pic: Mousetrap car for engineering class

this is the mousetrap car i’ve built for one of my engineering classes.
it goes 18ft makes a 70deg left hand turn and goes another 18ft…
the goal was to do this in the shortest amount of time.

nice! can you give us more details on how it works? sounds like a fun, little project.

sorry for the short explanation, i had to run to class.

okay, here’s how it works

using rc car parts the front two wheels are setup with an ackerman system which is spring loaded to point them forward.

the back axle (which the string winds around from the mousetrap) is mechanically linked via small delrin chain to a piece of UMHW 1/4-20 threaded rod. This threaded rod has a small aluminum “trigger” on it that can’t rotate wit the rod hence when the back axle rotates its motion is transferred to linear motion of the “trigger” by the threaded rod.

as the “trigger” moves across the rod it hits a steering linkage at some point hence turning the wheels, and it pops past the linkage so the wheels return to straight.

and just for overkill i’m planning on having it stop right after it crosses the finish line just to show that i can lol

mission accomplished

sick, the only mousetrap I have ever built only had to go in a straight line. I like yours a lot better

What are your material limits and what kind of floor are you running on? If you can, and you wanted more traction for your CDs, you can take a balloon and cut an end off, and fit it around the edge. We did wooden mouse trap cars as a project my freshman year in IPC. I doubt you need the little traction it will add, but why not? :smiley:

Yeah, the same thing I had to do in H.S. As fast as you can go in a straight line across the cafeteria floor, no turning involved though. All we had to worry about was weight, friction and wheel diameter. Throwing a turn in the mix would have been more interesting. :slight_smile:

i am planning on putting a balloon strip around at least the back wheel and most likely all wheels, to avoid any spinning or skidding (as this would throw off the run).

Its running on a tile floor so the balloons will help


that is the car i made for my senior year physics class in high school.

as far as materials go we can use anything we can get, no cost limit just as long as nothings radioactive. And being part of the Iowa State solar car team, i am definitely making a carbon fiber spoiler simply because we have a large scrap pile of it…

i loved doing moustrap cars in my class! one problem i’ve noticed with the cd wheels tho, on cement or even tile, they tend to spin out a bit.

Geez, yours is intense compared to our classes. All we had to do was have it go exactly 10 feet, and then we had timed tests and tractor pulls for extra credit…and we were only allowed to use 1 mousetrap!

Ahh, Mouse trap powered engineering. We had to build a mouse trap powered string climber at UCSD. Object was to out climb the other entries. The day of the competition I put in a new and fresh mouse trap spring. Mine slammed itself into the ceiling on the first run and destroyed it self. :ahh: One run and I was out of competition but I was the only one to ever reach the ceiling. LOL

Ours projects was having to go 18ft power by the mouse trap…
I used K’nex wheels and axels that ran through holes in a 1/2 inch think piece of wood, where the mouse trap was hot glued on. And only usig a 1/8 piece of string about 2 ft long went the distance and sometime more…
I still have it and can take pictures to show off if anyone interested…
Also it would be nice to see some pictures of others…
(Idea a sperate mini mouse trap car races at FIRST events and mini awards for innvoation! :ahh:

Has anyone else had to do this project with a load added to the vehicle? I have my students design the vehicle around carrying a 12oz canned soda. I’ve dubbed it the “Can-Dew” challenge and it gives us a good excuse to buy a lot of soda and have a fun and stressful day trying to beat each other for distance. Rules are (1) Mousetrap as the sole source of power…only 4 holes in the Mousetrap allowed (for mounting purposes only) and other than that it’s pretty open to whatever they want to try.

yup! Our class is only allowed 1 mousetrap, no alterations allowed to the spring, flippy thingy mechanism, only allowed to take off the hook, locking mechanism for when the trap is set. (we just held the flipper thing down).

Anyways, we had to have a hook on our car so that a sled could be attached to it, the sled was light, and we would add weights at like 50g increments. Once the field was down to 2-3 cars, we would have larger increments until 1 of them showed signs of weakness. (pull distance was 5-6ft, cant remember)

And we are not allowed to have any soda:( We are in a computer lab

Mousetrap cars are awesome. Back in my day, the competition I did was scored as the product of the mass of the vehicle and the distance traveled. This being almost 15 years ago, I don’t remember the exact numbers, but most vehicles were somewhere in range of a few hundred grams. Mine was almost 2 kilograms (I used a large block of 2x4 as the main base). It also traveled the second furthest of all, probably somewhere in the 10-20 meter range.

Nice car, i like the design for turning!

we did mousetrap cars last year, the main issue was getting the car started cause the gear ratio was too high, so I build a CVT for mine :slight_smile:

It was basically just a wedge, and i wrapped the string around the bigger part to get the car started, then as it unwound it would go to the smaller part of the wedge to move to a higher ratio.

wow am i the only person who has never seen something like this before? i think this is great and im going to bring this up to my team and see if i can set up a school wide competition like this to try and attract more bright young members. thanks for the inspiration. nice car btw

Hey that competition idea is so much better than ours… the mousetrap car competiton in our class was only speed and distance based for the car traveling in a straight line. It would have been awesome to do a turn in there somewhere.

Looks neat. I never had to make mousetrap cars… We made CO2 cars in middleschool though.

In another class, we had to use a mousetrap to lift 3 different weights so far off the ground… but our device had to fit within X-amount of space. I do not remember if weight of the device was important… but I know materials cost was.

hence why the final was made out of carbon fiber as an upgrade
(eleanor is apparently a classmate thats disgruntled about losing lol)

Does the trap have to snap?

Because this would free up greater force over a longer period which you could increase via a small gear box vex would work, that would give you a bit more troque, but the trap probably has to snap, and a microgear box is most likely expensive, and or illegal…

thats about all i can suggest