Planet Arduino

There’s little question that an oscilloscope is pretty much a must-have piece of equipment for the electronics hacker. It’s a critical piece of gear for reverse engineering devices and protocols, and luckily for us they’re as cheap as they’ve ever been. Even a fairly feature rich four channel scope such as the Rigol DS1054Z only costs about as much as a mid-range smartphone. But if that’s still a little too rich for your taste, and you’re willing to skimp on the features a bit, you can get a functional digital oscilloscope for little more than pocket change.

While there are a number of very cheap pocket digital storage oscilloscopes (DSOs) on the market, [Peter Balch] decided he’d rather spin up his own version using off-the-shelf components. Not only was it an excuse to deep dive on some interesting engineering challenges, but it ended up bringing the price even lower than turn-key models. Consisting of little more than an Arduino Nano and a OLED display, the cost comes out to less than $10 USD for a decent DSO that’s about the size of a matchbox.

But not a great one. [Peter] is very upfront about the limitations of this DIY pocket scope: it can’t hit very high sample rates, and the display isn’t really big enough to convey anything more than the basics. But if you’re doing some quick and dirty diagnostics in the field, that might be all you need. Especially since there’s a good chance you can build the thing out of parts from the junk bin.

Even if you’re not looking to build your own version of the Arduino-powered scope [Peter] describes, his write-up is still full of fascinating details and theory. He explains how his software approach is to disable all interrupts, and put the microcontroller into a tight polling loop to read data from the ADC as quickly as possible. It took some experimentation to find the proper prescaler value for the Atmega’s 16MHz clock, but in the end found he could get a usable (if somewhat noisy) output with a 1uS sample rate.

Unfortunately, the Arduino’s ADC leaves something to be desired in terms of input range. But with the addition of an LM358 dual op-amp, the Arduino scope gains some amplification so it can pick up signals down into the mV range. For completion’s sake, [Peter] included some useful features in the device’s firmware, such as a frequency counter, square wave signal source, and even a voltmeter. With the addition of a 3D printed case, this little gadget could be very handy to have in your mobile tool kit.

If you’d rather go the commercial route, Hackaday’s very own [Jenny List] has been reviewing a number of very affordable models such as the DSO Nano 3 and the JYE Tech DSO150 build-it-yourself kit.

[Thanks to BaldPower for the tip.]

Hello everyone!

During July there was another competition which was quite fun, so from August and onwards we shall do it again. The winner ‘S.R.’ won the minor prize so the major prize jackpots into this month. Running these competitions are a way of saying thank you to my readers, and to generate some interaction. So …

All you have to do for a chance to win is the following:

1. Read the blog posts and articles in August, as there will be six questions you will need to answer placed randomly amongst the posts. To keep track, subscribe using one of the methods on the right hand side of this page
2. When you have answers for all six questions, email them to competition@tronixstuff.com
3. If you follow me on twitter (@tronixstuff) and retweet one post in August, you will receive two entries, so put your twitter address in your email.
4. On September the 1st, all the email addresses will be placed in a random draw and one selected. If the entry drawn has all six questions correct, they will win the major prize!
5. If the first entry drawn does not have six correct answers, they will win the minor prize, and the major prize will carry over until September, to be combined with the new major prize.

The prizes!

Major prize

The major prize for August consists of the following:

• One assembled, used JYE Tech Digital Storage Oscilloscope – from the kit review;
• One new pair of 315 MHz wireless data modules, as used in Getting Started with Arduino – Chapter Eleven;
• And something different, the new Texas Instruments MSP430 Launchpad kit, including evaluation board, two MCUs  and the USB cable.

Minor prize

The minor prize for August is John’s Fun with LEDs! pack, consisting of:

• ten each of red, green, yellow and orange 5mm LEDs;
• four RGB 10mm diffused LEDs
• three 74HC595 shift registers
• two Texas Instruments TLC5940 16-channel LED driver ICs
• two LM3914 bar graph/dot driver ICs
• 20 x 560 ohm 1% resistors (they missed the photo call)

Hopefully everyone can have some fun reading about electronics and learning along the way. As with any competition, there are a few rules:

1. If you have won a previous competition, you cannot enter
2. If you know me personally, you cannot enter
3. The prizes carry no warranty, we accept no liability for anything at all that they may cause
4. Prizes only include what is in the photograph, and will be sent via standard airmail free of charge
5. My decision is final
6. You can witness the draw in person with prior arrangement
7. The time used is Australian Eastern Standard Time (GMT: +10)

If you cannot wait for a chance to win, the DSO and and a range of LEDs are available from our friends at Little Bird Electronics.

So keep your eyes peeled and have fun!