Some (more) thoughts on smart canes

Why more?

In early 2021, I wrote a blog post about smart canes, why they usually are hipe, and why canes have design elements that make them so versatile. This blog post got a couple orders of magnitude more traffic than I expected, and based on the feedback I have received, it was educational for many people. It has been posted on many peoples blogs, and even Hacker News. I want to make sure the positive reception of my article is used to guide the industry in an appropriate direction, and generate new useful technologies, instead of being synical and bashing anyone who may have the thought to attach something to a cane.

I will do this by explaining some of the drawbacks to having objects on a cane, and travel implements we could design that would achieve useful goals for blind people, while being more robust.

What does a cane do anyway?

Humans make it move back and forth for a long time

A good cane is a lightweight stick that is long enough to have its end swept from one side of the user's body to the other and provide enough warning to the user of an upcoming danger that they can realistically react and avoid that object. The sweep occurs in the time it takes for one foot to be moved from its backmost position to its forward most position while walking. This means that the faster a user is walking, the faster the user's cane must be moved from one side of the body to the other for detection purposes. The cane should be light, but more importantly, the cane should be easy to move across the body fast, hundreds of times in a row without significantly fatiguing the user. There is one variable in particular that causes movement of a cane to become more difficult. Tie a rock to the end of a stick. If you have them available, get several sticks, from about 1 meter, to about 2.5 meters. Getting rocks of varying sizes will also help with this exercise. Swing the rock stick around, keeping the rock on the ground. Use different lengths of stick, or slide your hand closer to the rock and swing it. Notice how it is harder to swing the stick when the rock becomes heavier, and/or the rock is further from your hand. This is called torque, and torque increases proportionally as you add weight further from your hand or increase the length. Immagine this rock+stick is a cane instead. Adding a heavy tip to a cane makes moving that object much more difficult, because the torque you must apply to that cane tip increases as you move it further from your hand, or increase its weight. Also, when a blind person is using a cane with proper technique, the wrist acts as the pivot, and the rest of the arm should remain relatively still. Thus, my elbows and shoulders do not help me apply torque to objects on the cane very much. Thus, heavy tips make using a cane harder, and attaching a camera, batteries, random tech, etc. to a cane increases the torque applied to my wrist by a huge amount, especially if that battery is not directly under my hand. I recently did a demo where I attached a 10,000 MaH battery to the bottom of a handle of an ambutech cane, about where the first joint is, to simulate a camera+battery housing. The cane became practically impossible to use for long periods of time effectively if walking with realistic speeds for a busy person. This tires my hands out way faster, and is especially hard for the elderly, who are more likely to have arthritis, and who are a huge beneficiary of smart sensor technology because they don't want to have to relearn everything.

It gets beaten up

In my previous article I talk about canes being run over by bikes, tripped on by people, etc. This really is a huge deal. Sometimes, dogs think canes are a really cool huge stick, and want to play. It's pretty common for a dog to just start chewing on my cane if I leave it under a table, or even at a park if I'm not swinging it around. Other times, canes literally get run over by a bike, or tripped on by a pedestrian. In these cases, sometimes I will intentionally drop the cane if I am concerned the accident is serious enough to injure the person, because the cane can hit the ground and it won't care. I also know blind people who have had canes run over by cars. Ambutech canes can also unfold often, but users of straight canes or canes with a non-conical folding mechanism don't get this benefit. Thus, dropping a cane to prevent it from hurting someone is an important safety trick. I have another experiment here to perform. Take your phone out of your pocket, and throw it at the ground as hard as you can. I dare you. What, you don't want to ruin your phone? Good. I don't want to ruin my smart cane either, so now a biker is on the ground injured, or the force of a bike hitting my cane knocked it out of my hand. Goodbye nice expensive lidar system. This isn't the only time I throw my cane to the ground. At work, I'm often filling up a cup of coffee. I'll throw my cane on the ground, kick it under the molding on the edge of the counter so it's not a tripping hazard, then sanitize my hands. I'm not gentle with it, because it's a tool that is designed to be that rugged. If it can't take the abuse of a busy person who wants to use it as that kind of tool, it isn't worthy of being in my hand. I don't want to touch the ground to put it there because that increases the chance that I'll soil my hands even more, so I just drop it and give it a kick to get it under the counter, it's not going to hurt my cane. Likewise, leaning it against a wall can be a problem because it could fall over and hit someone or knock coffee off of a counter, etc. AN object cannot lose potential energy if it has no potential energy to lose, so I just put it on the ground. After washing my hands and getting coffee, I'll pick up the cane, and assault it with a very harsh disinfectant because I touch it constantly. I couldn't do this with a smart cane. I've taken my cane to lakes before, and used them to board a boat, or measure the depth of some water, etc. Canes make a decent rough measuring stick because I know approximately how far it is to reach each fold on my canes. Not all are suitable for this, but carbon fiber and aluminum don't rust, so this works for my case. There's a non-trivial chance that if I'm on a boat, my cane will get wet. I've also got no choice but to use the cane in a downpour sometimes. This also seems to be a problem with smart canes 1. If I cannot get it wet, or it can't even handle a rainstorm, it isn't useful. Sometimes life just throws a downpour at you. Suck it up and walk home or hide in a hole to protect your smart cane.

The cane isn't always going to move in the same way

I don't only move my cane from left to right. There are times when I reach the other side of a street, and use my cane kind of like a probe to figure out if there's an inset sidewalk, or if I ecolocated something tall and skinny, I might ding it with the cane to see if it rings out like a sign post or know what shape of pole it has. I might ding it pretty hard sometimes too to see if the thing is hollow or hard. or, (and teachers hate this one but I really don't care because I'm an adult who knows how to do things safely) I'll use the end to see if there's a sign at like 8 feet and what shape it is. Don't worry, I do that in a controlled way to make sure I don't give someone a helmet check. If I'm crossing a street I hold it in front of me, in such a way that my arm and the cane almost make a 7 shape where the long part of the 7 is across the front of my body. These aren't the only ways I use a cane in ways that don't just go back and forth, but this should explain my next point. Any cameras or smart tech on the cane do not guarantee a stable reference point. If My cane is being held in the 7 position, the camera isn't pointed forward. If I am crossing a street and switch from constant contact technique to two-tab technique, or some random combination, the camera won't even be guaranteed to be a fixed and known distance from the ground. Also, when navigating crowds I keep my cane at a radically more steep angle with the ground so that it isn't a tripping hazard. This would cause the cameras to be pointed in yet another strange direction. Even with an accelerometer or gyro, this adds extra processing which is going to kill its battery faster and add weight.

An obvious solution

I seriously don't get the point of putting this tech into a cane. A chest mounted camera system can be worn in a much more comfortable way, isn't being put in a lake or thrown at the ground, and (well hopefully) isn't being run over by people, bikes, or cars, or thrown at the ground. Okay, if you're in a marshall arts class maybe don't wear your smart chest mount. A chest mounted camera system can also be covered and protected by an oversized rain jacket to protect it, or simply turned off and have its battery isolated from the circuits. Finally, if a chest mount doesn't work, a head mounted camera might be a solution, but only for some people. Some visual disorders cause jerky head movements, especially if the optic nerve is damaged in such a way as to cause the brain to receive fantom signals that the brain interprets as visual signals. They aren't useful visual signals, but it can cause certain blind people's heads to jerk around randomly because the brain is trying to get visual information from the eyes based on the bogus info the optic nerve is sending. This is why I think a chest mount is better than a head mounted camera, plus the torso is more likely to be pointed in the direction of travel.


1: "Is WeWALK suitable for use In rainy weather? Heavy or torrential rain will stop your WeWALK from working properly and should be avoided. Prolonged or repeated exposure to water or heavy rain must be prevented as it may cause permanent water damage to your WeWALK. If you are out with your WeWALK and are caught in heavy rain, you should immediately switch the cane off and cover it to protect it from heavy rain. You can continue to use the WeWALK as a traditional white cane to navigate during the rain, but the obstacle detection function will not be available while the device is covered. You can remove the cover, switch on your WeWALK, and continue on your journey as normal once the rain stops. If your cane does get wet, allow it to dry naturally in the open air at room temperature.
Retrieved from on ## Why more?