Low-cost Autonomous Rover Will Drive Your Projects

October 29, 2018 by Tom Nardi 3 Comments

[Miguel] wanted to get more hands-on experience with Python, so he created a small robotic platform as a testbed. But as such things sometimes go, it turns out the robot he created is a worthy enough project in its own right. With a low total cost and highly flexible design, it might be exactly what you’re looking for. Who knows, it might even bootstrap that rover project that’s been wandering around the back of your mind.

The robot makes use of an exceptionally simple 3D printed frame. No complicated suspension to worry about, no fasteners to hold together multiple printed parts. It’s just a single printed “L” shaped piece that has mounts for the motors and front sensor board. As designed it simply drags its tail around, which should work fine on smooth surfaces, but might need a bit of tweaking if you plan on taking your new robotic friend on an outdoor adventure.

There’s a big open area on the “tail” to mount a Raspberry Pi, but you could really put whatever board or microcontroller you wish here. In the nose is an HC-SR04 ultrasonic sensor, which [Miguel] is using to perform obstacle avoidance in his Python code. A dual H-Bridge motor driver controls the pair of gear motors in the front to provide propulsion and steering, and a buck converter steps down the 7.4V from the 2S LiPo battery to power the electronics. He’s even included a mini breadboard so you can add circuits or sensors as experimental payloads.

If you’re looking for a slightly more advanced 3D printed robotics platform, we’ve seen our fair share. From the nearly fully printed Watney to a tank that looks like it’s ready for front-line combat.

Learn To Loop The Python Way: Iterators And Generators Explained

September 19, 2018 by Ben James 17 Comments

If you’ve ever written any Python at all, the chances are you’ve used iterators without even realising it. Writing your own and using them in your programs can provide significant performance improvements, particularly when handling large datasets or running in an environment with limited resources. They can also make your code more elegant and give you “Pythonic” bragging rights.

Here we’ll walk through the details and show you how to roll your own, illustrating along the way just why they’re useful.

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Make Your Python Prettier With Decorators

August 31, 2018 by Ben James 23 Comments

Many Pythonistas are familiar with using decorators, but far fewer understand what’s happening under the hood and can write their own. It takes a little effort to learn their subtleties but, once grasped, they’re a great tool for writing concise, elegant Python.

This post will briefly introduce the concept, start with a basic decorator implementation, then walk through a few more involved examples one by one.

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Rover V2 Handles Stairs As Easily As The Outdoors

August 15, 2018 by Donald Papp 10 Comments

Rover V2 is an open-source, 3D-printable robotic rover platform that has seen a lot of evolution and development from its creator, [tlalexander]. There are a number of interesting things about Rover V2’s design, such as the way the wheel hubs themselves contain motors and custom planetary gearboxes. This system is compact and keeps weight down low to the ground, which helps keep a rover stable. The platform is all wheel drive, and moving parts like the suspension are kept high up, as far away from the ground as possible. Software is a custom Python stack running on a Raspberry Pi that provides basic control.

The Rover V2 is a full mechanical redesign of the previous version, which caught our attention with its intricate planetary gearing inside the wheel hubs. [tlalexander]’s goal is to create a robust, reliable rover platform for development that, thanks to its design, can be mostly 3D printed and requires a minimum of specialized hardware.

Stop Using Python 2: What You Need To Know About Python 3

August 15, 2018 by Ben James 113 Comments

Though Python 3 was released in 2008, many projects are still stuck on Python 2.

It’s understandable that porting large existing codebases to a new version is a prospect which sends a shiver down many a developer’s spine. But code inevitably needs to be maintained, and so when all the shiny new features that would fix everything are in a new version, is it really worth staying rooted in the past?

We’ll take you through some of the features that Python 2 programs are missing out on, not only from 3.0 but up to the current release (3.7).

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Python Resurrects Dot Matrix Printing

August 9, 2018 by Al Williams 54 Comments

These days a printer — especially one at home — is likely to spray ink out of nozzles. It is getting harder to find home laser printers, and earlier printer technologies such as dot matrix are almost gone from people’s homes even if you’ll still see a few printing multipart forms in some offices.

[Thomas Winningham] bought an old Commodore dot matrix printer in a fast food parking lot for $20. How hard could it be to get it working? How hard, indeed. Check out the video below to see the whole adventure. The principle behind the printer is simple enough. The head has one or two rows of pins each controlled by a solenoid. The head moves across the paper and your job — should you decide to accept it — is to make the pins push out at the right spot. An ink ribbon like a typewriter uses — oh yeah, more vanishing tech — leaves ink on the paper where it gets punched by the pin.

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Find Your Level – Extracting NES Game Data Using Python

August 1, 2018 by Sven Gregori 8 Comments

Just this summer, the Nintendo Entertainment System had its 35th release anniversary, and even after years of discontinuation, it is still going strong in the hacker community. Exhibit A: [Matthew Earl]. For one of his upcoming projects, [Matthew] needed to get his hands on the background images of the NES classic Super Mario Bros. Instead of just getting some ready-rendered images and stitching them together, he decided to take care of the rendering himself, once he extracts the raw game data.

Since there is no official source code available for Super Mario Bros, [Matthew] used a disassembled version to get started looking for the image data. To avoid reading through thousands of lines of assembly code, and to also see what actually happens during execution, he wrapped the game’s ROM data into py65emu, a Python library emulating the 6502, the CPU that drives the NES. By adding a simple wrapper around the emulator’s memory handler that tracks reads on uninitialized data, [Matthew] managed to find out which parameters he needs to feed to the parser routine in order to get the image tile data. After an excursion into the Picture Processing Unit (PPU) and its memory arrangements, [Matthew] had everything he needed to create the Python script that will render the game background straight from its ROM data.

Even if extracting NES game data is not your thing, the emulator concept [Matthew] uses might be still worth a read. On the other hand, if you want to dig deeper into the NES, you should definitely have a look at emulating an SNES game on a NES, presented on the NES itself.