Whiteboard Clock Draws the Time

[Maurice] recently built a clock that draws the time (Google Doc) on a white board. We’ve seen plenty of clock hacks in the past, and even a very similar one. It’s always fun to see the different creative solutions people can come up with to solve the same problem.

This device runs on a PIC16F1454 microcontroller. The code for the project is available on GitHub. The micro is also connected to a 433MHz receiver. This allows a PC to keep track of the time, instead of having to include a real-time clock in the circuit. The USB connector is only used for power. All of the mounting pieces were designed in OpenSCAD and printed on a 3D printer. Two servos control the drawing arms. A third servo can raise and lower the marker to the whiteboard. This also has the added benefit of being able to place the marker tip inside of an eraser head. That way the same two servos can also erase the writing.

The communication protocol for this systems is interesting. The transmitter shows up on [Maurice’s] PC as a modem. All he needs to do to update the time is “echo 12:00 > /dev/whiteboard”. In this case, the command is run by a cron job every 5 minutes. This makes it easy to tweak the rate at which the time updates on the whiteboard. All communication is done one-way. The drawing circuit will verify the checksum each time it receives a message. If the check fails, the circuit simply waits for another message. The computer transmits the message multiple times, just in case there is a problem during transmission.

CNC Milling Photos with a Halftone Generator

Looking for an awesome way to mill out a photo or graphic? Check out [Matt Venn]’s halftone gcode generator which creates halftone CNC toolpaths from any image file. We’ve run across some halftone generators before, but [Matt]’s generator has some interesting features and makes for some pretty unique output.

[Matt] initially wrote a simple command line program in Python, but just rewrote his script with a more user-friendly UI that renders a preview of the output as you change options.  The UI lets you change parameters like drill depth, number of lines, and the step size to tweak the output. It even has an option to map the halftone points along a sine wave which makes an interesting effect as shown in the image above.

[Matt]’s program generates standard gcode that you can use to run your CNC machine. [Matt] recommends milling a material with layers of different colors, but you can always mill a solid material and fill the routed areas with paint or dye instead. Want to grab the script or check out the source code? Head over to [Matt]’s GitHub repository.

Thanks for the tip, [Keith O].

TwinTeeth: The Delta Bot PCB Factory

There are a few all-in-one CNC/milling/plotting/3D printing/engraving bots out there that claim to be mini factories for hobbyists, prototypers, and other homebrew creators. The latest is Diyouware’s TwinTeeth, a bot obviously inspired by a few 3D printers, but something that has a few interesting features we hope will propagate through the open hardware ecosystem.

The design of the TwinTeeth is an inverse delta bot, kinematically similar to a large number of 3D printers out there. Instead of suspending the tool from a trio of arms, the TwinTeeth puts the work surface on the arms and suspends the tool from the top of the machine. There are a few neat bonuses for this setup – all the tools, from a BluRay laser diode, a Dremel, solder paste dispenser, and a plastic extruder for 3D printing can be mounted in easy to mount adapters. The TwinTooth design uses three locking pins to keep each toolhead in place, and after a little bit of software setup this machine can quickly switch between its various functions.

One very interesting feature of this bot is the ability to mask off PCBs for chemical etching with a BluRay laser diode. This actually works pretty well, as evidenced by the teams earlier work with a purpose-built PCB masker machine. The only problem with this technique is that presensitized boards must be used. If that’s an issue, no problem, just use the Dremel attachment with a v-bit cutter.

Nordic NRF24L01+ – Real vs Fake

[zeptobars], the folks behind all the decapping hard work and amazing die shots are at it again. This time they decided to look under the hood of two identical looking Nordic nRF24L01+ chips.

The nRF24L01+ is a highly integrated, ultra low power (ULP) 2Mbps RF transceiver IC for the 2.4GHz ISM (Industrial, Scientific and Medical) band. Popular, widely used and inexpensive – and the counterfeit foundries are drawn to it like honey bees to nectar. But to replicate and make it cheaper than the original, one needs to cut several corners. In this case, the fakes use 350nm technology, compared to 250nm in the original and have a larger die size too.

These differences mean the fakes likely have higher power usage and lower sensitivities, even though they are functionally identical. The foundry could have marked these devices as Si24R1, which is compatible with the nRF24L01 and no one would have been wiser. But the lure of higher profits was obviously too tempting. A look through Hackaday archives will dig up several posts about the work done by [zeptobars] in identifying fake semiconductors.

In Chicago? Bring A Hack!

It’s been far too long since we’ve had a Hackaday presence at a hackerspace. This, of course, is a terrible oversight and something must be done to correct it. If you’re in Chicago, you’re in luck. We’re going to be at Pumping Station: One this Wednesday for a Bring-A-Hack meetup.

If you have a cool build to show off, a bunch of blinky things, wearables, or just some cool tech, the mythical Hackaday Prize guru [Sophi Kravitz] will be at PS:1 Wednesday evening. I’m pretty sure there will be stickers, but sadly no t-shirt cannon just yet.

The event is free, open to everyone, and there’s pizza. RSVPing would be a good idea, and you can do that over on the meetup.com page for the event.

Making a Homemade Stephen Hawking

It isn’t easy communicating when you have any form of speech impairment. In such cases, a Speech-generating device (SGD) becomes essential to help you talk to the world. When coupled with other ailments that limit body movement, the problem becomes worse. How do you type on a keyboard when you can’t move your hands, and how do you talk when your voice box doesn’t work. Well known Scientist Stephen Hawking has been battling this since 1985. Back then, it took a lot of hardware to build a text entry interface and a text to speech device allowing him to communicate.

But [Marquis de Geek] did a quick hack using just a few parts to make a Voice Box that sounds like Stephen Hawking. Using an arcade push button to act as a single button keyboard, an Arduino, a 74HC595 shift register, a 2-line LCD, and the SP0256 hooked to an audio amplifier / speaker, he built the stand-alone speech synthesizer which sounds just like the voice box that  Stephen Hawking uses. Although Dr. Hawking’s speech hardware is quite complex, [Marquis de Geek]’s hack shows that it’s possible to have similar results using off the shelf parts for a low cost solution.

There aren’t a lot of those SP0256-AL2 chips around. We found just a couple of retailers with small stock levels, so if you want to make one of these voice boxes, better grab those chips while they last. The character entry is not quick, requiring several button presses to get to the character you want to select. But it makes things easier for someone who cannot move their hands or use all fingers. A lot of kids grew up using Speak and Spell, but the hardware inside that box wasn’t the easiest to hack into. For a demo of [Marquis de Geek]’s homemade Hawking voice box, check the video below.

Continue reading “Making a Homemade Stephen Hawking”

Another Garage Door Opener, This Time With Security

We’ve been seeing a lot of garage door opener hacks, whether it’s because one person inspired everyone else to build their own Internet-connected GDO or because there’s something in the water that’s caused the simultaneous building of one specific type of project, we’re not sure. However, the latest one we’ve seen adds a little something extra: motion-based security.

[DeckerEgo] really went all out with this one, too. The core of the project is a Raspberry Pi hardwired to a universal garage door remote. The Pi also handles a small webcam and runs a program called motion, which is a Linux program that allows for all kinds of webcam fun including motion detection. While the other builds we see usually use a button or limit switch to tell whether the door is open or closed, this one just watches the door with the webcam so [DeckerEgo] can actually see what’s going on in the garage. As a bonus, the motion software can be configured to alert him if anything suspicious is going on in the garage.

The build is full-featured as well, with an interesting user interface overlaid on the live picture of the garage door. According to [DeckerEgo] the camera is a necessity because he wouldn’t trust a simple status indicator, but if you wanted to try one of those before breaking out the Raspberry Pi, we’ve featured one recently that you can check out.