Automatically re-connecting low-voltage cut-outs for 12 and 24 volt battery systems

via Dangerous Prototypes

KA7OEI writes:

In a previous post I described a simple circuit that provided a low-voltage cut-out that could be used in a battery-operated system – see the article “A latching low-voltage disconnect for 12 volt lead-acid and lithium batteries”. That circuit – intended mostly for lithium-based batteries – required manual intervention to “reset” the device, intended for those situations where you wanted to provide manual intervention in resetting the circuit to prevent causing harm to the battery – and maybe the gear connected to it.
This circuit is different from that described in the link above, intended mostly for lead-acid based systems where an automatic reconnect of the battery is required upon application of charge current.

More details on KA7OEI’s blog.

Friday Product Post: Move on RVR

via SparkFun: Commerce Blog

Hello everyone! We are happy to announce that our Basic and Advanced Autonomous Robotics Kits for Sphero RVR are now shipping, and that's not all - we also have the the micro:bit Club Kit and the new PICkit 4. But wait, there's even more: we have a limited edition of our popular RedBoard Artemis that we've dubbed the SnowBoard!

SparkFun Artemis SnowBoard

SparkFun Artemis SnowBoard

DEV-15839
$19.95

This SparkFun Artemis SnowBoard is a limited edition version of the RedBoard Artemis. There are only 250 units available - once they're gone, they're gone forever. Luckily for you, you can pick one of these boards up for free today only! This offer starts at 6 a.m Mountain Time, to get you SnowBoard for free! We expect them to go fast. This item is not available for resell.

Rules:

  • Add the SparkFun Artemis SnowBoard to your cart!
  • Use code "SNOWBOARD19" during checkout when your cart reaches $75 or more (not including this board or shipping/tax/discounts)

Also, don't forget, today is the LAST DAY for our Week of Deals sale. Stock up for 2020 projects and find your last-minute gifts, all in one place! Now onto new products!


RVR on over!

SparkFun Basic Autonomous Kit for Sphero RVR

SparkFun Basic Autonomous Kit for Sphero RVR

KIT-15302
$119.95
SparkFun Advanced Autonomous Kit for Sphero RVR

SparkFun Advanced Autonomous Kit for Sphero RVR

KIT-15303
$164.95

The SparkFun Basic Autonomous Kit for Sphero RVR provides an expansion set of sensors to the Sphero RVR platform. Meanwhile, the SparkFun Advanced Autonomous Kit for Sphero RVR provides all the functionality of the basic kit, with the addition of time-of-flight distance sensing in the front and rear. Based around Raspberry Pi’s small yet powerful Zero W model, the kit provides both global positioning and vision to the Sphero RVR (not included).


Sphero RVR - Programmable Robot

Sphero RVR - Programmable Robot

ROB-15304
$249.99 $199.00

Of course, you'll need to pick up a Sphero RVR to operate these kits, so why not pick one up while it's on sale! Fully capable out of the box, yet able to be expanded upon easily, the RVR is a perfect starting point for learning all about robotics. With tank treads and powerful, durable motors, the RVR can travel over most surfaces with ease using a highly advanced control system. In addition, on-board sensors such as encoders, an IMU and a color sensor make building a more advanced robot incredibly easy.


micro:bit Club Kit - Go Bundle 10-Pack

micro:bit Club Kit - Go Bundle 10-Pack

KIT-15803
$159.95

This micro:bit Club Kit contains ten micro:bit Go Bundles that provide you with everything you need to get hooked up and powered. This kit includes the micro:bit, a short USB cable, a AAA battery holder and AAA batteries. Also inside the Go Bundle you will find a Quick Start Guide, with four unique ideas to get you started with micro:bit! The Go Bundle is a quick and economical way to get started with the micro:bit.


MPLAB PICkit 4 In-Circuit Debugger

MPLAB PICkit 4 In-Circuit Debugger

PGM-15797
$49.95

This is the PICkit 4, the official programmer from Microchip. The PICkit 4 allows debugging and programming of PIC®, dsPIC®, AVR, SAM and CEC flash microcontrollers, and MPUs, using the powerful graphical user interface of the MPLAB X Integrated Development Environment (IDE). The MPLAB PICkit 4 is connected to a PC using a high-speed 2.0 USB interface, and can be connected to the target via an 8-pin Single In-Line (SIL) connector.


That's it for this week! As always, we can't wait to see what you make! Shoot us a tweet @sparkfun, or let us know on Instagram or Facebook. We’d love to see what projects you’ve made!

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Code the Classics on sale now

via Raspberry Pi

TL;DR: we made a fully automated luxury gay space communist type-in-listing book. Buy it now and get it in time for Christmas.

Code the Classics cover

Back in the dawn of time, in the late 1980s, I grew up on a diet of type-in computer game listings. From the BBC Micro User Guide, to The Micro User magazine, to the ubiquitous Usborne books: an hour or two of painstaking copying and a little imagination would provide you with an experience which wasn’t a million miles away from what you could buy on the shelves of your local computer store.

Can you believe they did “Machine Code for Beginners”?

The simple act of typing in a game helped to familiarise you with a programming language (usually a dialect of BASIC), and by making mistakes you could start to understand what other, more intentional changes might accomplish. Some of the earliest games I wrote started off as heavily modified versions of type-in listings; in fact, one of these made a sneaky reappearance on this blog last year.

Fast forward to the present day, and aside from regular appearances in our own MagPi and Wireframe magazines, type-in listings have faded from view. Commercial games, even casual ones, have become much more sophisticated, beyond what you might expect to be able to enter into a computer in a reasonable amount of time. At the same time, tools like Unity remove the need to develop every title from the ground up.

But there’s still a lot to be said for the immediacy of the type-in experience. Three years ago, we asked ourselves whether we could make a type-in game listing book for the modern era. The end result, of which we’re launching the first volume today, is Code the Classics. David Crookes and Liz Upton will take you behind the scenes of the creation of five classic arcade games, and then I’ll show you how to implement a simple Python game inspired by each one.

Cavern

Substitute Soccer

Developing retro arcade games has been a hobby of mine since those early BBC Micro days, and I spent many happy evenings developing these titles, ably assisted by Andrew Gillett and Sean Tracey. It was important to us that these games be as close as possible to the standard of modern commercial casual games. With this in mind, we invited Dan Malone, famous among many other things for his work with The Bitmap Brothers, to provide graphics, and long-time game audio pro Allister Brimble to provide music and sound effects. I’ve known Dan for nearly twenty years, and have admired Allister’s work since childhood; it was an enormous pleasure to work with them, and we took the opportunity to snag interviews with them both, which you’ll also find in the book. Here’s Dan to offer you a taster.

Meet the artist behind Code the Classics

Subscribe to our YouTube channel: http://rpf.io/ytsub Help us reach a wider audience by translating our video content: http://rpf.io/yttranslate Buy a Raspberry Pi from one of our Approved Resellers: http://rpf.io/ytproducts Find out more about the #RaspberryPi Foundation: Raspberry Pi http://rpf.io/ytrpi Code Club UK http://rpf.io/ytccuk Code Club International http://rpf.io/ytcci CoderDojo http://rpf.io/ytcd Check out our free online training courses: http://rpf.io/ytfl Find your local Raspberry Jam event: http://rpf.io/ytjam Work through our free online projects: http://rpf.io/ytprojects Do you have a question about your Raspberry Pi?

We’ve pushed the boat out on the production values for the book itself too: think of it as an object from a parallel universe where Usborne made luxury hardbound coffee-table type-in listing books rather than paperbacks.

So although, like all our books, you can download this one for free, you’ll really want a physical copy of Code the Classics to have, and to hold, and to leave on your bedside table to club intruders with.

And while the listings are rather long, and fully-commented versions are available on GitHub, perhaps you should think about spending a rainy afternoon actually typing one in.

The post Code the Classics on sale now appeared first on Raspberry Pi.

New products: micro metal gearmotors with 15:1 gear ratio

via Pololu Blog

We have expanded our line of micro metal gearmotors to include versions with a 15:1 gear ratio. As with all of our other micro metal gearmotors, these units are available with five different motor options:

Each motor is available with or without an extended back shaft, which rotates at the same speed as the input to the gearbox and offers a way to add an encoder, such as our encoders for micro metal gearmotors (see the picture above). This makes ten new versions in all:

Rated
Voltage
Motor
Type
Stall
Current
(A)
No-Load
Current
(A)
No-Load Speed
(RPM)
Extrapolated
Stall Torque
Max Power
(W)


Single-Shaft
(Gearbox Only)


Dual-Shaft
(Gearbox & Motor)
(kg ⋅ cm) (oz ⋅ in)
12 V high-power,
carbon brushes
(HPCB)
0.75 0.06 2200 0.25 3.5 1.4 15:1 HPCB 12V 15:1 HPCB 12V dual-shaft
6 V high-power,
carbon brushes
(HPCB)
1.5 0.10 2100 0.25 3.5 1.3 15:1 HPCB 6V 15:1 HPCB 6V dual-shaft
6 V high-power
(HP)
1.6 0.07 2000 0.30 4.2 1.5 15:1 HP 6V 15:1 HP 6V dual-shaft
6 V medium-power
(MP)
0.67 0.04 1400 0.20 2.8 0.70 15:1 MP 6V 15:1 MP 6V dual-shaft
6 V low-power
(LP)
0.36 0.02 860 0.17 2.4 0.37 15:1 LP 6V 15:1 LP 6V dual-shaft

More detailed specifications for all our micro metal gearmotors can be found in their datasheet (2MB pdf).

These new versions bring our total micro metal gearmotor selection to 130 options, with gear ratios ranging from 5:1 to 1000:1! To see them all, visit our micro metal gearmotor category, and visit our metal gearmotor category to see all of our metal gearmotor options. Keep in mind if you don’t see an option that suits your application, for sufficient volumes, modifications such as customized output shafts are available.

Once you find the perfect gearmotors for your project, don’t forget to check out our great selection of accessories. These were all designed either specifically for our micro metal gearmotors or with their compatibility in mind:

Bob Clagett made an LED Christmas tree video game for his entire town to play

via Arduino Blog

Bob Clagett likes making holiday decorations. This year, however, he wanted to create something that didn’t just look nice, but was also interactive. What he came up with is a giant Christmas tree that is actually a video game!

His tree-shaped matrix uses seven rows of RGB LEDs attached to the top of the structure to drop simulated snowflakes, represented by white lights. The player moves a dot on the bottom right and left to dodge these falling flakes via a pair of large arcade-style buttons. When the controlling Arduino Mega sees that the player’s position is the same as a snowflake, the game ends.

As Clagett’s community can attest, the project looks like a lot of fun! Code for the build is available on GitHub.

To make our Christmas tree game light up in the way that we intend, we have to be able to control each LED in an entire strand of lights. Traditional lights just have power run to colored bulbs, which blink or stay lit all together. We found a strand of individually addressable LEDs that are made for outdoor use. This means that each light has a small circuit board attached to each bulb that will receive power and a data signal from a micro-controller. I’m using an Arduino as the micro-controller to send out a signal to each specific light among the many strands.

Our game is very simple, there is a “player” that is restrained to the lowest level of lights in our tree-shaped matrix. That “player” can move left or right to avoid falling “snow.” When the game is played, the player will move while white “snow” lights fall randomly from the top of the tree-shaped matrix. If the “player” and the “snow” occupy the same space on the matrix in the arduino code, you lose. When the game isn’t being played, I used a simple LED flash library to create a Christmasy-looking color series that flashes until someone activates the game.

Now that the game code is working, the lights are blinking appropriately, and the control buttons are moving the “player” around, it’s time to make it look like a tree. To do this, Josh and I drilled holes at even space along some thin PVC material and fed in the lights. Covering those light boards with ping pong balls will help diffuse the LED light and give the whole tree a polished and clean look. These seven LED light boards are then connected to a hub at the top of a 10-foot metal pole. To keep the pole firmly planted on the ground, I poured a bucket of concrete and fixed a pole holder into it.