Interactive Projections Take Miniature Golfers to a Tiny World

Miniature golf is one of those pastimes that can be molded and redefined pretty much indefinitely. Like pinball machines which also come in an endless variety of flavors, each hole of a miniature golf course is a vignette with a theme designed to tie cleverly into its objective. Mini golf has come a long way from windmills and draw-bridges, and with technology thrown in the mix you end up with works of art like [Dan Rosenfeld’s] project, “Sleepwalkers” which go so far as to paint a holographic world for the player to interact with.

“Sleepwalkers” was commissioned by Urban Putt, a chain that accommodates for dense city spaces by building their courses indoors. Designed specially for its location, the hologram acts as a narrative told by tiny characters living within the walls of the historic building the golf course occupies. At a certain point during the game, a player is prompted to purposely place their ball into an opening in one of the old walls where it quickly rolls somewhere out of sight. When the player peeks through a series of holes dotted throughout the surface in order to find where it went, they discover another world sandwiched between wood beams and insulation. This becomes the setting of a short exchange with a character who the player must interact with in order to get their ball out of hock. The spectral glow and dimensionality of the wall’s inhabitants is created using a projection along with the Pepper’s Ghost illusion, a classic trick with angles and mirrors. Once the player’s hand enters into the Sleepwalker’s world through larger holes in the wall, a camera used for depth cues maps the projection to its presence. The tiny figure then uses the hand in a series of dioramas as a tool to climb on in order to reach the area where the player’s ball is trapped. After a joint effort, a linear actuator and sensor help to complete the illusion that the projected character is pushing the golf ball free into the real world where the player can then retrieve it and continue on to the next hole.

The traditional antics created by swinging pendulums and spinning windmills will always charm us, but the use of technology to take us into a new world will leave us with something more. You can see it on the faces of those interacting with [Rosenfeld’s] installation for the first time:

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Casing up the Teensy SDR

[Rich, VE3MKC] has made a lot of progress on his Software Defined Radio (SDR) which is based on a Teensy. His latest update shows off the hardware in an enclosure and a few new features.

When we looked at this in April of last year it was pretty much a proof-of-concept with components hanging loose from jumper wires. The new case mounts everything securely in a plastic Hammond enclosure with copper clad for the front and rear panels. The SoftRock SDR unit was yanked from its case and retrofitted with connectors to make it swappable for other units.

A little help goes a long way and [Rich] thanks his friend [Loftur, VE2LJX] for contributing numerous code improvements and feature additions which can be viewed in the repository. Check out the video below where these features are shown off.

In its present state the radio draws 80 mA at 12V in receive mode. It doesn’t transmit yet but we’ll keep our eyes open for another update on that. [Rich] plans to populate the input circuitry and write the transmit code next.

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Digitally Controlled Circuit Bending

Circuit bending doesn’t get a lot of respect around some parts of the Internet we frequent, but there is certainly an artistry to it. Case in point is the most incredible circuit bending we’ve ever seen. Yes, it’s soldering wires to seemingly random points on a PCB, but these bend points are digitally controlled, allowing a drum machine to transform between bent crunchiness and a classic 1980s drum machine with just a few presses of a touch screen controller.

All circuit bending must begin with an interesting piece of equipment and for this project, [Charles], the creator of this masterpiece of circuit bending, is using a Roland TR-626, a slightly more modern version of the TR-606, the percussive counterpart of the infamous TB-303. The circuit is bent in the classical fashion – tying signals on the PCB to ground, VCC, or other signals on the board. [Charles] then out does everyone else by connecting these wires to 384 analog switches controlled by an Arduino Mega. Also on the Arduino is a touch screen, and with a slick UI, this old drum machine can be bent digitally, no vast array of toggle switches required.

[Charles] has put up a few videos going over the construction, capabilities, and sound of this touch screen, circuit bent drum machine. It’s an amazing piece of work, and something that raises the bar for every circuit bending mod from this point on.

Thanks [oxygen_addiction] and [Kroaton] for sending this one in.

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Easier UART to 1-Wire Interface

The 1-Wire protocol is usually found in temperature sensors, but you’ll also find it in chips ranging from load sensors, a battery sensor and LED driver that is oddly yet officially called a ‘gas gauge’, and iButtons. It’s a protocol that has its niche, and there are a few interesting application notes for implementing the 1-wire protocol with a UART. Application notes are best practices, but [rawe] has figured out an even easier way to do this.

The standard way of reading 1-Wire sensors with a UART is to plop a pair of transistors and resistors on the Tx and Rx lines of the UART and connect them to the… one… wire on the 1-Wire device. [rawe]’s simplification of this is to get rid of the transistors and just plop a single 1N4148 diode in there.

This would of course be useless without the software to communicate with 1-Wire devices, and [rawe] has you covered there, too. There’s a small little command line tool that will talk to the usual 1-Wire temperature sensors. Both the circuit and the tool work with the most common USB to UART adapters.

Reverse Engineer then Drive LCD with FPGA

Fans of [Ben Heck] know that he has a soft spot for pinball machines and his projects that revolve around that topic tend to be pretty epic. This is a good example. At a trade show he saw an extra-wide format LCD screen which he thought would be perfect on a pinball build. He found out it’s a special module made for attaching to your car’s sun visor. The problem is that it only takes composite-in and he wanted higher quality video than that offers. The solution: reverse engineer the LCD protocol and implement it in an FPGA.

This project is a soup to nuts demonstration of replacing electronics drivers; the skill is certainly not limited to LCD modules. He starts by disassembling the hardware to find what look like differential signaling lines. With that in mind he hit the Internet looking for common video protocols which will help him figure out what he’s looking for. A four-channel oscilloscope sniffs the signal as the unit shows a blue screen with red words “NO SIGNAL”. That pattern is easy to spot since the pixels are mostly repeated except when red letters need to be displayed. Turns out the protocol is much like VGA with front porch, blanking, etc.

With copious notes about the timings [Ben] switches over to working with a Cyclone III FPGA to replace the screen’s stock controller. The product claims 800×234 resolution but when driving it using those parameters it doesn’t fill the entire screen. A bit more tweaking and he discovers the display actually has 1024×310 pixels. Bonus!

It’s going to take us a bit more study to figure out exactly how he boiled down the sniffed data to his single color-coded protocol sheet. But that’s half the fun! If you need a few more resources to understand how those signals work, check out one of our other favorite FPGA-LCD hacks.

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CAMdrive is an Open Source Time-lapse Photography Controller

[Nightflyer] has been working on an open source project he calls CAMdrive. CAMdrive is designed to be a multi-axis controller for time-lapse photography. It currently only supports a single axis, but he’s looking for help in order to expand the functionality.

You may already be familiar with the idea of time-lapse photography. The principal is that your camera takes a photo automatically at a set interval. An example may be once per minute. This can be a good way to get see gradual changes over a long period of time. While this is interesting in itself, time-lapse videos can often be made more interesting by having the camera move slightly each time a photo is taken. CAMdrive aims to aid in this process by providing a framework for building systems that can pan, tilt, and slide all automatically.

The system is broken out into separate nodes. All nodes can communicate with each other via a communication bus. Power is also distributed to each node along the bus, making wiring easier. The entire network can be controlled via Bluetooth as long as any one of the nodes on the bus include a Bluetooth module. Each node also includes a motor controller and corresponding motor. This can either be a stepper motor or DC motor.

The system can be controlled using an Android app. [Nightflyer’s] main limitation at the moment is with the app. He doesn’t have much experience programming apps for Android and he’s looking for help to push the project forward. It seems like a promising project for those photography geeks out there. Continue reading “CAMdrive is an Open Source Time-lapse Photography Controller”

Annoy Your Enemies with the Hassler Circuit

[Craig] recently built himself a version of the “hassler” circuit as a sort of homage to Bob Widlar. If you haven’t heard of Bob Widlar, he was a key person involved in making analog IC’s a reality. We’ve actually covered the topic in-depth in the past. The hassler circuit is a simple but ingenious office prank. The idea is that the circuit emits a very high frequency tone, but only when the noise level in the room reaches a certain threshold. If your coworkers become too noisy, they will suddenly notice a ringing in their ears. When they stop talking to identify the source, the noise goes away. The desired result is to get your coworkers to shut the hell up.

[Craig] couldn’t find any published schematics for the original circuit, but he managed to build his own version with discrete components and IC’s. Sound first enters the circuit via a small electret microphone. The signal is then amplified, half-wave rectified, and run through a low pass filter. The gain from the microphone is configurable via a trim pot. A capacitor converts the output into a flat DC voltage.

The signal then gets passed to a relaxation oscillator circuit. This circuit creates a signal whose output duty cycle is dependent on the input voltage. The higher the input voltage, the longer the duty cycle, and the lower the frequency. The resulting signal is sent to a small speaker for output. The speaker is also controlled by a Schmitt trigger. This prevents the speaker from being powered until the voltage reaches a certain threshold, thus saving energy. The whole circuit is soldered together dead bug style and mounted to a copper clad board.

When the room is quiet, the input voltage is low. The output frequency is high enough that it is out of the range of human hearing. As the room slowly gets louder, the voltage increases and the output frequency lowers. Eventually it reaches the outer limits of human hearing and people in the room take notice. The video below walks step by step through the circuit. Continue reading “Annoy Your Enemies with the Hassler Circuit”