G+_Walter L. McCormick Posted September 7, 2015 Share Posted September 7, 2015 Hi everyone, so I am in my intro to engineering design course and my group's project is to take a 3d printed model car frame and attach a motor and solar cell to the car. Once the whole class has their cars built we are going to race them. They have to go 20 feet on a flat concrete sidewalk. We are allowed to modify the 3d print any way we want, but only are only allowed $25 to buy the solar cell, motor and any other component we want. We cannot however use any form to store energy. So no batteries or capacitors. Does anyone have any suggestions for me? I am not looking for someone to do my work, I just want suggestions from anyone who may have done this before. Thanks! Link to comment Share on other sites More sharing options...
G+_Fr. Robert Ballecer, SJ Posted September 7, 2015 Share Posted September 7, 2015 Storing ENERGY is not allowed... or storing ELECTRICITY? It makes a difference for us mad scientist types. :) (Think... flywheel) Link to comment Share on other sites More sharing options...
G+_Eddie Foy Posted September 7, 2015 Share Posted September 7, 2015 high voltage / low current. DC motors like to spin fast. 20 feet? who cares if you burn out the motor. put many tiny panels in series. Link to comment Share on other sites More sharing options...
G+_Eddie Foy Posted September 7, 2015 Share Posted September 7, 2015 Solar panel to ignite a model rocket engine? Link to comment Share on other sites More sharing options...
G+_Walter L. McCormick Posted September 7, 2015 Author Share Posted September 7, 2015 No storing of energy. "The only source of energy to move the car will come from the sun through the solar cell" - project instructions I was also thinking flywheels but she shot that theroy down. Link to comment Share on other sites More sharing options...
G+_Eddie Foy Posted September 7, 2015 Share Posted September 7, 2015 a Fresnel lens over the panels will increase output. Link to comment Share on other sites More sharing options...
G+_Walter L. McCormick Posted September 7, 2015 Author Share Posted September 7, 2015 Great suggestions Eddie Foy I assume the fresnel lens needs to be adjusted to the focal point to maximize efficiency?? Off to the drawing board!! Link to comment Share on other sites More sharing options...
G+_Fr. Robert Ballecer, SJ Posted September 7, 2015 Share Posted September 7, 2015 Any chance we could get a link to the STL file? A few quick suggestions: 1. Invest in ball bearings and low rolling-resistance wheels. -- Makers often focus on power and miss the fact that KEEPING that power in the system is usually more important. 2. Try using a 1s or 2s rated outrunning motor. Their RPM is lower, but their torque if phenomenal. You can probably do direct drive, lowering on-board weight and increasing efficiency. 3. If you can modify the 3D print, take out ALL the structure you can without compromising the integrity of the vehicle. Link to comment Share on other sites More sharing options...
G+_Walter L. McCormick Posted September 7, 2015 Author Share Posted September 7, 2015 Fr. Robert Ballecer, SJ? I should have mention this before. The 3d printed models are already printed by the professor. We are allowed to cut/sand the models if we decide to. Though I do not know how smart an idea that would be. Keeping the weight low as possible was what I was thinking aswell. Link to comment Share on other sites More sharing options...
G+_Walter L. McCormick Posted September 7, 2015 Author Share Posted September 7, 2015 Do you think it is safe structurally to take a Dremel tool with a cut off wheel and trim the model down? My fear is that since the print is done in layers if I cut parts off it may want to de-layer itself. Link to comment Share on other sites More sharing options...
G+_Dave McCormick Posted September 7, 2015 Share Posted September 7, 2015 http://www.allelectronics.com/make-a-store/item/spl-61/solar-cell-60mm-x-60mm-x2mm/1.html Link to comment Share on other sites More sharing options...
G+_Dave McCormick Posted September 7, 2015 Share Posted September 7, 2015 Without seeing the printed structure it is hard to say how much material you can remove. Is it printed with ABS or PLA? Link to comment Share on other sites More sharing options...
G+_Walter L. McCormick Posted September 7, 2015 Author Share Posted September 7, 2015 Pretty sure its ABS. I'm not 100% positive. Link to comment Share on other sites More sharing options...
G+_Walter L. McCormick Posted September 7, 2015 Author Share Posted September 7, 2015 This is the one I was looking at. http://www.amazon.com/gp/product/B007Z7TWVO?psc=1&redirect=true&ref_=ox_sc_sfl_title_3&smid=AX9W1G1X8SWR2 Link to comment Share on other sites More sharing options...
G+_Dave McCormick Posted September 7, 2015 Share Posted September 7, 2015 Looks like a good cell. With ABS you will want to have some acetone handy if you make a mistake modding. Link to comment Share on other sites More sharing options...
G+_Eddie Foy Posted September 7, 2015 Share Posted September 7, 2015 Could use the panels as wings to make the car 'lighter' Link to comment Share on other sites More sharing options...
G+_Jim Sauber Posted September 7, 2015 Share Posted September 7, 2015 Since you can't add modify the design with bearings, use very fine sandpaper (1000 grit) to smooth any surfaces where there is friction like the axles. Then, lubricate with a dry lubricant like graphite (Find a pencil and sand the lead to save yourself on the budget). Link to comment Share on other sites More sharing options...
G+_Black Merc Posted September 8, 2015 Share Posted September 8, 2015 tortoise and the hare? Is it really speed that you need? A thought... Link to comment Share on other sites More sharing options...
G+_Jeff Brand Posted September 9, 2015 Share Posted September 9, 2015 The way I read it, the only "source" is solar power. That doesn't address storage at all, as long as they're empty at the start. For example, you can't start with a wound rubber band, but could wind it through solar power, used later. Link to comment Share on other sites More sharing options...
G+_Walter L. McCormick Posted September 9, 2015 Author Share Posted September 9, 2015 I did clarify with her and she said the solar cell has to directly power the motor. No storage can be used in between. Link to comment Share on other sites More sharing options...
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