DIY Head Mounted Display Based On Movie Based On Stephen King Story

Ever since [will1384] watched “The Lawnmower Man” as a wee lad, he’s been interested in virtual reality. He has been messing around with it for years and even had a VictorMaxx Stuntmaster, one of the first available head mounted displays. Years later, the Oculus Rift came out and [will1384] wanted to try it out but the $350 price tag put it just out of his price range for a discretionary purchase. He then did what most of us HaD readers would do, try building one himself, and with a goal for doing it for around $100.

The main display is a 7″ LCD with a resolution of 1024×600 pixels and has a mini HDMI input. Some DIY head mounted display projects out on the ‘web use ski goggles or some sort of elastic strap to hold the display to the wearer’s head. [will1384] took a more industrial approach, literally. He used the head mounting system from a welding helmet. This not only has an adjustable band but also has a top strap to prevent the entire contraption from sliding down. Three-dimensional parts were printed out to secure the LCD to the welding helmet parts while at the same time creating a duct to block out external light.

diyhmd-lenses

Inside the goggles are a pair of 5x Loupe lenses mounted between the user’s eyes and the LCD screen. These were made to be adjustable so that the wearer can dial them in for the most comfortable viewing experience. The remote mounted to the top strap may look a little out-of-place but it is actually being used to capture head movement. In addition to a standard wireless remote, it is also an air mouse with internal gyroscopes.

First Ever Poughkeepsie Mini Maker Faire

This past Saturday was the first Mini Maker Faire held in Poughkeepsie, NY. Although it was the first in the area, the event went extremely well having over 60 makers and countless attendees. It was held at the Poughkeepsie Day School and made use of a large percentage of the indoor area.

roboticarm

Ninth graders of the hosting school [Liam], [Johnson] and [Matt] were proudly displaying some of their projects. One of which was a robotic hand controlled by a glove the user wears. Flex sensors sewn into the glove detect how much each finger is bent. That information is read by an Arduino which then commands 5 independent servos to pull string ligaments to bend the fingers of the 3D printed robotic hand. The kids give credit to this Instructable which was the inspiration for their desire to build such a project.

No Maker Faire would be complete without some 3D printers. On hand was a father/son team that built a Mini Kossel. The design is simple and elegant, and apparently assembly is no problem for even the youngest maker. 3D printing guru [Ed] was on hand with his MakerGear M2 to show some practical uses for 3D printers. They are not just for making Yoda heads! [Ed] also gave a presentation on the matter, explaining why 3D printing is important and useful to people, even the common non-techno-nerd consumer.

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Self Balancing Vehicle Inspired By Bicycles Of Yesteryear

[XenonJohn] is not a newcomer to the world of self balancing vehicles. He was part of the Medicycle team and a semifinalist for The Hackaday Prize. Working on the Medicycle had exposed some opportunities for improvement of the design, the most significant being the single wide wheel supporting the vehicle and rider. The unicycle design was more difficult to learn to ride than that of a two-wheeled nature. [XenonJohn] wanted to make an improved self balancer and this new one will have two wheels that are independently controlled.

Although the finished product looks like it started with a bike frame, the self-balancer’s frame is actually completely custom. The handlebars and banana seat were purchased new as aftermarket parts for old-style bicycles. Powering the two wheels is a pair of 24v brushed motors, conveniently each one came with a 6:1 reduction gearbox pre-installed. The wheels are a complete compilation of parts not intended to go together. The BMX bike rims were laced to mountain bike front hubs. The hubs have provisions for a disk brake but [XenonJohn] mounted a large toothed pulley there instead. A belt then connects the drive motor gearboxes to the pulleys completing the drive train.

The LiFePO4 battery kit was purchased off eBay and puts out 24v and 15AH using eight cells. These batteries alone were a hefty percentage of the projects cost, costing nearly $300. Controlling the vehicle is an Arduino Mega that makes use of the FreeSix IMU library. The Mega receives inputs via I2C from a Sparkfun SEN-10121 board that contains both accelerometers and gyroscopes along with turn switches connected to the ‘brake’ levers on the handlebars. The Arduino then sends commands to the 25 amp Sabertooth motor controllers to keep you balanced as you buzz around town.

Video below.

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DIY Plotter Strives For Cheapest CNC Machine Title

Arguably, taking the plunge into the CNC hobby does indeed have potential to end up costing more than expected. But that should be no reason to deter anyone from doing it! [msassa11] shows us how to do it in full effect with his definitely unique and extremely inexpensive homemade plotter.

The design goal was to keep this machine as low-cost as possible while at the same time using materials that can be found around any tinkerer’s shop or at least purchased locally. First of all, you’ll notice that there is only one linear rail, yes, one rail for two axes of movement. The single rail was removed from an inkjet printer along with the mating bushing that originally allowed the print head to move freely back and forth. A threaded rod lead screw does double duty here, keeping the X axis carriage from rotating around the linear rail and also transmitting the force to move the carriage back and forth. Both the lead nut and bushings are held in place with cast-epoxy mounts.

uniquecnc-closeupAs unique as the X axis is, the Y sure gives it a run for its money. No linear rails are used, two lead screws are the only things that maintain the gantry’s position. To prevent gravity from pulling the gantry down and bending the Y axis lead screws, there are a couple of bearings on either side that ride along the bed of the machine. The frame material also hits the cheap target, it’s made from blank PCB board. A PIC16F877 microcontroller and a handful of mosfets control the motors. [msassa11] built this control circuit but admits it’s performance is not that great, it’s noisy and loses torque at high speed.

[msassa11] certainly proves that he is extremely resourceful with the outcome of this project. He met his goal of building an extremely inexpensive CNC machine. Check out his project page to see a ton of photos and find out what other unconventional ideas he used to build his machine.

Battery Shield Mounts Underneath The Arduino

So, what do you do when your Arduino project needs to operate in a remote area or as a portable device? There are LiPo battery shields available, and although they may work well, recharging requires access to a USB port. You can also go the 9v battery route plugged into the on-board regulator of the Arduino but the low mAh rating of a 9v won’t allow your project to stay running for very long. [AI] needed a quick-change battery option for his Arduino project and came up with what he is calling the AA Undershield.

As the name implies, AA sized batteries are used in the project, two of them actually. Yes, two AA batteries at 1.5v each would equal only 3 volts when connected in series. The Arduino needs 5v so [AI] decided to use a MAX756 DC-to-DC step-up regulator to maintain a steady stream of 5v. This article has some nice graphs showing the difference in performance between a 9v battery being stepped down to 5v verses two AA’s being bumped up to 5v.

The ‘under’ in Undershield comes from this shield being mounted underneath the Arduino, unlike every other shield on the planet. Doing so allows use of a standard 0.100″-spaced prototype PCB and is an easy DIY solution to that odd-sized space between the Arduino’s Digital 7 and 8 pins. The Arduino mounts to the Undershield via its normal mounting holes with the help of some aluminum stand offs.

[AI] did a great job documenting his build with schematics and lots of photos so that anyone that is interested in making one for themselves can do so with extreme ease.

DIY FPV Goggles Born From Necessity of Cheapness

So now that you’ve built your quadcopter and can fly it without crashing most of the time, what’s next? How about metaphorically hopping into the pilot’s seat with a First Person View setup. Great idea… but the cost of the required gear can be a deal breaker. FPV goggles alone range from the low to high hundreds. [sneaky] was using his laptop screen for his FPV setup and decided to try to make is own FPV goggles.

The display is just a small LCD screen that was purchased off eBay. Craft foam board was cut, bent, glued and duct taped to form a box about the same size as the LCD screen which is also secured to the box with duct tape. [sneaky] then cut the opposite side of the box to fit his face before he lined it with 1/2″ weatherstripping foam. Staring at an LCD screen just inches from your face is sure to cause some discomfort. A Fresnel lens inserted in between the user’s eyes and the LCD reduces eye strain to make long flights tolerable. The whole assembly is then held to your noggin via a recycled ski goggle strap.

In the end, [sneaky] likes his new goggles better than his old laptop screen and sun shade setup. The goggles aren’t too heavy and he can wear them comfortably for a while. We’ve seen a DIY FPV goggle setup in the past that uses individual lenses for each eye rather than one large Fresnel lens.

Water Softener Level Detector Keeps You Out Of Trouble With Wife

Some households have water supplies that contain higher than desired levels of minerals. This condition is called hard water. There is nothing harmful about hard water but it does leave mineral deposits on pipes and appliances and makes cleaning a little bit more difficult. The solution is to have a water softener system which is basically a tank filled with salt that the household water passes through. This tank has to be refilled about every month and [David] was catching a little flak from his wife because he kept forgetting to fill it. He then set out to do what any great husband would do and built a Water Softener Monitor that reports the quantity of salt in the basement tank up to the living quarters.

[David] started thinking that he should test the salinity of the water to determine if salt needed to be added but after thinking about it for a while decided against it because any metal in that salty water would surely corrode. A non-contact approach would be to use an IR distance sensor mounted to the top of the tank and measure the distance to the pile of salt that slowly lowers as it dissolves into the water. In this case, he used a Sharp GP2D12 that can measure accurately from 10 to 80cm.

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