I remember I used to have a magic 8 ball key-chain as a kid. I loved asking it the stupidest questions and seeing it magically divine the answer. Either that or it just repeatedly responded with an anti-climatic ask again later. One day the magic just dried up … literally, the purple fluid in the cavity evaporated! Randomly remembering this device, I decided on the spur of the moment, after learning how to seed and use the rand() function in the standard c library, to make my very own digital magic 8 ball (which would be impervious to drying up, but still vulnerable to releasing its magic smoke).
Digital Magic 8 Ball - [Link]
It is one thing to put together LEDs, a few logic chips and a CPU to make something interesting. But, it is a completely different story to connect cables to your creation and try to run various low- and high-frequency signals through them. I’m saying this not to denigrate, but the laws of physics are relentless and good cabling is an area of expertise all for and by itself.
My first encounter with the practicalities of cabling came some 20 years ago when I tried to run a 8MHz digital CGA video signal through 15..25m cables. As you can imagine, my first try did not succeed. I had learned about transmission lines almost 10 years earlier, but never had used it in practice. So, I had to read up on it and understand the problem.
The theory behind transmission lines is well understood, but can be daunting if not versed in the world of analogue electronics. Just know, there is no way you can wiggle your way out of a transmission line’s path. You will encounter them at some stage in your hacking and then you need to solve your problem.
Luckily, there are a few relatively simple things you can do to save yourself from defeat. The problems that transmission lines introduce can be visualized reasonably easy, and, with a lot of pictures, I will try to show you what happens to signals of various frequency and with different transmission line connections.
Transmission Lines and Cabling – Sending Bits Down a Wire - [Link]
Go Free Range build outstanding software for the web.. lazyatom writes – [via]
We’ve built an open-source distributed software system for making it simple to produce really great looking content on little printers like that in the IoT printer kit. Take a look here: http://gofreerange.com/printer. I strongly suspect that it would be trivial to get this working with the IoT kit itself. Anyone fancy giving it a go?
Hello printer open-source distributed software system - [Link]
Hello Limor and staff,
Long time Adafruit customer here; I really liked your presentation at the Open Source Hardware Summit where you talked about why people should do open source hardware projects.
I’m reaching out to you for help in publicizing my project, OpenBeam. I feel that there is a genuine demand for an extrusion that is stiffer than MicroRax /but still smaller than an 80/20 extrusion, and I don’t think the 80/20 prices are reasonable for hobbyist use with the cost of their speciality fasteners. I’ve also been very frustrated at the technical flaws in Makerbeam’s fasteners (that to my knowledge, is still uncorrected after 2 years), the lack of project progress, and their availability.
I’ve worked very hard to engineer OpenBeam to have all the features of 80/20 (including the hole for edge tapping), being able to price-match against MicroRAX even though MicroRAX has 1/3 the material as OpenBeam, and still have enough margin to sustain this as a business. So far, everyone at the local hackerspace that’s played with the prototype extrusions likes what they see.
4 days into the 30 day funding campaign, we managed to raised 1/6 of the goal. As we approach “The Trench” in the funding cycle, it is crucial to try to keep the interest level up.
Will you be so kind to mention this project in your blog posts
OpenBeam – An open source miniature construction system by Terence Tam? - [Link]
I have been dreaming about having a 3D Printer at home for many years, but the ones with good quality are not affordable and the low costs just deliver poor quality. Sounds crazy but I decided to build a high resolution 3D Printer by myself at home (people actually said that I was crazy and this was impossible). The funny thing I never saw this type of machines in real life, and still haven’t seen one besides the one I built.
Now that I succeed building the first prototype, the target is to bring this low cost 3D Printer to every home, so we are developing the first affordable one with high resolution. I hope you enjoy our blog, follow us and you can have this printer in your home soon.
Resin-based 3D Printer kit - [Link]
Flylogic is known for their skills in reverse engineering chips. They were familiar with Atmel smartcards AT90SC3232 and AT90SC3232C and assumed that the AT90SC3232CS was similar but with an extra IO pad. They discovered the AT90SC3232CS is a completely new design based on the larger AT90SC6464C device,
Get all the fascinating details on the exploration of this smartcard and images at Flylogic’s Analytical Blog.
Atmel AT90SC3232CS smartcard destruction - [Link]
I’ve blogged previously about the development process for my latest project, an artificial die designed for die-based Role Playing Games. When I started this project, I had several design goals in mind: I wanted it to be extremely small and easy to carry, yet have 6 buttons to “roll” each of the standard sizes of die (D4, D6, D8, D10, D12, and D20). I also wanted it to based on a Random Number Generator (RNG) implemented in hardware instead of using the built in pseudo-random number generator. As those who have been watching the Show And Tell will know, I’m proud to say that I’ve succeeded. If you’d like to see it in action, a short demo video is available here..
A New Electronic Die - [Link]
This simple circuit that converts a 5V PWM signal into a variable precision reference voltage with a rang of -2.5V to +2.5V. Many designs, like a digitally controlled power supply, programmable dummy load, etc, require a Digital to Analog Converter to supply a stable reference votlage. [via]
The circuit described here uses the ubiquitous LM431 shunt regulator to implement a second-order Sallen-Key low pass filter together with a level shifter (see the figure). Compared to the traditional approach, it provides a far sharper roll-off along with a low-impedance output, bipolar output. It will produce a –2.5- to +2.5-V output with a 0- to 5-V PWM signal input. The value of Vout is equal to (5 V × dc) – 2.5 V, where dc is the PWM duty from 0.0 to 1.0 (0% to 100%)
Digitally adjustable precision reference driven via PWM - [Link]
Horto domi is an open hardware raised-bed garden unit with environmental control and monitoring via web-interface thanks to Arduino Ethernet. DIY sensors, such as those collecting moisture and temperature data help monitor the environment within the dome and will eventually be used to automate conditions. The goal is to grow whatever you want, whenever you want, wherever you are. Horto domi is Latin for ‘Garden at home.’ It’s a statement to healthful food independence, a “neo-renaissance” tip of the hat to Arduino, and it sounds like horticultural dome. Particular consideration was taken in this prototype’s design to maximize the mineral and nutrient value of the beyond-organic produce and minimize environmental contamination risks.
Horto domi: the Open Garden - [Link]
Viktor made a sound trigger for his DSLR camera:
Now that I can take pictures of lightning I decided that I also want to be able to trigger my camera with sound.
An op-amp filters and amplifies a microphone signal. The output is fed to a PIC microcontroller that triggers the flash when the sound reaches a certain level. The trigger sound level and shutter delay are set with a pot. [via]
Lil Bang – Sound trigger for cameras - [Link]