Faux Radar Uses Ultrasound & Python

July 18, 2020 by Lewin Day 25 Comments

Radars are simply cool, and their portrayal in movies and TV has a lot to do with that. You get a sweet glowing screen that shows you where the bad guys are, and a visual representation of your missiles on their way to blow them up. Sadly, or perhaps thankfully, day to day life for most of us is a little less exhilarating. We can make do with a facsimile of the experience instead.

The project consists of an Arduino Uno outfitted with an ultrasound module that can do basic range measurements on the order of tens of centimeters. The module is then placed on a servo and scanned through a 180 degree rotation. This data is passed back to a computer running a Python application, which plots the results on a Plan Position Indicator, or PPI – the sweeping display we’re all so familiar with.

While it’s unlikely you’ll be using such a setup to engage bandits, it could prove as a useful module for robot navigation or similar applications. We’ve seen ultrasonic transducers used for exactly that. Video after the break.

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A Z80 Board With Very Few Parts

July 17, 2020 by Al Williams 25 Comments

The Z80 is one of those old CPUs that is both obtainable and easy to work with — at least in some versions. [Doctor Volt] put together what may be the simplest possible setups to get a working Z80 system. He has the processor, of course. But everything else — clock, memory, and power — are from an Arduino Mega 2560. You could argue that’s two chips, but the board actually has several chips on it. On the other hand, you could probably pull off the same stunt with a bare ATMega 2560.

We’ve seen this done before, but usually with a few more support chips. If you are a purist, [Doctor Volt] also has some Z80 and CP/M experiments where the Arduino only acts as a disk drive for the computer and there are only two support chips. There are three videos for both projects that you can see below.

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Bluepill Copies Code So You Don’t Have To

July 17, 2020 by Al Williams 5 Comments

You really should learn to read Morse code. But if you can’t — or even if you can, and just want a break — you can always get a computer to do it. For example, [jmharvey1] has a decoder that runs on a cheap Bluepill dev board.

The device uses a touchscreen and a few common components. The whole thing cost about $16. You can see it at work along with a description of the project in the video below.

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This Soap Dispenser Will Crush Your Germs

July 17, 2020 by Sharon Lin 12 Comments

When it comes to cleaning your hands, [Arnov Sharma] is not messing around. He built an automatic soap dispenser using ultrasonic sensors, a stepper motor for activating the pump, and 3D printed components for housing a bottle of soap – a spectacular display of over-engineering. At least he won’t be needing to stand in line at the supermarket for motion detection soap dispensers anytime soon.

Initially, he had the idea to build the dispenser using a common servo motor-based method. This would involve activating motors to push down on the plunger for the soap bottle to dispense soap. Instead, he for a different approach that ended up being fairly straightforward in theory, although the execution is pretty involved.

Model of the soap dispenser made in Fusion 360

He started off by 3D printing the compartment where the soap bottle would sit and the structural support for the Z-axis rail that would be pushing down on the soap bottle. It’s similar to the type of linear actuator you might find in a 3D printer or PCB mill, where a motor controls a rotating screw that moves the carriage across a belt. (We presume the linear rail came first, and the ultrasonic soap dispenser second.)

In this build, there are two additional rods added to help support the lever pressing down on the soap dispenser.

The setup is controlled by an Arduino, which triggers the movement from the linear actuator if it receives a signal from an ultrasonic sensor. He’s added the model files and Arduino code for other makers curious about building a similar project. Check out his video for the soap dispenser in action – the stepper motor definitely makes for a much more powerful plunge than you might expect.

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Four On The Floor For Your Virtual Race Car

July 17, 2020 by Al Williams 2 Comments

There was a time when building realistic simulations of vehicles was the stuff of NASA and big corporations. Today, many people have sophisticated virtual cockpits or race cars that they use with high-resolution screens or even virtual reality gear. If you think about it, a virtual car isn’t that hard to pull off. All you really need is a steering wheel, a few pedals, and a gear shifter. Sure, you can build fans to simulate the wind and put haptics in your seat, but really the input devices alone get you most of the way there. [Oli] decided he wanted a quick and easy USB gear shifter so he took a trip to the hardware store, picked up an arcade joystick, and tied it all together with an Arduino Leonardo. The finished product that you can see in the video below cost about $30 and took less than six hours to build.

The Leonardo, of course, has the ability to act like a USB human interface device (HID) so it can emulate a mouse or a keyboard or a joystick. That comes in handy for this project, as you would expect. The computer simply has to read the four joystick buttons and then decide which gear matches which buttons. For example up and to the left is first gear, while 4th gear is only the down button depressed. A custom-cut wooden shifter plate gives you the typical H pattern you expect from a stick shift.

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Arduino Plays NES Games

July 15, 2020 by Bryan Cockfield 14 Comments

Watching the advancement of technology is interesting enough by looking at improved specifications for various components as the years go by. But clock speeds, memory size, and power consumption are all fairly intangible compared to actual implementation of modern technology when compared to days of yore. For example, this $40 microcontroller can do what a video game console was able to do in the 80s for a tenth of the (inflation adjusted) price.

The NESDUE is an emulator for NES games which runs completely on an Arduino Due. The Arduino does have some limitations that have to be worked around to get the Nintendo to work, though. For one, it needs to be overclocked to be playable and it also needs a workaround to get past the memory limit of 96 kB of RAM. From there, a small screen is wired up along with a controller (from a Super Nintendo) and the gaming can begin.

This is an impressive feat for an Arduino platform to accomplish, especially with the amount of memory tweaking that has to happen. This might be the most advanced gaming system available that runs everything on an Arduino, right up there with the Arduinocade which can provide an arcade-like experience straight from the Arduino as well.

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Surgery On The Arduino IDE Makes Bigger Serial Buffers

July 13, 2020 by Al Williams 20 Comments

It is pretty well-known that I’m not a big fan of the Arduino infrastructure. Granted, these days you have more options with the pro IDE and Platform IO, for example. But the original IDE always gives me heartburn. I realized just how much heartburn the other day when I wanted to something very simple: increase the receive buffer on an ATmega32 serial port. The solution I arrived at might help you do some other things, so even if you don’t need that exact feature, you still might find it useful to see what I did.

Following this experience I am genuinely torn. On the one hand, I despise the lackluster editor for hiding too much detail from me and providing little in the way of useful tools. On the other hand, I was impressed with how extensible it was if you can dig out the details of how it works internally.

First, you might wonder why I use the IDE. The short answer is I don’t. But when you produce things for other people to use, you almost can’t ignore it. No matter how you craft your personal environment, the minute your code hits the Internet, someone will try to use it in the IDE. A while back I’d written about the $4 Z80 computer by [Just4Fun]. I rarely have time to build things I write about, but I really wanted to try this little computer. The parts sat partially assembled for a while and then a PCB came out for it. I got the PCB and — you guessed it — it sat some more, partially assembled. But I finally found time to finish it and had CP/M booted up.

The only problem was there were not many good options for transferring data back and forth to the PC. It looked like the best bet was to do Intel hex files and transfer them copy and paste across the terminal. I wanted better, and that sent me down a Saturday morning rabbit hole. What I ended up with is a way to make your own menus in the Arduino IDE to set compiler options based on the target hardware for the project. It’s a trick worth knowing as it will come in handy beyond this single problem.

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