments: --- Quote ---Now you should have a single pulse starting at the middle of the screen. --- End quote --- Hopefully, the user will have played around (and I do really mean PLAYED around) with the scope for a while so that he doesn't have to rely solely on the so-called "Auto" button. To the original poster: There is another thread on here arguing about the supposed worthlessness of analog scopes, particularly since digital scopes have the magic "Auto" button. But this post I'm replying to perfectly illustrates why the "Auto" button is not the end-game for scopes. My advice is to utterly ignore the "Auto" button and just PLAY with your scope for a while so you get a nice feel for its basic operation. Then nobody will have to tell you about fixing the "Auto" button's bad guesses because you'll already have the display you want, no "Auto" button required. It will become second nature to you, and you'll have a great time learning and doing it. Apologies for the minor thread hijack, but I just couldn't let this one go. :horse: |
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