Sunday, May 26, 2013

Pinhole Parallax!!!! (Cardboard + construction paper + lcd + matlab = multi-perspective display)

What separates a 2d image from a 3d image? We only see the world in 2d dimensions, so how do we know the difference between 2d and 3d. Our eyes observe objects from two different perspectives, each eye getting its own image. Furthermore, when you move your head, you experience parallax. In order to recreate this experience using an LCD monitor, each observer must see a different image. One way of doing this is to do the reverse of a pinhole camera and show each observer a different image. This project was my first (crude) step in exploring this area.

The first version of this display is a whopping 6 pixels by 6 pixels. Perfect for watching Iron Man in HD. The restriction in resolution is due to imperfections in the alignment of the holes in the filter, the low-light intensity by the LCD backlight, and the low pixel density of the LCD.

Improving any (or all of these) would allow for more resolution in the screen.My goal is to eventually make a 240x320 version that can handle up to 36 independent views (6 lateral, 6 vertical). I'm still a far way off. The filter is made by putting evenly spaced holes (using graph paper as a guide) into black construction paper. This is placed over a cardboard box which situates the filter a fixed distance from the LCD. Here's a video of the display in action:

Tuesday, February 5, 2013

Pillow Pal

Introducing PillowPal!

Ever had trouble waking up in the morning? Ever unconsciously turned off your own alarms?

Never have this problem again with PillowPal! Your friends now have complete control over when you wake up. Isn't that great? PillowPal allows your facebook friends to access your pillow online and turn on lights and music to wake you up in the morning.

PillowPal is an attachment for your phone. It communicates with your phone through the audio port, so it works with almost every phone. The brains of the pillow are a picaxe microcontroller and a set of 32 RGB addressable LED's which will blink different colors when its time to wake up.

This hack was made by Jesika Haria, Prabhav Jain, and Geza Kovacs for HackMIT. We made it to the finals! But didn't win :(

You can see our demo below:

Wednesday, October 31, 2012

Immersion Project

Immersion Project:

Imagine diving into another world without ever having to leave your desk. The immersion project turns your computer into a window to another world. You can now interact with google streetview panoramas by moving your head. This website uses the newest features of HTML5 and javascript head-tracking libraries to provide you an amazing experience using just your webcam for input. 

Try the demo using google chrome at:

Head-tracking made possible using code from MTSCHIRS

Wrist Wave

Wrist-Wave: Next-level clothing accessories
When you hear music, your foot starts tapping. What if your clothes interacted with the music around you! The wrist-wave is a battery operated wearable LED display which changes patterns according to the music around you! Great for dance clubs! 

Technical details: 
  • 32 RGB LED (from addressable LED strips) 
  • PICAXE for control Condenser microphone for detecting music 
  • Threshold beat detection with sensitivity control
  • 9V battery for power 
  • Comfortable on forearm (body made out of a sock)

Acoustic Landmine Detector

Acoustic Landmine Detector
Senior Design Project
Hisham Bedri - Tufts University (2011)
There are 110 million active landmines scattered across 70 countries worldwide. Many of these mines have plastic casings, making them very hard to detect using conventional metal-detectors. For my capstone project at Tufts University, I developed a low-cost prototype acoustic land-mine detector. Here is a summary music video. More project details are below:

Buried landmines can be hard to detect, especially if they have been buried for a long time. When vibrated. however, landmines interact dynamically with the soil around them. The detector works by transmitting two sound tones (two frequencies) and records the sound that bounces back. The detector analyzes the characteristic response of the landmine-dirt system and then determines whether a landmine is buried. 
Two frequencies are transmitted into the ground. The detection algorithm detects the non-linear combination of these two frequencies. These non-linear (non-harmonic) peaks in the spectrum of the response is caused by the landmine bouncing against its environment.
On top you can see that when there is no landmine, only the two transmitted frequencies are received. Below you can see the ideal reaction when there is a landmine buried.

Initial Setup:
Initial setup using an old receiver amplifier, speaker, and microphone. Objects tested were plastic pvc-endcaps (2-4 inches in diameter).

 Prototype and testing:
The portable prototype uses 2-9V batteries to run the amplifier and transducer and a laptop running matlab for signal processing. Testing was done at a nearby Airforce National Guard base using inert replica landmines.

The detector was able to discriminate areas with buried objects from those without buried objects with a probability of detection of 70%. The sample size used was too small to truly tell the functionality of the detector, however the initial results show a false alarm rate lower than most metal-based detectors and a probability of detection which is also comparable. Note that there is always a trade-off between probability of detection and false alarm rate.

This was a great project to learn about the concept of signal-detection. In the future I woudl like to validate the portable design by testing further, generating a full Receiver Operating Characterisc (ROC) curve, and implement an smart-phone app to perform the signal processing (so the whole rig will be more portable).

Tuesday, September 4, 2012

Hey funky people!

This is a blog to keep track of and showcase the work I'm doing. It's not exhaustive but will include some of the highlights. Let me know if you have any questions or if you want me to elaborate on anything. In most cases I'd be more than happy to share my technique/design.

We'll start with this SUPER SICK and INFINITELY EXTREME function generator by myself, Ryan Hofstetter, and Vinh Pham:


  • +/- 15V waveform generator
  • Pulse (square), Sawtooth, Sin-Wave
  • Amplitude control
  • Frequency control
  • Schmitt-Trigger Oscillator
  • See-through design (so you can see the gnomes working inside)
  • Ergonomic shoe-box space-age casing

Monday, November 21, 2011

There’s no app for that: Sudan sanctions are holding back innovation

Originally Published Thursday November 21, 2013

This one is more about policy than any new invention, however it's very much worth the read:

There’s no app for that: Sudan sanctions are holding back innovation

Hisham Bedri, MS Candidate, Technology and Policy Program, Massachusetts Institute of Technology

   In Sudan there is no app store. No Google play store. No credit cards. No Adobe Flash. You will be lucky to get your hands on Google Chrome web-browser, but even if you do, you will have to go to great efforts to circumvent blocks that prevent Google hangouts (video chat) from working. The content just “isn’t available in your country”. Due to US sanctions, the export of technologies from a US- firm or person to Sudan is prohibited, and the app-store is just the tip of the ice-berg. The implementation of sanctions has also had widespread detrimental effects on the Sudanese economy, however the true losers of the untargeted embargo is not the Sudanese government, but the Sudanese people who cannot join the global community. Furthermore, US firms and research institutions in the US lose out on trade and partnership opportunities. The Sudan Sanctions Regulations (SSR) administered by the Office of Foreign Assets Control (OFAC) are ineffective in changing the behavior of the Government of Sudan, place a heavy opportunity cost on the US companies and research institutions, and has lasting detrimental effects on the Sudanese people. The SSR must be amended to allow for the transfer of consumer technologies intended for the use of the Sudanese people and civic development.

   The SSR are split into two categories, general trade embargoes against Sudan, and targeted sanctions against the properties of individuals and entities contributing to the conflict in the Darfur region. While the latter is specifically targeted, the former is broad and has damaged the livelihoods of Sudanese people who are unrelated to the government. These general sanctions have had limited direct effect on changing the decisions of the government of Sudan, and have pushed humanitarian efforts backwards. In a 2009 report, OFAC’s evaluation of US sanctions on Sudan brought to light that sanctions have impeded the humanitarian process in Sudan.

   “As noted by USAID officials, sanctions or the threat of sanctions have increased GOS leadership’s feelings of being besieged. In response, the regime has sometimes reacted by increasing its harassment of U.S. humanitarian aid workers and U.N. peacekeepers, exacerbating the humanitarian and security situation for vulnerable populations.” Effectiveness of U.S. Economic Sanctions With Respect to Sudan (January 2009)

   These sanctions have been in place since 1998 after Executive Order 13067, which found the actions of the Government of Sudan (GOS) to be a threat to US foreign policy. The SSR were later sustained and modified in 2007 to ease sanctions on the Government of South Sudan (GOSS), and in 2009 to block the property of individuals connected with the crisis in Darfur. In 2010, following the heavy usage of twitter and Facebook in the protests following the Iranian elections, the US treasury made an announcement to lift sanctions on freely available web-technologies in Iran, Sudan, and Cuba. While this is a step in the right direction, the policy change falls short of granting access to many useful applications, such as apps which cost money or allow for online purchases. This shields the Sudanese market from a large many applications which operate on a “freemium” model, and prevents companies like Google from opening all of their services to Sudan.

   In addition to having a negative effect on the internet freedom of the people of Sudan, current policies prevent US technology firms from doing business in Sudan, which places an opportunity cost on US commerce and jobs. An example of this opportunity cost can be found in the trade between Sudan and the UK. Sudan is the UK’s 87th largest export market, and bilateral trade in 2008 alone was worth over $200 million. If our allies can develop commercial relationships with the people of Sudan, why can’t we? Furthermore, sanctions prevent the involvement of US companies in the development of Sudan’s oil industry. This costs American jobs while Sudan’s oil industry is being largely developed by China and other Asian nations.
   To say nothing of the detriment to American industry, the embargoes directly harm the Sudanese people, and may cause long-term damage to US-Sudan relations and foreign policy interests. In 2011, I conducted interviews in Sudan with members of industry, university professors, and TEDx organizers, and found that the embargoes had four major effects on industry and daily life in Sudan. First, Sudanese locomotive and aviation companies were crippled because many spare parts can only be sourced from US companies. Second, universities such as the Ahfad Unviersity for Women could not formalize long-standing relationships they had with US Universities. Third, mechanized agriculture suffers because spare parts and specialized technicians are blocked, leading to shutdowns and delays, such as in the delayed activation of the White Nile sugar factory because a US company purchased the software company which provided services to run the facility. Fourth, students in Science, Technology, Engineering, and Math (STEM) fields could not access certification programs, design software, or necessary equipment to complete their education. An egregious example of this is that Sudanese students hoping to work as computer technicians or in telecoms cannot take the CompTIA A+ or N+ certification exam for Microsoft products, an internationally recognized standard. Without the tools, Sudanese students are not able to compete globally in the innovation economy.
These sanctions, however, are not short term. American products and services have been blocked since 1998, meaning a whole generation of Sudanese has grown up with the implicit message that: “we don’t like you”. A message like this can have strong consequences for forming relationships with Sudan in the future. As one student at the University of Khartoum described the situation, “The right to access education and technology and compete with electronic grants and services is guaranteed by international human rights. The injured [by the sanctions] is the poor Sudanese citizen and not any minister or individual.”

   One teacher at the Ahfad University for Women stated that since they have no credit cards or access to electronic money transfers, she could not pay the fees for educational workshops and trainings, and that “We cannot keep up to date with new developments in the field of English language teaching, contemporary writers, or poets.”
   It’s time for the OFAC to take another progressive step and end the embargo of US consumer technology, business relationships, and educational partnerships in Sudan. The effectiveness of 15 years of sanctions is questionable, the benefit of the sanctions are contested and hard to quantify, their detriment to the Sudanese people is real, and the opportunity cost to US firms and institutions is serious. These sanctions fall out of line with US foreign policy interests. As former secretary of state Hillary Clinton remarked on internet freedom, “We stand for a single internet where all of humanity has equal access to knowledge and ideas. And we recognize that the world’s information infrastructure will become what we and others make of it. Now, this challenge may be new, but our responsibility to help ensure the free exchange of ideas goes back to the birth of our republic. The words of the First Amendment to our Constitution are carved in 50 tons of Tennessee marble on the front of this building. And every generation of Americans has worked to protect the values etched in that stone. “
   It’s time for us to stand up for American ideals and end the embargo of basic technology.