Total new guy here, no experience programming or using micro controllers. I am, however, a tinkerer by nature and industrial engineer by trade! Love learning new stuff. I have spent several hours on Google looking for what's possible in solving my problem but didn't find a concrete resolution... I suspect as a result of my lack of hands on experience in this space.
I'm asking this community for a sniff test. I can speak logically/scientifically but relevant hardware is a no go so any help you have to offer need not include specific specs, parts, models, or code. Thanks in advance
Consider first these constants in the environment:
(A) Climbing harness
(B) Climbing wall
(C) Auto-belay* rope line
*a specially purposed cord reel hung above climbing walls allowing controlled descent speed of climbers
Challenge: Climbers ascend (B) without first attaching (C) to (A).
Proposed Solution:
Affix passive RF tag to (C) at Climber's end of the rope -- AKA "C-tag"
Affix passive RF tag to (B) at fixed height, say 15' from floor -- AKA "B-tag"
Build/Buy/Program a mobile, battery powered, programmable device with RF detector and audible buzzer to be hung from (A)
Logic:
i] IF (A) senses only (B) THEN audible alarm sounds
ii] IF (A) senses (B) AND (C) THEN null
iii] IF (A) senses only (C) THEN null
Is my idea feasible?
If not, which constraint is prohibitive? Size, power, technology, range, cost?
Are there more efficient ways to accomplish this safety task?
I'm not sure I have your whole concept in mind, but bear in mind that RFID tags only operate over a few inches. So if your climber is at the 15 foot point, the rfid tag at the top of the wall (I assume that's w here it is, from your description) will be out of detection range.
I think an RF-based solution would be very difficult to implement; you can't just stop signal from going past a few meters and in all directions. Easier would be a harness with an altimeter (usually sensitive to +-1m) that checks for the belaying rope when a climber passes 2m.
I feel you're trying to use technology to solve a management issue. It would appear you don't have sufficient staffing to provide proper supervision so that they don't have a chance to start climbing without being clipped in. It also indicates a lack of safety culture that ensures climbers are competent and self checking properly before being allowed to solo. Those are issues that need to be resolved before looking at technology.
There are already products like the belay gate that block access to the lower holds until the rope is removed from the gate.
With that in mind, and if you really had to use electronics, then you could use an ultrasonic sensor mounted on the wall just above head height to detect when a climber goes past. To detect if the rope is in use, attach a switch to the ring at the bottom of the wall that the belay attaches to when not in use, so that tension in the rope activates the switch. Then have a simple code loop that sets off an alarm if the ultrasonic sensor is triggered while the rope is not in use.
Realistically though it's a compromise that should be dealt with by proper staffing. And will be an inferior solution to a belay gate.
I was trained to climb telegraph poles safely, the training included checking that my harness was undamaged, safe and correctly fastened. I also used to go potholing, again, the safety of ropes, carabineers and other equipment I was using was my responsibility.
That was over 40 years ago.
More recently I went on a zip wire for charity. As soon as I was given my harness I started checking it. The guy who gave it to me asked what I was doing, so I told him. He said they had been checked so I didn't need to. He's an idiot, the person who is going to get injured or killed is me, not him.
Teach people how to check their equipment properly and make it an absolute rule that any infringement of the rules will result in a ban.
What an excellent community of thinkers and doers here. Thanks for the insights and ideas. Apologies for the delayed response...it appears I didn't set up notifications correctly so lucky I just came back to check manually.
Point well taken on RFID limitations. I feel now that's an over engineered solution now given other responses
I see your points on personal responsibility and staff management. While I'm just a friendly neighborhood gym member with a hobby for problem solving I hope I'll be inspired to add one more layer of passive, low (ish) tech safety to the system.
**Back Story: I am only a couple months into climbing and despite intro training, belay gates in place, AND no previous failures to clip in, I had a moment where I started climbing without clipping. The staff immediately saved me as they saw me from the very start, waiting to see if I was intending to only climb the first 10' (normal activity not requiring belay) or in fact making the aforementioned mistake. There's a term called "poke yoke" in the manufacturing world--"Fool proof". I was saved by the staff but I strive for a world where such intervention is redundant at worst, unnecessary at best. I became the guy I thought I'd never be. Surely I would notice if I wasn't clipped in! Welp.
I like a combo of ideas mentioned above. Tension-switch attached to belay gate paired with a harness altimeter. At X meters high, check for switch status. Ultrasonic sensor has some drawbacks regarding positioning on the wall. Might be over-engineering the solution?
Follow up questions, keeping it high level:
•Do any components mentioned here fall within "advanced" knowledge required? I don't mean earnest research and trial error work. More like tricks-of-the-trade-required-for-entry stuff.
•What method is recommended for communicating wirelessly with priority on minimizing hardware size and power consumption?
I think I can take it from here with Dr. Google. Thanks again everybody. Arduino forum did not disappoint!
I first went rock climbing (seriously) in circa 1977 whilst in College learing about Electronics and Microcontrollers. I have over the years taught rock climbing indoors and out and am a qualified instructor too.
Myself, also as an experienced electronics designer, I would not even consider any form of hobby DIY automated or fancy method to warn if anyone was not clipped in. Never.
If such a system went wrong, and someone was injured or killed, the liability issues would be enourmous.
It may be prudent to check the fumes given off by the "device."
The climbing equipment I buy is expensive. It does not cost all that much to make the climbing equipment. So, why is it so expensive?
Liability insurance.
If I fall, I want to had been using the equipment that is going to payout the most to my wife.
Let's say, I stored my climbing rope in the garage on a shelf. In the garage is a gas can for the lawn mower. When it gets warm in the garage the gas can vents. Liability insurance on the climbing rope is now null and void.
So will your project give off fumes or heat that will put it in close proximity to your climbing harness, your rope, or any other synthetic climbing equipment?
Seriously, I take a picture of where and how my climbing equipment is stored, once a season, for liability reasons.
Seriously consider the liability you'll come under messing with climbing equipment.
Still, your idea is sound. I trust my climbing partner to look over my rig carefully before being allowed to climb but strange things can happen. My climbing partner is a single stage check, it would be nice to have another independent check.
Most of the things mentioned above (solutions, I mean) are on breakout boards that you just plug in to the Arduino following basic schematics, then they have extremely simple code with many examples. For that, definitely not tricky. If you want to reduce size, you can mount all of the surface mount components onto a PCB, and that gets complicated.
As for wireless communication, you have several options. I've used Bluetooth and NRF24L01s which, I believe, are/can be low power consumers. However, I would just mount a buzzer onto the system so you have less to rely on. As has been said above, yes, you should be checking properly before climbing. But I don't see the issue with including a backup that is only a last line of defense and not relied upon... Anyways, as it would be a last line for preventing unsafe climbing, I would avoid any weak points. Relying on a wireless connection can cause issues - my Bluetooth headphones disconnected themselves while I was typing this - so a solid connection may be better.
Thinking an ENCODER linked to one of the pulleys would give better response times and more durability.
Press button to start climbing.
If encoder is not counting within a set period start a red flashing light.
Press button again to reset.
If encoder is counting person is climbing.
OR
Safety key must be engaged from the climb line (Lanyard type) to a small portable pack carried by the climber.
Like the kill switch used on seadoos etc.
Climber must engage kill switch to be able to climb.
Similar to above with a beacon to warn of an issue and no beacon or steady green / no siren to climb
Both simple to make and more reliable than RF devices as even RFID can carry to over a meter.
Aint the drop that kills you its the stop at the bottom.
What happens if your system fails? I would suggest you do a DFMEA (Design Failure Mode Effect Analysis) and map that to your liability coverage. Then carefully read all the disclaimers with each piece you purchase.
