I've built some fast pinewood derby cars in the past but this year was just about looking good. I've always loved the way those lowriders bounce and thought it would be cool to make a derby car do that. Here's my version. A few more pictures and build details after the jump.
Here's the first iteration of 'Scout'. A simple printable frame for a robot based on two continuous rotation servos and an Arduino.
The idea was to limit the number of printable parts and 'vitamins' to the bare minimum and keep the total cost for the bot below $50. I'll use this to teach the robotics merit badge in December. Here's how the costs breaks down:
- 2 Futaba S3003 servos or equivalent (modified for continuous rotation). $4.50 each. I found deals on ebay to buy sets of 4 for $16 with no shipping.
- 1 arduino diecimila. $20 - 25. Also an ebay deal. A nano may work better. I'm still looking into this.
- 3 o-rings for tires. $3.00. Might be possible to replace these with rubber bands.
- 9V battery
This year we built a casket on wheels. Both parts of the lid are hinged and it carries a 'Gummy' skeleton as a rider. Obviously he had adult help on this design. The main parts were cut out on the CNC router. But you might be surprised how much he did himself:
- Sanding (They say sanding builds character )
- soldering the rails together with the torch (close supervision)
- Staining and sealing
- polishing axles.
- Shaping, sanding, lubing wheels.
- Testing weight.
The final assembly and alignment we worked on together.
Ross also enjoyed correcting adults who referred to this as a coffin.
It's fun to see the boys progress from doing very little as tigers to doing almost everything as Webelos. Our shelves are really filling up with some cool cars and 'Deathtrap' joins a distinctive collection.
Pictures of the other cars after the jump.
It's Pinewood Derby season again and I kinda enjoy making derby cars. This year, my youngest son and I made an awesome car for his bear den division. It came out great and I'll do a blog post on that one as soon as I get some good pictures.
We also have an 'open' class where the rules are a little more relaxed. Last year's car was fast and I actually won but not because I was the fastest. I was really impressed by a c02 powered car that another dad had made. He had trouble keeping it on the track, but it was REALLY fast.
Our local cubscout pack has an "open" class meaning Dad's, siblings, Mom's or others are welcome to participate. I helped my boys build their cars and then built mine. My goal was to design the whole thing in CAD and machine it on my router. I ended up using the pocket operation to cut a recess in the bottom to accept the weight and a zigzag operation to cut the basic shape.