Bipedal walking sentinel project

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A bipedal walking robot by Ye Guan:

The robot will have a complete compliment of sensors to help it understand its surrounding and its own condition. The current design uses a total of seven sensors.  For external obstacle avoidance there is a sonar sensor to detect long range surroundings, and an inferred distance sensor pointed down to detect the surface conditions for the robot’s next step. The sonar will allow the robot to detect and walk around large obstacles while the inferred sensor allows the robot to accommodate for changing road conditions, such as stairs. Two pressure sensors will be built into each foot to detect when the foot is on the ground. A gyroscope/accelerometer will be mounted in the head of the robot to inform the robot changes in its orientation and balance so it can adjust itself before falling. A photo detectors will tell the robot to turn on its head lights when there is a lack of ambient lighting. Finally temperature sensors will be added to make sure the system do not overheat, especially with the batteries and microcontrollers in such close proximity due to the space constraints. The entire system will be controlled through a Arduino Mega 2560 microcontroller mounted in the robot’s head.

 

 

Via Hacked Gadgets.

Fruit machine, 7-segment one-armed bandit

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Bertho  shared his fruit machine, a 7-segment one-armed bandit in the project log forum:

I was revisiting the first program I ever wrote and decided it was time to redo the project with “modern” micro tech. The Fruit Machine is a One-armed Bandit (slot-machine) implemented with 7-segment displays. It has 4 displays to represent the “reels” and two for the credits.
The reels can be held in place after a roll to increase the chances of a win. A winning combination are three or four equal symbols in a row (or two ‘o’ on the right). A “bonus” feature lets you wager double.
The hardware is a simple AVR processor with 7-segment displays in a matrix. Nothing breathtaking or complex.

Via the forum.

Check out the video after the break. Continue reading “Fruit machine, 7-segment one-armed bandit”

Control a camera flash using TTL signals

Control a camera flash using TTL signals by Hemal Chevli

So finally bought a new flash, and powered up, I used one of my keys to shot the pin and base plate and IT WORKED! Next I measured the voltage between centre pin and base pin, it was 5V. Things were simple from this point, pulled out and opto isolator, connected the led side to uC and transistor side to the centre pin and base plate. On your arduino you can wire pin 13 to the opto-isolator and upload the blink sketch to fire the flash instead of LED . I had to hot glue the wires on the base plate. With the TTL input you can pretty much do anything to control it, perhaps use a 555 for periodic flashes, may be use for your next water drop photography.

Analysing 433 Mhz transmitters with RTL-SDR

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Yashin has posted this tutorial at ArcanumX demonstrating how to read and decode 433 MHz digital data transmissions. “I intend to demonstrate how the RTL-SDR can be used to sniff 433 Mhz transmitters. These are pretty cheap and can be found in a lot of appliances including alarm sensors. This post is also intended to be an intro to RTL-SDR usage. I suggest you get Kali linux (1.0.6>) on your system as it has most of the dependencies required for this demo.”

The technique involves receiving the signal using an RTL-SDR dongle which feeds into a GNU Radio program. GNU Radio extracts the signal to a wave file which can then be analyzed using rtl_433 software. Yashin gives a good explanation here on exactly how to use GNU Radio to capture these signals, detailing the proper (though easily overlooked) way to terminate the recording of a wave file.

ATXMega Primer

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Shawon Shahryiar over at Embedded Lab talks about Atmel XMega in this tutorial:

At present we have different families of XMega devices. Of these many we are focused toward the AU series only throughout this post and its following ones. I’ll explain later why I’m interested in this series. This is the first post of a series of posts that I’ll be publishing time-to-time. Well I should admit that making tutorial notes is not my favourite hobby but it helps me to keep documentations for future uses, reference, etc. and at the same time help others to get an easy access that I have crossed with lot of difficulties.

 

Mini LCD adapter Backpack

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Arthur Guy made this mini LCD backpack for the smaller display screens:

This is an LCD backpack but it is for the smaller displays with the double row of pins rather than the single line.
I made this adapter as I was working with some small displays and needed a simple way of connecting it to a microcontroller. There are plenty of adapters for the standard single row displays but I couldn’t find any for the smaller dual row displays
This adapter works with existing libraries built around the PCF8754 shift register

This project is now available on Tindie.

Cheap battery-powered micro-controller projects

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An article on cheap battery-powered micro-controller projects by Nerd Ralph:

Once the higher cost of a 9V battery is factored in (about $1.50), the 9V battery is clearly more expensive than a 3V coin cell. However you may have a cheap source of 9V batteries – smoke detectors. I’ve found my smoke detectors start beeping to replace the batteries when the open-circuit voltage is still above 8V.
I’ve re-used these batteries for RF transmitter projects. The transmitter modules I use will work with 3-12V, with more voltage providing higher power transmission. Instead of using a voltage regulator to power the AVR, I use a LED similar to what I did for my ATtiny85 NRF24l01+ project. Instead of a red LED, I used a green LED with a forward voltage of 3V. With the 9V battery putting out 7.9V under load, I measured 4.9V at the input of an ATtiny84a I used. Besides being a bit cheaper than a regulator, the LED has the benefit of working as a power use indicator – when the AVR is consuming more power the LED glows brighter.

 

Andy Green’s 1,000mph office revealed

This video from Bloodhound SSC explains how they design and build an 1000mph office:

BLOODHOUND Driver Andy Green takes you on a tour of the cockpit.
The state-of-the-art carbon fibre monocoque has been tailored to the needs of driver Andy Green and will be his supersonic office during record attempts in the South African desert in 2015 and 2016.

Hack adds Bluetooth control to old iPod using Android and Arduino


The crew at Erroneous Data presents this tutorial detailing how to wirelessly control an old iPod music player with you Android device. Using only an Arduino, an HC-05 Bluetooth module and a few resistors they show how to build your very own MuseHack. The project includes the Arduino code as well as the Android app which lets you control the iPod remotely via Bluetooth.

#FreePCB via Twitter to 2 random RTs

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Every Tuesday we give away two coupons for the free PCB drawer via Twitter. This post was announced on Twitter, and in 24 hours we’ll send coupon codes to two random retweeters. Don’t forget there’s free PCBs three times a every week:

  • Hate Twitter and Facebook? Free PCB Sunday is the classic PCB giveaway. Catch it every Sunday, right here on the blog
  • Tweet-a-PCB Tuesday. Follow us and get boards in 144 characters or less
  • Facebook PCB Friday. Free PCBs will be your friend for the weekend

Some stuff:

  • Yes, we’ll mail it anywhere in the world!
  • Check out how we mail PCBs worldwide video.
  • We’ll contact you via Twitter with a coupon code for the PCB drawer.
  • Limit one PCB per address per month please.
  • Like everything else on this site, PCBs are offered without warranty.

We try to stagger free PCB posts so every time zone has a chance to participate, but the best way to see it first is to subscribe to the RSS feed, follow us on Twitter, or like us on Facebook.

Yet another DIY diode laser engraver

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John1a wrote this Instructable detailing the build of his DIY diode laser engraver:

Only recently I got comfortable with the parts and knowledge needed to built a CNC. I really needed a kind of plotter for my work. As you know a Commercial Laser Engraver is really pricey and a good one is simply out of reach…
To make a long story short I decided to build my own… The funny part is that when I started designing I didn’t know Instructables so I reinvented the wheel in many cases…
So here we go: my Moving Gantry Arduino-Less Laser Engraver…

 

Analog synth project

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MikelRoi over at DorkbotPDX writes:

Here is a  pix of my synth project. The top panel has artwork that will get applied to the panel. Lots of holes drilled…whew! Below is the bottom panel with applied artwork and holes ready for mounting controls! I spent many hours getting the artwork right. That would dictate where the holes would go and allow for spacing of the pots and switches and to get it all to fit on the panel size I had.

DIY fingerprint scanning garage door opener

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Nodcah made this Instructables detailing the build of his DIY fingerprint scanning garage door opener:

As a person without a car, I don’t need to carry keys around everywhere I go. Because of this, I’ve been locked out of my own house several times. It’s a pain to wait for someone with a key, so I thought I would do something about it.

This project is my way of solving this problem, while getting the chance to interface with an awesome fingerprint scanner (aka: FPS).
Also, this module isn’t restricted to just garage doors, for you can create different kinds of simple motorized locks to suit your needs.

Continue reading “DIY fingerprint scanning garage door opener”

Bus Pirate v3.8 free PCB build

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MrMobileWill  blogged about his free Bus Pirate v3.8 PCB build.  The Bus Pirate is an open source hacker multi-tool that talks to electronic stuff.

If you build a free PCB we’ll send you another one! Blog about it, post a picture on Flicker, whatever – we’ll send you a coupon code for the free PCB drawer.

Get your own handy Bus Pirate for $30, including world-wide shipping. Also available from our friendly distributors.

App note: NXP Smartphone Quick-Jack Solution

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An interesting app note (PDF) from NXP where you can interface your mobile phone with a microcontroller via the audio 3.5mm jack.

Inspired by the University of Michigan’s Project HiJack, the NXP Smartphone Quick-Jack Solution repurposes the standard 3.5mm stereo audio jack found on most smartphones into a self-powered data channel that makes communication with these smartphones as easy as plugging a headset jack into the audio port.
The Quick-Jack demo board integrates a joystick, temperature sensor, LEDs and an expansion header. The app running on the smartphone is able to interface with these on-board peripherals via the Quick-Jack interface.

Free PCB Sunday: Pick your PCB

 

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We go through a lot of prototype PCBs, and end up with lots of extras that we’ll never use. Every Sunday we give away a few PCBs from one of our past or future projects, or a related prototype. Our PCBs are made through Seeed Studio’s Fusion board service. This week two random commenters will get a coupon code for the free PCB drawer tomorrow morning. Pick your own PCB. You get unlimited free PCBs now – finish one and we’ll send you another! Don’t forget there’s free PCBs three times every week:

Continue reading “Free PCB Sunday: Pick your PCB”

App note: Sending I2C-bus signals via long communications cables

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Extend I2C communication distance with this app note (PDF) from NXP.

Reliable I2C-bus communication at high data rates, and over many meters, can be achieved using widely available twisted- pair communication cable (e.g. Category 5e and similar 4-pair cables, as typically used for Ethernet communications).
The two bidirectional I2C-bus signals, SDA and SCL, are split into four unidirectional signals using P82B96 or PCA9600. Each signal is then transmitted over a separate twisted pair within the communication cable and combined again by another P82B96.

ZaCon badge development log


ZaCon is a community driven infosec conference held at the Kingsway Campus of the University of Johannesburg, South Africa. Andrew Nohawk developed the ZaCon V badge using an Arduino and RF components. He provides a detailed chronicle of his design and development process in this post. He explains, “For ZaCon V I built some electronic badges for the conference that are based on an Arduino framework (at least using an ATMega328 with an Arduino Bootloader) and communicate to each other via 433Mhz RF (the same that is used in remotes). The idea with the badges was to have a way to see who was interacting with whom and show it in a visual representation. Additionally I needed the badges to be cheap as.. well… I am cheap!

The badges took about 3 months to go from breadboard to finished and a large majority of that time was spent learning how electronics work (and don’t!). This however was not my first attempt at building badges, for the last 3 years I have built a design on a breadboard and then basically done nothing with it (apart from make a shaky cam video at 3am and suggest the idea).”

Part 2 can be found here.

App note: An overview of DMX512A

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An overview of (Digital Multiplex) DMX512A (PDF!) from Microchip:

This application note presents an overview of
DMX512A. It shows and explains the recommended
electrical and electronic requirements, then presents
how the protocol was implemented in the Microchip
Technology DMX512 Library. Included is a discussion
on using the back-channel capabilities.
DMX512 is the most common lighting communications
protocol used in theatrical lighting, and is often found in
architectural and other lighting systems. It was created
in 1986 by the United States Institute for Theatrical
Technology (USITT) to be a more reliable replacement
for the 0 to 10V standard, which was commonly used at
the time.