I’m really curious about projects for the blind because my dog is now a senior with low vision. He can walk into trees in daylight, often has problems locating me in the house, and has to be very careful on steps. So, this project that I spotted on Hackaday is definitely of interest, and I’m hopeful that some day it may even be used for animal companions. It’s called Pathfinder and it’s a Hackaday 2015 Semifinalist by Neil Moova. This wrist friendly wearable helps to locate the distance of objects and responds with haptic feedback to a fingertip. It uses an ultrasonic sensor HC-SRO4, which you often find on small bots, with what looks like a Mini Arduino Pro. You can see one of the earlier models on one of Neil’s custom PCB’s above, which later got switched to an even nicer PCB with a Teensy 3.1.
One of the interesting parts of the project was Neil’s testing with people from Santa Clara Valley Center for the Blind. His visits were often dominated by discussions of needs and abilities, so he developed some specific tests so he could continue his work.
On my own, I was able to perform more scientific trials, and so I designed a repeatable gauntlet of tests that I or other sighted users could perform while blindfolded to demonstrate typical use of the device. The tests are as follows:
1. Picking up a glass of water on a table (90cm wide), placed randomly between 20 and 80 centimeters away from the user. Spills constitute failure.
2. Find a person in an open area, with no initial orientation. Hitting walls or accidentally running into the person constitutes failure.
3. Navigate around randomly placed obstacles in a room. Contact constitutes failure.
After some time, Neil found himself able to navigate with the glove and he managed to pass all three tests. That’s pretty amazing, especially considering the water hazard.
Neil’s final board looks great, but he does mention the he forgot a header in his design. It’s a minor issue considering his finished bill of materials is $19.77 and his files are ready to go. That’s going to make some people very happy, but what about blind dogs? Seriously, I’m wondering if the ultrasonic sensor could be worn on a collar, while the board and vibration motor could be mounted on a harness around the dog’s body. I’m sure training the dog to use the system would be tricky and I’m not sure if multiple vibration sensors would be needed. However, it’s definitely a fun project to consider. If you want to learn more about using an ultrasonic sensor, check out our Trinket Ultrasonic Rangefinder Learning Guide. It’s a great example of how handy these sensors are, and after reading it you’ll at least understand how those crazy back-up beeping alarms work on cars.
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