Speed Climbing Timing - Part 8 Hand and Foot Sensors
04/06/2009 06:49 Filed in: Speed timing | IR Sensors
Synopsis - In Part 8, I cover the finished hand and foot sensors to the speed climbing timing system. Way back in Part 1 and Part 4 of this series, we covered the IR sensors and touch pad design and construction....the “bones” of what you see here. This article includes a system block diagram and photos and explanations of the final design of the hand and foot sensors.
These sensors are “finished” in that they are more done than some of the other parts of the system, and finished enough that this is what we’ll install in the rock climbing gym for our first major tests.
First, here’s a quick block diagram of how the sensors are wired together. Understanding this will help the physical sensor enclosures that I’ll show you later make more sense.
We’re using RJ45 jacks and CAT5 wiring between the base station (LED display) and each of the sensors. So, any colored connection in the diagram above is CAT5.
Within each CAT5 run, the base station is using one pair for 5V and GND, one pair for Sensor 1 and one pair for Sensor 2 voltage signals. This leaves one of the 4 pairs unused (for now.)
In order to keep from having to run multiple lines up the wall, we decided it would be best to put the hand touch pads on one CAT5 up the wall and the foot sensors on the other CAT5. We could have tied them together by lane instead, but that would have meant two CAT5 cables going up the climbing wall and it would be somewhat harder to install.
The other major consideration was that we didn’t want to have any jumpers for left or right configuration on the sensors themselves. In other words, we wanted to build every sensor exactly the same so they could easily be swapped in and out of the system if one failed. So, each sensor is built identically as far as the electrical wiring and jacks. There is no left foot or right foot - only a foot. What’s left or right depends upon how they’re connected together according to the diagram above. You’ll see what I mean when you see the RJ45 jack configurations on the sensors.
Here are some shots of the finished hand sensor (well eventually the base board will be painted black also.)
(If you click these images you can get an enlargement of it.)
The white paint spot in the middle shows the sweet spot - if you hit that area, you’re pretty much guaranteed to stop the clock - much like a physical switch. If you whiff and hit somewhere else within the band between the two IR sensors, then you may or may not get a good stop (likely you’ll stop it, but best to try to hit the spot.)
The black hoods are 1/4” plywood which give the sensor mounts extra protection, but more importantly, we were worried that if the climber hit the metal sensor mount wrong, he or she could potentially cut their hand. It also cuts down ambient light from other angles, though the IR sensors have proven to be fairly discriminant in various lighting conditions.
You can see the metal mount in the center which is used to bolt the sensor to the climbing wall at the top of the speed route.
The picture above shows the back of the hand sensor. Items to note are the T-brace used for bolting the sensor to the climbing wall. Also, you can see a groove routed from the top about 2 inches. The sensor wires are passed through a 3/8” translucent tubing (standard water line you can buy in the plumbing section of a Home Depot). This both protects the wires from pinching against the wall and the routed groove allows the tube to rest within the plywood so the sensor can be mounted flush against a wall.
To the side of the hand sensor is an RJ45 array as seen above. Ignore the “CAT5B” - all jacks and wiring in the system will be CAT5A.
The way this works is simple. There is a CAT5 cable run from the base station display up to the hand sensor and it jacks into the “BASE” jack. Then a CAT5 patch cable is run from the OUT 2 to the second hand sensor on the top of the 2nd lane. If this were the 2nd lane’s hand sensor, the cable coming from Lane 1 is connected to the “2 IN” jack of lane 2’s hand sensor. This chain is depicted in the original block diagram.
Based on the way we have the internals wired, this will have the effect of discriminating lane one from lane 2 but allows us to build all sensors the same way.
Here are the internals of the RJ45 jack array. We put spade terminals on the end to easily mount and dismount the shroud in case it needed to be replaced.
The shot above shows a perspective with the RJ45 jack array, shroud design, and you can even see one of the IR sensors on the far metal mount sweeping across the bottom part of the sweet spot.
The foot sensors are electrically the same with one exception: there’s only one IR sensor in the foot pad. Several reasons why only one IR sensor was needed: the foot is only used for starts and false start detection. The foot can be easily constrained in a smaller space at the start than a wild hand at the top trying to stop the clock which needs more latitude.
Physically, the design of the footbed is similar in concept to the hand sensor but a different implementation because we wanted to constrain the foot enough that it would be hard to not be right where the IR can detect it (no slop, but still big enough to not catch the climbers foot when they take off on the start.)
Below is the basic design of the foot bed:
Same type of metal mounting brackets are used as we use in the hand sensor, but the base board accommodates a foot instead. Also, in order to keep the cabling away from the climber’s free foot on either side, we decided it would be best to route the cabling out the front or top of this sensor instead of the side of the sensor as it is on the hand. You can see the terminal strip mounted on the top of the sensor.
Also shown above is the black shroud for the toe-box and kick-plate. This shroud was designed to be a “kick-plate” for the toe, so the climber, when he or she steps into the foot bed, can put the toe of the shoe directly against the kick-plate and will then be in the right position for the IR sensor to pick it up. The IR sensor is positioned to easily span the ball of the foot from the side (and a lot more). So, when the climber is standing anywhere in the box, there’s almost no way the IR sensor will not detect the foot. The climber’s toe would have to be all the way at the back of the footbed practically for the IR sensor to not see it.
The foot bed is also designed to not be long enough heel to toe for an average sized kids foot to fit. Most climbers will be on the ball of their foot as they get set to for the start. For a size 8 or 9, the climber’s heel will overlap the end of the board. This again, encourages them to have their foot in the spot where the sensor will pick it up.
Finally, if the climber will place the ball of their foot so that it lines up with the white arrows on the shroud, it will be in the sweet spot of the footbed.
All these design elements will help ensure a reliable detection of the foot for false start detection.
Here’s how the foot sensor looks when the shroud is installed. You can see the black kick-plate in the toe which both helps position the climbers foot in the right spot, but also protects the RJ45 array in the toe-box from damage. Since the shroud rests over the metal mounts, it has additional support in case a climber stepped on the top of the shroud so the footbed is very rugged as well. The whole footbed, while not heavy is wide and stable and won’t easily get tossed.
The RJ45 array is installed in the toe of the footbed so that cables can be easily and safely routed out the front of the footbed so they won’t get tangled with the climber’s free foot during the start of the race:
It has an identical wiring plan and RJ45 array as the hand sensors. The BASE jack goes to the base station display. The “2 OUT” goes to the 2nd lane’s footbed, and the 2nd lane’s footbed accepts the cable in its “2 IN” jack. Very simple wiring scheme.
This view shows the best angle to see the kick-plate (black) on the toe that protects the RJ45 jack array in the front as well as helps align and guide the foot to the right spot. If the climber has their shoe toe against the front kick-plate inside the box, their foot will be easily detectable by the IR sensor seen on the left under the metal mount.
Speed Climbing Timing Part 1 - Sensors
Speed Climbing Timing Part 2 - Controller
Speed Climbing Timing Part 3 - Integration
Speed Climbing Timing Part 4 - Touch Pad Construction
Speed Climbing Timing Part 5 - Schematics
Speed Climbing Timing Part 6 - Perf Board
Speed Climbing Timing Part 7 - Display
Speed Climbing Timing Part 8 - Hand and Foot Sensors
Speed Climbing Timing Part 9 - Demonstration
Speed Climbing Timing Beta Test Boulder Rock Club
Speed Climbing Timing - Sensor Improvements
Speed Climbing Timing SHIPPED!
Speed Climbing Timing Schematics (shipped v1)
Speed Climbing Timing Installation
Speed Climbing Timing - Laser-based Hand Sensor Design
Speed Climbing Timing Lessons Learned
These sensors are “finished” in that they are more done than some of the other parts of the system, and finished enough that this is what we’ll install in the rock climbing gym for our first major tests.
First, here’s a quick block diagram of how the sensors are wired together. Understanding this will help the physical sensor enclosures that I’ll show you later make more sense.
We’re using RJ45 jacks and CAT5 wiring between the base station (LED display) and each of the sensors. So, any colored connection in the diagram above is CAT5.
Within each CAT5 run, the base station is using one pair for 5V and GND, one pair for Sensor 1 and one pair for Sensor 2 voltage signals. This leaves one of the 4 pairs unused (for now.)
In order to keep from having to run multiple lines up the wall, we decided it would be best to put the hand touch pads on one CAT5 up the wall and the foot sensors on the other CAT5. We could have tied them together by lane instead, but that would have meant two CAT5 cables going up the climbing wall and it would be somewhat harder to install.
The other major consideration was that we didn’t want to have any jumpers for left or right configuration on the sensors themselves. In other words, we wanted to build every sensor exactly the same so they could easily be swapped in and out of the system if one failed. So, each sensor is built identically as far as the electrical wiring and jacks. There is no left foot or right foot - only a foot. What’s left or right depends upon how they’re connected together according to the diagram above. You’ll see what I mean when you see the RJ45 jack configurations on the sensors.
Here are some shots of the finished hand sensor (well eventually the base board will be painted black also.)
(If you click these images you can get an enlargement of it.)
The white paint spot in the middle shows the sweet spot - if you hit that area, you’re pretty much guaranteed to stop the clock - much like a physical switch. If you whiff and hit somewhere else within the band between the two IR sensors, then you may or may not get a good stop (likely you’ll stop it, but best to try to hit the spot.)
The black hoods are 1/4” plywood which give the sensor mounts extra protection, but more importantly, we were worried that if the climber hit the metal sensor mount wrong, he or she could potentially cut their hand. It also cuts down ambient light from other angles, though the IR sensors have proven to be fairly discriminant in various lighting conditions.
You can see the metal mount in the center which is used to bolt the sensor to the climbing wall at the top of the speed route.
The picture above shows the back of the hand sensor. Items to note are the T-brace used for bolting the sensor to the climbing wall. Also, you can see a groove routed from the top about 2 inches. The sensor wires are passed through a 3/8” translucent tubing (standard water line you can buy in the plumbing section of a Home Depot). This both protects the wires from pinching against the wall and the routed groove allows the tube to rest within the plywood so the sensor can be mounted flush against a wall.
To the side of the hand sensor is an RJ45 array as seen above. Ignore the “CAT5B” - all jacks and wiring in the system will be CAT5A.
The way this works is simple. There is a CAT5 cable run from the base station display up to the hand sensor and it jacks into the “BASE” jack. Then a CAT5 patch cable is run from the OUT 2 to the second hand sensor on the top of the 2nd lane. If this were the 2nd lane’s hand sensor, the cable coming from Lane 1 is connected to the “2 IN” jack of lane 2’s hand sensor. This chain is depicted in the original block diagram.
Based on the way we have the internals wired, this will have the effect of discriminating lane one from lane 2 but allows us to build all sensors the same way.
Here are the internals of the RJ45 jack array. We put spade terminals on the end to easily mount and dismount the shroud in case it needed to be replaced.
The shot above shows a perspective with the RJ45 jack array, shroud design, and you can even see one of the IR sensors on the far metal mount sweeping across the bottom part of the sweet spot.
The foot sensors are electrically the same with one exception: there’s only one IR sensor in the foot pad. Several reasons why only one IR sensor was needed: the foot is only used for starts and false start detection. The foot can be easily constrained in a smaller space at the start than a wild hand at the top trying to stop the clock which needs more latitude.
Physically, the design of the footbed is similar in concept to the hand sensor but a different implementation because we wanted to constrain the foot enough that it would be hard to not be right where the IR can detect it (no slop, but still big enough to not catch the climbers foot when they take off on the start.)
Below is the basic design of the foot bed:
Same type of metal mounting brackets are used as we use in the hand sensor, but the base board accommodates a foot instead. Also, in order to keep the cabling away from the climber’s free foot on either side, we decided it would be best to route the cabling out the front or top of this sensor instead of the side of the sensor as it is on the hand. You can see the terminal strip mounted on the top of the sensor.
Also shown above is the black shroud for the toe-box and kick-plate. This shroud was designed to be a “kick-plate” for the toe, so the climber, when he or she steps into the foot bed, can put the toe of the shoe directly against the kick-plate and will then be in the right position for the IR sensor to pick it up. The IR sensor is positioned to easily span the ball of the foot from the side (and a lot more). So, when the climber is standing anywhere in the box, there’s almost no way the IR sensor will not detect the foot. The climber’s toe would have to be all the way at the back of the footbed practically for the IR sensor to not see it.
The foot bed is also designed to not be long enough heel to toe for an average sized kids foot to fit. Most climbers will be on the ball of their foot as they get set to for the start. For a size 8 or 9, the climber’s heel will overlap the end of the board. This again, encourages them to have their foot in the spot where the sensor will pick it up.
Finally, if the climber will place the ball of their foot so that it lines up with the white arrows on the shroud, it will be in the sweet spot of the footbed.
All these design elements will help ensure a reliable detection of the foot for false start detection.
Here’s how the foot sensor looks when the shroud is installed. You can see the black kick-plate in the toe which both helps position the climbers foot in the right spot, but also protects the RJ45 array in the toe-box from damage. Since the shroud rests over the metal mounts, it has additional support in case a climber stepped on the top of the shroud so the footbed is very rugged as well. The whole footbed, while not heavy is wide and stable and won’t easily get tossed.
The RJ45 array is installed in the toe of the footbed so that cables can be easily and safely routed out the front of the footbed so they won’t get tangled with the climber’s free foot during the start of the race:
It has an identical wiring plan and RJ45 array as the hand sensors. The BASE jack goes to the base station display. The “2 OUT” goes to the 2nd lane’s footbed, and the 2nd lane’s footbed accepts the cable in its “2 IN” jack. Very simple wiring scheme.
This view shows the best angle to see the kick-plate (black) on the toe that protects the RJ45 jack array in the front as well as helps align and guide the foot to the right spot. If the climber has their shoe toe against the front kick-plate inside the box, their foot will be easily detectable by the IR sensor seen on the left under the metal mount.
Speed Climbing Timing Part 1 - Sensors
Speed Climbing Timing Part 2 - Controller
Speed Climbing Timing Part 3 - Integration
Speed Climbing Timing Part 4 - Touch Pad Construction
Speed Climbing Timing Part 5 - Schematics
Speed Climbing Timing Part 6 - Perf Board
Speed Climbing Timing Part 7 - Display
Speed Climbing Timing Part 8 - Hand and Foot Sensors
Speed Climbing Timing Part 9 - Demonstration
Speed Climbing Timing Beta Test Boulder Rock Club
Speed Climbing Timing - Sensor Improvements
Speed Climbing Timing SHIPPED!
Speed Climbing Timing Schematics (shipped v1)
Speed Climbing Timing Installation
Speed Climbing Timing - Laser-based Hand Sensor Design
Speed Climbing Timing Lessons Learned
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