March 20, 2019

Build Your Own Sonar Navigation System

DIY-Tacit-Haptic-GloveThere has been a lot of buzz about the Tacit Project, A.K.A. “Sonar for the Blind,”  recently.  According to the inventor, Steve Hoefer, Tacit is the shorter and less descriptive name he has given his design for the “Hand Mounted Haptic Feedback Sonar Obstacle Avoidance Asstance Device”.  In brief, what Tacit does is measure the distance to objects and then translate that measurement into pressure on the user’s wrist.  The pressure increases as the distance decreases. Hoefer says that the device is very fast and accurate from just about one inch to ten feet.

Hoefer designed Tacit to help visually impaired persons navigate complex environments.  Some of the original designs were headband-based, but were scrapped for three very good reasons:

  1.  The most dangerous obstacles are not at head level. Furniture and most of the other things that can be tripped over and stubbed on are waist level or lower.
  2.  Vibrating motors stuck on your skull will drive you insane quickly.
  3. You would also look like a crazy person.

While we are not ready to jump on the “throw away your cane and leave your guide dog at home” bandwagon, we were hooked by the do-it-yourself aspect of this project. Tacit consists of two small Parallax Ping Ultrasonic sensors connected through a controller to two padded servo motors. The electronics are mounted on a custom neoprene wrist strap and powered by a 9-volt battery. The parts list, schematics, and source code are freely available and the whole project can be built for about $65 under the Creative Commons license. This may just be enough to get us to dust off our old soldering iron and talking multi-meter (yes, we really have one. Don’t you?) and get started. We probably need to clear away the Lego Mindstorm NXT robot debris from the workbench first.

What kinds of home brew projects have you been building in your basement?

RFID Technology Makes Navigation More Accessible

Man with guide dog, using RFID technologyOne of our special interests is the use of technologies such as RFID (Radio Frequency Identification) and NFC (near field communication) in the area of disability. The wide availability of accessible smart phones and the relative low cost of developing applications for them opens the door to many possibilities. A story written by Alena Roberts and recently published in the Matilda Ziegler Magazine describes the Talking Tags RFID Wayfinding project of Guide Dogs for the Blind of the UK that uses RFID technology to aid both indoor and outdoor navigation. Here is the original story reprinted here with permission:

 Using RFID Technology to Make Indoor and Outdoor Navigation Accessible

by Alena Roberts

Navigating to new locations has become progressively more accessible for the blind in recent years. In fact, last year I did a whole series on low cost accessible GPS options. Unfortunately, as awesome as GPS is, it’s limited primarily to the outdoors. So what this means is that we can now get to our destination’s front door, but we may not know how to get to where we need to be once we’re inside. Thanks though to a new partnership between Guide Dogs in the UK and the University of Redding, this problem may also soon be solved. The Talking Tags Way Finding Project is using RFID technology to overcome the limitations of GPS.

So how does the system work? The system comprises of three components: RFID tags, a handheld receiver, and a database of prerecorded messages for each tag. The tags themselves are usually as small as a credit card, so they can be put essentially everywhere. RFID also doesn’t require the user to find the tag, but simply to be near enough for the receiver to find it. Once the receiver finds the tag, the message is spoken. It’s that simple.

RFID technology has been used for years in industrial shipping applications and warehouse inventory to track products because it’s a simple system that doesn’t take up much space or carry a high cost. By using the technology for indoor navigation, this would be great for all kinds of situations including malls or other buildings that have multiple stores or offices. It could also be used at bus stops and even intersections to let the user know where they are. All of this can be accomplished very easily without the addition of any large equipment.

Here are some of the features of the Talking Way Finding system.
- The Talking Tag can either be temporary or permanently placed
- The tags can be used indoors or outdoors
- Different languages can be used
- Low cost of installation, running, and maintenance
- The handheld receiver is light weight and will last all day
- A Smart Phone app could be created to avoid the need of a special receiver

The system is still in prototype stage, but it’s Guide Dogs’ hope that the system will be available for use in 2012 or 2013. Visit the Talking Tags project site to learn more about the project.