TinyCircuits Forum

General Category => General Discussion => Topic started by: karl_lew on January 10, 2020, 04:00:28 PM

Title: The Hap-eRanger: a haptic TOF ranging support cane
Post by: karl_lew on January 10, 2020, 04:00:28 PM
I'm gradually losing my sight, so I decided to work on a project that might help in the years to come.

By way of introduction, I'll start this post with a description of what blind people do to get around. Blind people generally use "support canes for the visually impaired." These are those long, collapsible red-and-white canes one sees on the streets. These canes are remarkable devices on their own and afford tremendous mobility to people who might otherwise suffer alone in their house. The support canes represent freedom.

Yet there is one significant drawback to the support cane. As with most drawbacks, it is related to what the support cane does best. Support canes reach out and tap objects. They are touch wands that tap their way through our world, allowing us to perceive what is out there. And that tapping is horrible when one taps a person. That tapping violates their personal space. This means that blind people cannot freely use their support canes in crowded spaces with people whose backs are turned to the support cane. There will be awkwardness and embarrassment as people are tapped from behind.

I've long been a fan of TinyCircuits. And when I learned about the Time-of-Flight (TOF) ranging sensor, I was quite excited. HERE is a sensor that can be used to build a touch-less support cane. Indeed, with all the Wirelings, all of a sudden we've got ALL the parts needed to make such a support cane.

I call it the Hap-eRanger https://github.com/oyamist/om-ranger (https://github.com/oyamist/om-ranger). It is a haptic electronic rangefinder that uses the TOF Class 1 laser to emulate a support cane. The Hap-eRanger uses a LOT of TinyCircuit parts. It uses the TinyZero MCU with that critically needed 3-axis accelerometer. It uses the LRA Driver for haptic feedback. It uses an RBG LED. It uses a 500mAh LiPo battery. It has a 3D-printed case.

The other thing that may be of interest is that the Hap-eRanger uses Operating system Milli (OMilli), which basically turns your Arduino MCU into a multi-threaded operating system to support all your TinyCircuit devices. :D

Anyhow, RSVP if interested and we'll take it from there! :D
Title: Re: The Hap-eRanger: a haptic TOF ranging support cane
Post by: lennevia on January 13, 2020, 01:14:21 PM
Title: Re: The Hap-eRanger: a haptic TOF ranging support cane
Post by: karl_lew on January 14, 2020, 12:29:08 PM
 :D  RSVP's indeed.

Well. OK. I'm guessing you want to know what's happening, so here goes...

I'm wrapping up the design for the case (the STL's are in the github repository) and have had to work out tricky details such as how to mount an LRA Wireling board securely without damaging wires. The prototype uses small zip-ties to fasten the LRA and cable separately, protecting the thin LRA wires while permitting some freedom of movement for the LRA buzzer to vibrate. I broke 5 LRA Wirelings coming up with this design, which fortunately is now effective.


Another interesting challenge has been figuring out how to mount the TOF Wireling. The TOF Wireling uses a Class 1 infrared laser that has a range of about 2m under ideal conditions. Protective glass impairs range sensitivity, so I had to opt for a recessed design.  Fasteners are also a challenge in a small form factor. The TOF case is fastened to the main case with an internal zip-tie.



Also, if you know any blind people who might be interested in evaluating this, let me know. I do have testers other than myself, but the more the merrier.