Pack 45's Pinewood Derby Homepage

Race Day February 11, 2017
 
The Derby will be held at the Richard W Black Center (RWBC), a.k.a. Hanover Recreation Center. Weigh-ins start at 6:00pm, racing starts at 6:30. This is a family event so bring the grandparents, uncles, cousins, and anyone else who might enjoy the race.

 
"Be Fast... or Look Good Trying"

The pinewood derby is one of the most popular and successful family activities in Cub Scouting. Pinewood derby cars are small wooden models that Cub Scouts make with help from their families. Then they race the cars in competition. The cars are powered by gravity and run down a track. Every boy can design and build his own "grand prix" car to enter in the race.


 

Prizes and Recognition


The Derby is about doing one's best and having fun, so all child participants will be recognized.  But that doesn't mean our race winners won't take home some shiny hardware. 

Derby Workshops

There will be several opportunities to mold and shape the block of pinewood into a mean lean well-decorated racing machine.  We will announce dates and times for the workshops once we get the parents lined up who will be supervising the shop tools.  The boys are encouraged to design the shape of their cars, sand them, and decorate them accordingly. They are permitted to use certain power tools (e.g. mandrel on a cordless drill) under close supervision. Other power tools such as a bandsaw or scroll saw should be handled by adults. Parents are encouraged to assist the child but they should let the child do most of the work.

Equal Ground

All entries in the derby will start with the "Official Grand Prix Pinewood Derby Kit" which includes the body, 4 axles, and 4 wheels.  All nine pieces from the kit (or from a BSA approved kit) MUST be used before the car can race. The kits are supplied by the Pack, and BSA-approved kits, parts, and tools are also available at local stores such as Hobbies 'N Stuff in West Lebanon. All active Scouts will receive a kit in plenty of time to build it before the race. Cars may not exceed 5.00 ounces in weight and must conform to certain size restrictions and specifications. Decorating the cars are up to the imagination of the boys. The complete set of rules are available below. 
 
Printable Rules
 
Here are the printable rules for the 2017 Pinewood Derby.


Pinewood Derby Timer Construction


In 2013, Wayne Chin decided to build an electronic finish line for Pack 45.  Here's the story of the project that became a great success!

Parts arrived. Includes Arduino Uno R3, Adafruit Protoshield, and 4 Adafruit LED I2C backpacks.
 Pinewood Derby Timer parts
 
Soldered the displays, soldered headers onto the Protoshield, and uploaded the PDT software into the Uno. A simulated test run yielded an elapsed time for Lane #1.
Soldered ID jumpers on each of the LED backpacks.
 
Setting IDs
 
Wired up with IR illumination LEDs (pointing downwards from platform), photo detectors (at the ends of the long cables), and re-purposed laptop power supply (not shown). Platform has 7" clearance, and can be adjusted up/down up to 2" if needed. Frame is leftover birch from a basement remodel. Display bar is leftover cherry cabinet trim.
Drilled holes in track for photo detectors and verified that wire lengths are sufficient. Track needs to be elevated for photo detector wires to clear. 
 
Looking for a good way to mount the start gate switch.
Completed and working its first race. Here it is displaying the elapsed time for each lane at the end of a race heat. 
 
Here's a picture of another race heat in progress where three cars have already crossed the finish line, and the last car is just passing over the sensor.

Pinewood Derby Timer Technical and Purchasing Information

Pinewood Derby Timer: http://www.miscjunk.org/mj/pg_pdt.html
Arduino Uno Rev 3: http://www.abra-electronics.com/products/A000066-Arduino-Uno-Rev-3%252d-official-Made-in-Italy.html
Adafruit Proto Shield for Arduino Uno: http://www.abra-electronics.com/products/51-Adafruit-Proto-Shield-for-Arduino-Kit-%252d-v.5.html
Adafruit 7-segment I2C Backpack: http://www.abra-electronics.com/products/880-Adafruit-0.56%22-4%252dDigit-7%252dSegment-Display-w%7B47%7DI2C-Backpack-%252d-Green.html
Infrared LED emitter and photo detector pair: http://www.radioshack.com/product/index.jsp?productId=2049723, or also from Ebay
Photo transistor: http://www.radioshack.com/product/index.jsp?productId=2049724, or also from Ebay
5mm LED bezel/holder: http://www.radioshack.com/product/index.jsp?productId=276080, or also from Ebay

Taiwan Oasis TOPS-050 (datasheet is A-1542.pdf below) - Phototransistor, 900nm, black 5mm package
Vishay TSAL7400 - IR LED, 940nm, clear 5mm package, +/-25 deg beam (driven with 75-ohm bias resistor at about 50mA each, or about 20mW of IR output each - hopefully they will last a long time at this power output level)
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Wayne Chin,
Jan 20, 2013, 4:11 AM
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Charles Palmer,
Jan 18, 2014, 6:33 PM
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Wayne Chin,
Jan 30, 2013, 8:05 PM