IR Sensors
Speed Climbing Timing - Sensor Improvements
05/22/2009 08:39
Synopsis: We’re into the 20% of the project that takes 80% of the time. In this case, after the regional championship and another day’s session at the Boulder Rock Club, I decided I needed to make further improvements to the detection at the hand-sensors. In this article I have two videos - one showing a typical detection failure of the first generation hand-sensor and the second video showing some standalone tests of the 2nd generation sensor after an ATMega8 micro was installed in the end-cap of the hand-sensor in order to do the voltage comparison. The second video also shows the 2nd generation sensor which includes a bright LED on the end cap to help show the climber that the detection occurred.
The first video below shows an analysis in slow motion of a typical 1st generation sensor detection failure.
Videos below the break..... Read More...
The first video below shows an analysis in slow motion of a typical 1st generation sensor detection failure.
Videos below the break..... Read More...
Speed Climbing Timing - Part 8 Hand and Foot Sensors
04/06/2009 06:49
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.
Diagrams and images below the break...read on... Read More...
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.
Diagrams and images below the break...read on... Read More...
Speed Climbing Timing - Part 6 Perf Board
03/10/2009 14:34
Synopsis: Over the past weekend, I spent the time to take the sensor analog and digital interrupt logic off the breadboard and onto a more semi-permanent perf board. In the process, instead of a single sensor circuit which I’ve been using on the breadboard, this perf board incorporates all the circuitry for 4 sensors ( hand and foot X 2 lanes.) This perf board implements the schematics in Part 5 of this series with one exception...I added 4 LED indicators through another driver to show on-board when a sensor “fired” due to a touch.
Also, in this article are a couple of movies that show a single-sensor alpha test on a climbing wall.
Here’s a picture of the perf-board that contains the sensor detection and microcontroller interrupt logic for a two-lane speed climbing system. The microcontroller is on a separate board. The schematics for this board can be found in Part 5 of this series. The 4 orange potentiometers on the upper left of the board are there to adjust the sensor sensitivity.
More below the break.... Read More...
Also, in this article are a couple of movies that show a single-sensor alpha test on a climbing wall.
2 Lane, 4-sensor Perf-Board
Here’s a picture of the perf-board that contains the sensor detection and microcontroller interrupt logic for a two-lane speed climbing system. The microcontroller is on a separate board. The schematics for this board can be found in Part 5 of this series. The 4 orange potentiometers on the upper left of the board are there to adjust the sensor sensitivity.
More below the break.... Read More...
Speed Climbing Timing - Part 5 Schematics
03/06/2009 12:44
I took a short break from the prototyping workbench to catch up the project documentation. This one in the form of schematics. Using Eagle, I created a short set of schematics focused on various subsystems of the speed climbing timing system.
They are:
I won’t spend much time explaining the schematics. They could well change as I get further into this.
More below the break.... Read More...
They are:
- IR Sensor and Interrupt Logic
- Power Regulation
- Microcontroller Interfacing
- RJ45 pinouts for the Modular Connections
I won’t spend much time explaining the schematics. They could well change as I get further into this.
More below the break.... Read More...
Speed Climbing Timing - Part 4 Touch Pad Construction
02/25/2009 19:20
Synopsis: In Part 4, get a sneak peak of the mechanical design and construction of the sensor for stopping the clock at the top of a speed climbing route, the hand sensor. A video outlines the thinking behind the design and how it can work well for the climber and the routesetter to mount the sensor on the climbing wall.
Some of the critical requirements for this sensor are:
Robustness - it has to be able to take a direct, forceful hit by a climber’s hand. Often a climber will launch for the finish and smack the finish switch. It’s this behavior that has destroyed more speed climbing timing systems than any thing else. So, this touch pad has to be robust even though there’s no mechanical switch. A corollary to the robustness is safety. It has to be robust, but it needs to be safe for a climber to hit, even if he or she hits it very hard.
Assuming this IR light based sensor works well, climbers will quickly figure out they don’t need to practically destroy the sensor in order to stop the clock. The finish technique and behavior for finishing a speed climbing route will change to more finesse as a result.
Inexpensive - Another major requirement is the touch pad should be inexpensive to build. This mechanical and mounting solution uses easily attainable and inexpensive components from your local home improvement store. The sensors themselves are about $10 each (GP2Y0A21YK from Sparkfun), so there are $20 of sensors and about $10 of other materials for a total per-pad cost of about $30. For a 2-lane system, there are 2 touch pads for hands (one for each lane’s finish) and two base sensors for feet to detect false starts, so the system cost can get quite high if the per-pad cost isn’t kept low.
Easy to Mount - Finally, it had to be lightweight and easy to mount. This sensor, because it is installed at the top of the speed climbing route, needs to be ported up a ladder by a routesetter and mounted to the climbing wall. The solution presented is both lightweight and extremely robust and can be mounted with the standard climbing hold hardware - a 3/8” bolt. The bolt can be tightened as much as desired to keep the pad from moving on the wall without any damage to the sensor mounting hardware whatsoever.
Video below the break.... Read More...
Some of the critical requirements for this sensor are:
Robustness - it has to be able to take a direct, forceful hit by a climber’s hand. Often a climber will launch for the finish and smack the finish switch. It’s this behavior that has destroyed more speed climbing timing systems than any thing else. So, this touch pad has to be robust even though there’s no mechanical switch. A corollary to the robustness is safety. It has to be robust, but it needs to be safe for a climber to hit, even if he or she hits it very hard.
Assuming this IR light based sensor works well, climbers will quickly figure out they don’t need to practically destroy the sensor in order to stop the clock. The finish technique and behavior for finishing a speed climbing route will change to more finesse as a result.
Inexpensive - Another major requirement is the touch pad should be inexpensive to build. This mechanical and mounting solution uses easily attainable and inexpensive components from your local home improvement store. The sensors themselves are about $10 each (GP2Y0A21YK from Sparkfun), so there are $20 of sensors and about $10 of other materials for a total per-pad cost of about $30. For a 2-lane system, there are 2 touch pads for hands (one for each lane’s finish) and two base sensors for feet to detect false starts, so the system cost can get quite high if the per-pad cost isn’t kept low.
Easy to Mount - Finally, it had to be lightweight and easy to mount. This sensor, because it is installed at the top of the speed climbing route, needs to be ported up a ladder by a routesetter and mounted to the climbing wall. The solution presented is both lightweight and extremely robust and can be mounted with the standard climbing hold hardware - a 3/8” bolt. The bolt can be tightened as much as desired to keep the pad from moving on the wall without any damage to the sensor mounting hardware whatsoever.
Video below the break.... Read More...
Speed Climbing Timing - Part 3 Integration
02/21/2009 19:39
Synopsis: This is a video to show the initial integration of the IR sensors with the stop switch interrupt of the microcontroller. There’s more work to do as you will see. Later in the article are a couple videos which show the system working after an EMI issue caused spurious interrupts.
The basic integration of the IR sensors with the AVR is:
Video below the break....
Read More...
The basic integration of the IR sensors with the AVR is:
- IR Sensors have a high frequency component and the overall wave goes from about .8v to 2.5-3V.
- I take the IR signal into a low-pass filter to clean up the signal and remove the high frequency components
- That signal goes through a non-inverting comparator and amps the signal to the rail when the IR beam is reflected with a hand
- The output of the comparator goes to a hex inverter (74LS14) schmitt trigger
- The output of the schmitt trigger goes to the interrupt of the ATMega128.
Video below the break....
Read More...
Speed Climbing Timing - Part 2 Controller
02/19/2009 17:04
In Speed Climbing Timing Part 1, I introduced the touchless sensor concepts of a speed climbing timing system. In this part, I’ll demonstrate the basic controller and the timing functions as well as the display driver.
The display is based on a Maxim 7219 LED multiplexor. The controller is an Atmel AVR ATMega128. I’ve developed the Max7219 driver code and the basic timer to deal with a two-lane speed climber competition.
Read More...
The display is based on a Maxim 7219 LED multiplexor. The controller is an Atmel AVR ATMega128. I’ve developed the Max7219 driver code and the basic timer to deal with a two-lane speed climber competition.
Read More...
Speed Climbing Timing - Part 1 Sensors
02/19/2009 13:34
Most of my kids climb competitively and do an event called speed climbing. The name pretty much says what it’s about, but in general, 2 climbers go head-to-head on 2 25-50’ routes. After a climb is finished, they switch routes and climb again. The addition of the times of the two routes is the total time for the climber.
A problem that has plagued the event is the speed timing systems used are very unreliable. Most of these systems rely on some type of mechanical switch for the foot pedal and the top hand sensor to stop the clock at the finish, the top of the climber’s “lane”. Because the systems malfunction so frequently and can ruin the flow of the event and drastically extend the time it takes to execute the event due to re-climbing or fixing the system, I set out to design a system that did not use mechanical components. The goal is higher reliability, ease of installation, and also safety for the climber because sometimes mechanical switches have injured speed climbers hands.
Below is a video of a sensor concept I’m working on which will apply to the hand sensors at the top of the lane and the foot sensor at the bottom that’s used to detect a false start. These use an IR technology that’s relatively cheap (about $10 per sensor, 2 sensors per “pad.&rdquo
and immune to most IR emitted in ambient lighting situations. Read More...
A problem that has plagued the event is the speed timing systems used are very unreliable. Most of these systems rely on some type of mechanical switch for the foot pedal and the top hand sensor to stop the clock at the finish, the top of the climber’s “lane”. Because the systems malfunction so frequently and can ruin the flow of the event and drastically extend the time it takes to execute the event due to re-climbing or fixing the system, I set out to design a system that did not use mechanical components. The goal is higher reliability, ease of installation, and also safety for the climber because sometimes mechanical switches have injured speed climbers hands.
Below is a video of a sensor concept I’m working on which will apply to the hand sensors at the top of the lane and the foot sensor at the bottom that’s used to detect a false start. These use an IR technology that’s relatively cheap (about $10 per sensor, 2 sensors per “pad.&rdquo
and immune to most IR emitted in ambient lighting situations. Read More...asdfasdf
