Analyzing Hobby Motors with an Oscilloscope

via hardware – Hackaday

We always like finding new excuses reasons to use our test equipment, so we couldn’t help but be intrigued by this tip from [Joe Mosfet]. He uses the ever-popular Rigol DS1054Z to demonstrate the differences between a handful of brushless motors when rotated by his handheld drill at a constant RPM. Not only is he able to identify a blown motor, but it allows him to visualize their specifications which can otherwise seem a bit mystifying.

One wire from each motor is used as the ground, and channels one and two are connected to the remaining wires. Despite the DS1054Z having four channels, [Joe] is actually only using two of them here. The third channel being displayed is a virtual channel created by a math function on the scope.

After wiring them up, each motor got put into the chuck of his drill and spun up to 1430 RPM. The resulting waveforms were captured, and [Joe] walks us through each one explaining what we’re seeing on the scope.

The bad motor is easy to identify: the phases are out of alignment and in general the output looks erratic. Between the good motors, the higher the Kv rating of the motor, the lower voltage is seen on the scope. That’s because Kv in the context of brushless motors is a measurement of how fast the motor will spin for each volt. The inverse is also true, and [Joe] explains that if he could spin his 2450Kv motor at exactly 2450 RPM, we should see one volt output.

Beyond demonstrating the practical side of Kv ratings, [Joe] also theorizes that the shape of the wave might offer a glimpse into the quality of the motor’s construction. He notes his higher end motors generate a nice clean sine wave, while his cheaper ones show distortion at the peaks. An interesting note, though he does stress he can’t confirm there’s a real-world performance impact.

Last year we featured a similar method for identifying bad brushless motors using a drill press and an oscilloscope, but we liked that [Joe] went through the trouble of testing multiple motors and explaining the differences in their output.

[via /r/multicopter]

Free PCB coupon via Facebook to 2 random commenters

via Dangerous Prototypes

IRToy-600x369

Every Friday we give away some extra PCBs via Facebook. This post was announced on Facebook, and on Monday we’ll send coupon codes to two random commenters. The coupon code usually go to Facebook ‘Other’ Messages Folder . More PCBs via Twitter on Tuesday and the blog every Sunday. Don’t forget there’s free PCBs three times every week:

Some stuff:

  • Yes, we’ll mail it anywhere in the world!
  • We’ll contact you via Facebook with a coupon code for the PCB drawer.
  • Limit one PCB per address per month, please.
  • Like everything else on this site, PCBs are offered without warranty.

We try to stagger free PCB posts so every time zone has a chance to participate, but the best way to see it first is to subscribe to the RSS feed, follow us on Twitter, or like us on Facebook.

Friday Product Post: Rocko the Walabot

via SparkFun: Commerce Blog

G'day, everyone, and welcome to another new product-filled Friday Product Post! Though not a cute little wallaby, we do have two versions of the new Walabot radio frequency tool that allows you to see through walls (more on that further down), a strip of 10 teeny-tiny APA102-2020 LEDs, as well as a large back panel for your SmartiPi Touch. All of these fine new products are available right now, so let’s dive in and take a closer look!

Look through walls like Superman!

Walabot Developer

SEN-14535
$599.95

The Walabot Developer is a programmable 3D sensor inside a protective enclosure that looks into objects using radio frequency technology. This technology breaks through known barriers, bringing highly sophisticated sensing capabilities to your fingertips. This Walabot Developer version uses an 18-antenna array to illuminate the area in front of it and sense the returning signals. The signals are produced and recorded by a VYYR2401 A3 System-on-Chip integrated circuit. They are then communicated to a host device (like your phone or computer) using a USB interface, which is implemented using a Cypress controller.


Walabot Starter

SEN-14534
$149.95

If you are looking for something less expensive than the Walabot Developer, check out the Starter version instead. This little guy is very similar to the Developer above, but instead of an 18-antenna array, the Starter only has three antennas. Also, this Walabot can’t see through walls like its older sibling, but it is still capable of short-range imaging as well as target and breathing pattern detection.


SMD LED - RGB APA102-2020 (Pack of 10)

COM-14608
$4.95

This version of the APA102 is an astoundingly tiny, 2020-sized (2x2mm) SMD LED. With an integrated control circuit embedded, the APA102-2020 is incredibly bright and colorful. If you look really closely, you can see the tiny gold chip hidden in there, along with minuscule gold wires connecting the chip to the LED. This miniaturized version of the APA102C LEDs found in our Lumenati line is perfect for applications needing a bit of color while not possessing a lot of real estate.


SmartiPi Touch Back Cover (Large)

COM-14572
$9.95

Here is a large cover to protect all of the HATs that you have for the Raspberry Pi that’s attached to your SmartiPi Touch. This easy-to-install back cover screws into the back VESA mounts on the SmartiPi Touch with the four included screws. The cover allows you to protect HAT boards and other electronic components that you might want for your project. Each is made out of ABS plastic and can be easily cut, drilled or otherwise modified for any application or use. Additionally, the cover helps protect the ethernet and USB ports on the Pi B+, 2 and 3.


Alrighty, ladies and gentlemen, that’s it for this week’s diverse Friday Product Post! As always, we can’t wait to see what you make with these products! Shoot us a tweet @sparkfun, or let us know on Instagram or Facebook. We’d love to see what projects you’ve made!

Thanks for stopping by. We’ll see you next week with even more fantastic new products!

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This IoT Pet Monitor barks back

via Raspberry Pi

Jennifer Fox, founder of FoxBot Industries, uses a Raspberry Pi pet monitor to check the sound levels of her home while she is out, allowing her to keep track of when her dog Marley gets noisy or agitated, and to interact with the gorgeous furball accordingly.

Bark Back Project Demo

A quick overview and demo of the Bark Back, a project to monitor and interact with Check out the full tutorial here: https://learn.sparkfun.com/tutorials/bark-back-interactive-pet-monitor For any licensing requests please contact licensing@break.com

Marley, bark!

Using a Raspberry Pi 3, speakers, SparkFun’s MEMS microphone breakout board, and an analogue-to-digital converter (ADC), the IoT Pet Monitor is fairly easy to recreate, all thanks to Jennifer’s full tutorial on the FoxBot website.

Building the pet monitor

In a nutshell, once the Raspberry Pi and the appropriate bits and pieces are set up, you’ll need to sign up at CloudMQTT — it’s free if you select the Cute Cat account. CloudMQTT will create an invisible bridge between your home and wherever you are that isn’t home, so that you can check in on your pet monitor.

Screenshot CloudMQTT account set-up — IoT Pet Monitor Bark Back Raspberry Pi

Image c/o FoxBot Industries

Within the project code, you’ll be able to calculate the peak-to-peak amplitude of sound the microphone picks up. Then you can decide how noisy is too noisy when it comes to the occasional whine and bark of your beloved pup.

MEMS microphone breakout board — IoT Pet Monitor Bark Back Raspberry Pi

The MEMS microphone breakout board collects sound data and relays it back to the Raspberry Pi via the ADC.
Image c/o FoxBot Industries

Next you can import sounds to a preset song list that will be played back when the volume rises above your predefined threshold. As Jennifer states in the tutorial, the sounds can easily be recorded via apps such as Garageband, or even on your mobile phone.

Using the pet monitor

Whenever the Bark Back IoT Pet Monitor is triggered to play back audio, this information is fed to the CloudMQTT service, allowing you to see if anything is going on back home.

A sitting dog with a doll in its mouth — IoT Pet Monitor Bark Back Raspberry Pi

*incoherent coos of affection from Alex*
Image c/o FoxBot Industries

And as Jennifer recommends, a update of the project could include a camera or sensors to feed back more information about your home environment.

If you’ve created something similar, be sure to let us know in the comments. And if you haven’t, but you’re now planning to build your own IoT pet monitor, be sure to let us know in the comments. And if you don’t have a pet but just want to say hi…that’s right, be sure to let us know in the comments.

The post This IoT Pet Monitor barks back appeared first on Raspberry Pi.

The Best Enginursdays You May Have Missed

via SparkFun: Commerce Blog

Every week, one of our hardworking engineers takes time away from creating new stuff and pours their heart into a special project, or takes a deeper dive into the world of electronics. This week we’ve decided to let them continue their work unimpeded and reflect on a few recent Ennginursdays that are worth another look. We’ve got something for everyone, from the creation of the SparkX Lab to detecting the most subtle of knob changes.

Before we get back to our regularly-scheduled Enginursdays, enjoy something you may have missed and ask yourself, “Do I truly know enough about connectors?” We’ll see you next week with a fresh topic!

 

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Laser Galvo Control via Microcontroller’s DAC

via hardware – Hackaday

Mirror galvanometers (‘galvos’ for short) are the worky bits in a laser projector; they are capable of twisting a mirror extremely quickly and accurately. With two of them, a laser beam may be steered in X and Y to form patterns. [bdring] had purchased some laser galvos and decided to roll his own control system with the goal of driving the galvos with the DAC (digital to analog) output of a microcontroller. After that, all that was needed to make it draw some shapes was a laser and a 3D printed fixture to hold everything in the right alignment.

The galvos came with drivers to take care of the low-level interfacing, and [bdring]’s job was to make an interface to translate the 0 V – 5 V output range of his microcontroller’s DAC into the 10 V differential range the driver expects. He succeeded, and a brief video of some test patterns is embedded below.

Instagram Photo

We have seen drawing shapes with lasers go in some really creative and interesting directions. For example, this amazing mechanical laser projector draws shapes using only 3D printed cams and gears, and this one draws on a glow-in-the-dark surface with a UV laser for a ghostly take on things.