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2 Posts tagged with the bicycle tag
1

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e-bike fleet (via austinevan)

 

In the City of San Francisco, going for a bike ride is exceptionally picturesque. But the steep hills may deter the non-enthusiasts from using their bikes as a viable means of transportation. A solution that lessens the physical stress and could influence some to take on biking is making electric bikes available for rent. The car sharing program City CarShare, in San Fransisco, plans on making 45 e-bikes available for daily rentals by the end of this year and 45 more in 2013. The program is receiving funds from the Federal Highway Administration’s Value Pricing Pilot Program, which is aiming at lowering traffic, pollutions and dependence of fossil fuels by variable pricing, meaning that prices can be bargained or negotiated.

 

 

The San Francisco Metropolitan Transportation Agency received 1.5 million dollars, $760,000 of which will go to the City CarShare program to fund 40% of the cost for 90 e-bikes scattered in 25 locations for three years.

 

 

The cost for renting a bike will be 50-70 percent lower than renting a car. Currently, customers pay as little as 5 dollars per hour and a monthly fee of 10 dollars for cars. City CarShare wants to make convenience their first priority before profit. Since bikes will be required to be returned to their original stations, City CarShare explained they will make low fees for keeping it over night to lessen the financial burden and increase convenience.

 

 

The other part of the funding will be devoted towards answering when and why individuals chose to rent out e-bikes instead of cars. The research will be conducted by UC Berkley and will attempt to analyzing the long term impact and performance of the project. Bike rentals are not unheard of, but the company City CarShare is venturing into new territory by offering e-bike and car rentals. The outcome of this trial is sure to influence other cities and companies to take on similar programs.

 

 

I would like to see this e-bike rental program to spread. There have been so many times where a e-bike would have been so useful for commuting in my city. I just do not want to buy and house a $300+ dollar bike at the moment. Hence, why I want to make one.

 

 

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0

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Professor Holger Hermanns and the wireless brake system (via Saarland University)

 

What is 99.999999999997 safe and has a 250 milli-second delay? It is the wireless bicycle brake from Saarland University. Professor Holger Hermanns, lead designer on the project, had this to say about the reliability, "... out of a trillion braking attempts, we have three failures. That is not perfect, but acceptable."

 

With pressure sensors in the bicycle's grips, the rider has to just squeeze. The system interprets how hard the person in squeezing, and adjusts the brake's clamping power proportionately. The transmitter, blue box on the handle bars, relays the signal to the breaking apparatus. The system uses a TDMA-based communication link (2.4GHz ISM band, MyriaNed wireless node). Each node is run with an Atmel atxmega128A1 and a Nordic Semiconductor NRF24L01G+ transceiver. According to the design team, adding additional signal repeaters does not increase the reliability. 

 

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The clamping force is applied with what looks to be a stepper motor or large solenoid. The power demands of a stepper motor would be less strenuous, so I am leaning in that direction. Either way, the team stated that making a anti-lock brake system is entirely possible. Right now the team is more focused on defeating the 250milli-second delay. As they stated, "Its current configuration enables the cruiser bike to brake within 250 milliseconds. This means that at a speed of 30 kilometers per hour, the cyclist has to react two meters before reaching the dangerous situation."

 

Looking for a job in Germany? Professor Hermanns is looking for engineers who understand his concept of wireless braking to help with his efforts. The project is funded by the German Research Foundation under the "Automatic Verification and Analysis of Complex Systems (AVACS)" label. Read more about the fundamentals and technology behind the wireless brake in Professor Hermanns's paper, "A Verified Wireless Safety Critical Hard Real-Time Design." Note the file name, "wowmom.pdf."

 

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