Forum Noob Looking for Pinewood Derby Assistance
LFransen
Posts: 9
Hi everyone,
I was recently direct to this forum and these products by a coworker. We were talking about how to biuld a Pinewood Derby Sequence of Finish timer for an old track we have when he suggested this might help. I dug through what I could find and there are two old threads that are related to what I am doing:
http://forums.parallax.com/showthread.php/102321-Inferred-start-finish-line-detector-with-timer.-For-co2-cars!!!?highlight=pinewood+derby
http://forums.parallax.com/showthread.php/136035-Race-timer?highlight=pinewood+derby
Like user arend in the second post what I am looking to do is this:
Make a Sequence of Finish timer that uses:
-A control switch at the top of the track at the start gate to signal the beginning of the race (mechanical)
-Set IRLEDs and photo sensors at the finish line for either 6, or preferably 8 lanes. IRLEDs and the bottom and Photo sensors in tubes above them.
-Set up a simple 7 segment LED display (2-4" tall) that shows what order the cars finished in above each lane (6 or eight displays in total)
Mostly what I have been finding is timer circuits which could work in place of SOF, but I want to keep it simple. One idea I had previous to this was building 8 simple digital stopwatch circuits (one for each lane), and tying the start and reset functions together. The hard part was the finish line circuit that would stop the timer count as each car passed over a sensor. The designs I saw were simple in that the start/stop functions were one and the same which would work for me. This is why my coworker suggested the Propeller. I've seen similar ideas on Youtube for Arduino based systems but nothing to handle 8 lanes for cheap.
So, for the group, is this something the Propeller could do? I am more than capable mechanically, and electrically and have some programming knowledge. If I were to got his route what do you think I would need?
I know some things would be:
- 6 or 8 sets of IRLED/Phototransistors
- Start switch
- Reset switch
- Structure for the finish line sensors
- 6 or 8x seven segment LED displays
Any help would be great.
Len
I was recently direct to this forum and these products by a coworker. We were talking about how to biuld a Pinewood Derby Sequence of Finish timer for an old track we have when he suggested this might help. I dug through what I could find and there are two old threads that are related to what I am doing:
http://forums.parallax.com/showthread.php/102321-Inferred-start-finish-line-detector-with-timer.-For-co2-cars!!!?highlight=pinewood+derby
http://forums.parallax.com/showthread.php/136035-Race-timer?highlight=pinewood+derby
Like user arend in the second post what I am looking to do is this:
Make a Sequence of Finish timer that uses:
-A control switch at the top of the track at the start gate to signal the beginning of the race (mechanical)
-Set IRLEDs and photo sensors at the finish line for either 6, or preferably 8 lanes. IRLEDs and the bottom and Photo sensors in tubes above them.
-Set up a simple 7 segment LED display (2-4" tall) that shows what order the cars finished in above each lane (6 or eight displays in total)
Mostly what I have been finding is timer circuits which could work in place of SOF, but I want to keep it simple. One idea I had previous to this was building 8 simple digital stopwatch circuits (one for each lane), and tying the start and reset functions together. The hard part was the finish line circuit that would stop the timer count as each car passed over a sensor. The designs I saw were simple in that the start/stop functions were one and the same which would work for me. This is why my coworker suggested the Propeller. I've seen similar ideas on Youtube for Arduino based systems but nothing to handle 8 lanes for cheap.
So, for the group, is this something the Propeller could do? I am more than capable mechanically, and electrically and have some programming knowledge. If I were to got his route what do you think I would need?
I know some things would be:
- 6 or 8 sets of IRLED/Phototransistors
- Start switch
- Reset switch
- Structure for the finish line sensors
- 6 or 8x seven segment LED displays
Any help would be great.
Len
Comments
Here's a video of the prototype
I posted a blog entry with the source code:
http://forums.parallax.com/entry.php/3396-My-Pinewood-Derby-Prototype
Note that due to forum migration the code needs a pretty printing, and it was written using the beta Arduino libraries. It might need some tweaks to work on the modern IDE.
I do like the simple design. I know the kids would love to be able to see some kind of display because, well, kids want to win. That being said, is this something that could be scaled up to 6 or 8 lanes? For the finish lines sensors I am assuming you are using the overhead ambient light for the photosensors?
I can't see the link you posted, for some reason it is saying I don't have any rights.
Thanks!
Len
Note that this design is really simple and could work with either an Arduino or Propeller chip as both of them have internal tick counters that can be used to time events. Only a little of the code interacts with the Arduino library and it would be easy to replace with native propeller C equivalents. Electrically it's two push button detection circuits, a three pin able for the servo, and a bunch of either CDS or photocells to detect the light transition.
The first circuit is one to detect push buttons to start and stop the race: http://learn.parallax.com/propeller-c-simple-circuits/check-pushbuttons
The second is one to sense a change in light levels as the car passes overhead: http://learn.parallax.com/propeller-c-simple-circuits/sense-light
The final circuit is connecting the microcontroller to a display device like an LCD panel. That's less of a circuit and more just connecting the output of six pins into the correct leads of an LCD panel. HEre's an example in Spin http://tymkrs.tumblr.com/post/87994050098/parallel-lcd-propeller-and-in-spin
Thanks!
Can't read the linked page.
you do not have permission to access this page. This could be due to one of several reasons:
Your user account may not have sufficient privileges to access this page. Are you trying to
edit someone else's post, access administrative features or some other privileged system?
If you are trying to post, the administrator may have disabled your account, or it may be
awaiting activation.
LF, I'm guessing the lanes are flat black? at least at the finish line.
So the light reflecting off of the cars would be what the photo transistor sees happen.
I think Parallax still carries the serial LCD display Fewer pins used for that and simple software.
But a great big seven segment display counting tenths of seconds could add something to the excitement level.
Maybe even a big bright LED over the winners lane?
Could be a fun project.
Try to get a newer phone or camera with slow-motion for recording races from overhead at the finish line.
120 fps should be good enough for photo-finish confirmation if there are any questions.
Then you can display much more information and have color also.
Bean
The forum is sill going through some upgrades. The Blogs will not be available during this time.
Koehler- We've been using video in the past but it takes time. as you know kids have little patience so we like to keep things rolling.
A simple single digit LED above the finish line indicating finish order is the simplest. A timer showing time elapsed is also good.
http://www.microwizard.com/k2page.html
http://www.pinewood-derby-timer.com/home.html
Again, the problem is cost. an eight lane system costs many hundreds of dollars.
Len
Add $20.00 for a propeller proto board and about $20.00 for a 9V 1A power supply and the total is about $200.00 not including any shipping costs. A little scrounging might even reduce that some.
1 - Start gate switch
1 - Long cable from start gate back to controller
1 - Propeller board
1 - Reset switch
1 - 5VDC power supply
6 or 8 - sets of IRLEDs/Phototransistors (depending on whether I make this for 6 or eight lanes)
6 or 8 - LED displays
Wire or cabling for the sensors back to the controller
various resistors and such
Seeing as I have never used the Propeller products I am not sure all I would need or exactly how this would work. Any further ideas? Circuits, etc.? Thanks for the help thus far!
As a starting point I looked at the following parts:
1 - Start gate switch: starts the timers when closed, resets system when open.
1 – Propeller Project board: system controller.
1 – 9VDC 1Amp power supply.
10 – Led displays and drivers
10 – IR receivers and leds
10 – Voltage regulators
8 – Pad per hole circuit boards
FYI, Buying 10 pieces for some of the parts is less than buying 8.
BTW, if you had an extra monitor you could use for this it would make for a less costly and more capable system.
Here's a copy of my timer code for the Arduino. It should be easy to port to the prop either by replacing the Arduino library calls with their Propeller equivlents or using my own library: https://code.google.com/p/lib-propelleruino/ which reimplments many of them.
So this first thing I need to do is decide the output mechanism (LED display or LCD)
I also need to decide on time display or finish order.
Aside from the programming logic of deciding finish order I think I have quite bit to start on.
So the last thing I am wondering is if the Propeller has a sufficient number of I/O to handle this. I would need 6 or 8 for the lane sensors, Start gate, reset function, and output to drive the LED displays or LCD. Th other option is maybe the Arduino Leonardo. Seems to have a lot of I/O capabilities.
[video=youtube_share;iydnohrqCBQ]