How to Make a Custom LCD from Scratch

If you have ever wondered what it took to make your own custom graphic LCD from scratch, this video from [Applied Science] is worth a watch. It’s concise and to the point, while still telling you what you need to know should you be interested in rolling your own. There is also a related video which goes into much more detail about experimenting with LCD technology.

[Applied Science] used microscope slides and parts purchased online to make an LCD that displays a custom graphic when activated. The only step that home experimenters might have trouble following is coating the glass slides with a clear conductive layer, which in the video is done via a process called sputtering to deposit a thin film. You don’t need to do this yourself, though. Pre-coated glass is readily available online. (Search for Indium-Tin Oxide or ‘ITO’ coated glass.)

The LCD consists of a layer of liquid crystal suspended between two layers of conductive glass. An electrical field is used to change the orientation of crystals in the suspension, which modulate the light passing through them. Polarizing filters result in a sharp contrast and therefore a visible image. To show a particular shape, some of the conductive coating is removed from one of the layers in the shape of the desired image. The process [Applied Science] uses to do this is nearly identical to etching a custom PCB. Continue reading “How to Make a Custom LCD from Scratch”

[HomoFaciens] Shows Off With DIY Paper Printer

[HomoFaciens] is always making us feel silly about our purchases. Did we really need to buy a nice set of stepper motors for that automation project? Couldn’t we have just used some epoxy and a threaded rod to make an encoder? Did we need to spend hours reading through the documentation for an industrial inkjet head? Couldn’t we just have asked ourselves, “What would [HomoFaciens] do?” and then made a jailhouse tattoo gun attached to a broken printer carriage and some other household tech trash?

In his continuing work for his Hackaday prize entry, which we have covered before, his latest is a ink (…drop? ) printer. We think the goal is a Gingery book for CNC.  He begins to combine all his previous work into a complete assembly. The video, viewable after the break, starts by explaining the function of a salvaged printer carriage. A motor attached to a belt moves the carriage back and forth; the original linear encoder from the printer is used for positional feedback.

The base of the printer is a homemade y-carriage with another salvaged printer motor and encoder driving a threaded rod. The positional feedback for this axis is provided by a optical mouse gliding on a sheet of graph paper.  The printer nozzle is a cup of ink with a solenoid actuated needle in it. When the needle moves in a hole at the bottom, it dispenses ink.

As always, [HomoFaciens] makes something that is the very definition of a hack. Commenters will have to go elsewhere to leave their favorite debasement.

Continue reading “[HomoFaciens] Shows Off With DIY Paper Printer”

From Rusty Cargo Van to Mobile Studio

Looking for a more unique living experience, [Zach Both] converted a 2003 Chevy Express Van he picked up from Craigslist into a gorgeous mobile home.

The van had 200,000 miles when he bought it. The body and frame were a bit rusty, but he saw the potential. First step was gutting the entire van, and getting rid of any surface rust with an angle grinder. It was a long and tedious process, but once it was done he had a blank slate to work with. Continue reading “From Rusty Cargo Van to Mobile Studio”

This DLP 3D Printer Build Is Going Really Well

We suppose [Dan Beaven] got up one day and said, “I’ll make my own resin 3D printer, with resin management and an advanced separation mechanism!” It’s a build log that shows just how possible it is to roll your own resin printer.

Prints on a dime!
Prints on a dime!

The machine isn’t finished yet, but the example prints coming off it are already very impressive. [Dan] stopped the print midway to get this photo of the detail on the stairs in the standard rook torture test.

[Dan] wants a lot of features from his machine that some of the more polished commercial printers are only now offering. One really nice one is the sliding and twist separation instead of tilt. This will allow for cleaner separation between layers during a print, a lower failure rate, and also faster print times.

He also added resin management with a peristaltic pump. This reduces the size of the build vat, and less resin will be exposed to the elements and wasted. It also means that the printer can run unattended. In the resin handling area of the printer he’s also added a carbon air filter. This lets him run higher performing resins without gassing him out of house and home with fumes.

We like how [Dan] just runs right ahead and puts the printer together. He even points out kludges on the machine that are holding it together long enough for him to print a more functional part for the 3D printer– on the 3D printer. We look forward to the next installment.

Learning ARM Without Dev Board

There’s a tremendous amount of value in using pre-built, known-good development environments. It saves you hours of potential headaches when things aren’t working. Is the bug in the hardware or the software? If you bought a dev kit, you can be pretty sure it’s your software. But sometimes using a dev kit also feels like there’s a black box in the system. [Kevin] wanted to peer inside the black box, so he ordered a tray of cheap STM32F103 chips on eBay, and did the rest himself.

“The rest” isn’t all that much, but figuring that out is half the battle. [Kevin] soldered the TQFP chip onto a breakout board, added some decoupling capacitors, and connected four pins up to a dirt-cheap ST-Link programmer clone. The rest of the article describes the toolchain he used to compile for and program the chip. The end result is, natch, a blinking LED.

If you’re a bit experienced with microcontrollers and want to dive head-first into an ARM chip, [Kevin]’s writeup is just the ticket. In a single (long) blog post, he walks you through all the steps. If this is your first rodeo, you might be tempted to cheese out and buy a pre-built board on eBay (search “STM32F103” and you’ll find many options to choose from) and we don’t think that’s a bad idea either. Still, there’s just something to be said for the confidence that you’ll have once you’ve built the whole system from scratch.

How Does a Buck Converter Work Anyway?

[Great Scott] should win an award for quickest explanation of a buck converter. Clocking in at five and a half minutes, the video clearly shows the operating principles behind the device.

It starts off with the question, what should you do if you want to drop a voltage? Many of us know that we can dim and brighten an LED using the PWM on an Arduino, but a closer inspection with an oscilloscope still shows 5V peaks that would be dangerous to a 3.3V circuit. He then adds an inductor and diode, this keeps the current from dropping too fast, but the PWM just isn’t switching fast enough to keep the coil energized.

A small modification to the Arduino’s code, and the PWM frequency is now in the kHz range. The voltage looks pretty good on the oscilloscope, but a filter cap gets it to look nice and smooth. Lastly, he shows how when the load changes the voltage out looks different. To fix this a voltage divider feeds back the information to the Arduino, letting it change the PWM duty to match the load.

In the last minute of the video he shows how to hook up off-the-shelf switching regulators, whose support components are now completely demystified as the basic principles are understood. Video after the break.

Continue reading “How Does a Buck Converter Work Anyway?”

Feeding The Cat, Reinventing the Wheel

There are few projects that we see as many iterations of as the pet feeder or the plant waterer. (What is it with you people? Are you all as forgetful as we are?) Still, the fun is in the details of the implementation. Or at least that’s the case with [Emmaanuel]’s cat feeder.

The writeup is split into three parts: the worm-drive, the electronics, and the housing (here in English: worm, electronics, housing). And of course, there’s a video inlined below.

The auger and motor housing make great use of PVC pipe and 3D printing, and the dispenser unit looks quite professional. There’s not all that much to say about the electronics — an Arduino clone, an LCD, and a cheap gear motor do just about what you’d expect.

The CNC’ed case with spring-fit tabs steals the show, however. It’s made out of MDF, which doesn’t take well to screwing or glueing. With carefully routed pins and tabs that have a little spring in them, [Emmaanuel] was able to take the pieces off the mill table and just snap them together. Awesome.

Continue reading “Feeding The Cat, Reinventing the Wheel”