Power Generation
Modern exercise equipment has the ability to operate at any time of day, provide workout details (heart rate, mph, calories burned, etc), and charge cell phones. As a piece of exercise equipment, the Assisted Jogger should have these same capabilities.
Factors that were considered in the chosen part were power produced at low speeds, the drag produced at low speeds, and the reliability. The power produced at low speeds is important to our design because the Assisted Jogger won’t be traveling at speeds of a bicycle. Based on the electrical components the Assisted Jogger has, a minimum power of 4.5 watts is required. The drag produced at low speeds is also important to our design, because the Assisted Jogger cannot be hard to push. When on a bicycle it is hard to notice the drag, due to the large force acting on the hub and the momentum. When using the Assisted Jogger, not as much weight is located over the hub, causing drag to be a concerning issue. The figure below, shows the power generated from various dynamo bicycle hubs at 5 mph.
Based on the graph, all dynamo hubs create between 4 W and 5 W. As stated above, the Assisted Jogger needs 4.5 W. This makes the SON 28 the only dynamo that can safely guarantee the required power. The figure below, illustrates the drag produced from various dynamo bicycle hubs at 5 mph.
Based on the figure above, the SON 28 and the SON delux produce half the drag as any of their competitors. Again it doesn’t seem like much, but it’s a noticeable difference to a runner. The SON delux is a better fit for this issue, but it isn’t easily compatible with 700 cc rims, which is needed for our frame design. The SON 28 is the best design, for what the Assisted Jogger is trying to achieve. The SON 28 also has high quality bearings and a system to prevent moisture and corrosion, which is important for reliability. A picture of the SON 28 is pictured below in the figure below
Electrical Components
While exercising at night, it is important to be able to see the road ahead, and to be seen by others. Lighting for the Assisted Jogger is important for the rider’s safety and so it can be operated at any time of day. The lighting for the Assisted Jogger includes a front headlight, and a rear taillight.
Options for the front headlight were LED, and halogen, which are the only two lighting systems that are compatible with a dynamo bicycle hub. Factors that influenced our chosen light include the required power to operate, required speed for full illumination, and reliability of light. Because the Assisted Jogger operates at low speeds, halogen light bulbs are not the best option. At low speeds, halogen light bulbs will flicker and a speed of 5.5 mph is required for full illumination. LED lights reach full illumination at speeds under 2mph and require 2.4 watts compared to the 6 volts required by the halogen bulbs. The lifespan of LED lights are 10 times greater than halogen bulbs and will not flicker until it reaches 20 % of its rated power. Based off the information gathered, it was evident that the Assisted Jogger needed an LED light. A light known as the Lumutec Plus, built by Busch and Muller was the chosen part for our design. The picture below shows a picture of the chosen light.
Options for the front headlight were LED, and halogen, which are the only two lighting systems that are compatible with a dynamo bicycle hub. Factors that influenced our chosen light include the required power to operate, required speed for full illumination, and reliability of light. Because the Assisted Jogger operates at low speeds, halogen light bulbs are not the best option. At low speeds, halogen light bulbs will flicker and a speed of 5.5 mph is required for full illumination. LED lights reach full illumination at speeds under 2mph and require 2.4 watts compared to the 6 volts required by the halogen bulbs. The lifespan of LED lights are 10 times greater than halogen bulbs and will not flicker until it reaches 20 % of its rated power. Based off the information gathered, it was evident that the Assisted Jogger needed an LED light. A light known as the Lumutec Plus, built by Busch and Muller was the chosen part for our design. The picture below shows a picture of the chosen light.
This light comes without a switch, but a switch was added to the circuit to control when it is on and off. For the taillight, it was decided to use a LED light that operates off small batteries compacted within the unit. This will eliminate wire running from the front to the back of the frame. The remaining power from the dynamo bicycle hub can then be used to charge the battery.
Like other modern exercise equipment, the Assisted Jogger needs to have the ability to charge devices such as smart phones, and GPS. Most of these devices require a constant voltage to charge, which is an issue, due to the fact that all dynamo bicycle hubs produce alternating current. Possible solutions to this issue are using a device called an e-work, or by using a full-wave bridge rectifier. The e-work is a device that controls the voltage and current levels. The full-wave bridge rectifier consists of four diodes that switch polarity every half cycle. This make the voltage always positive (DC current), but loses power in the process. The e-work has a much better performance but it is also more expensive. The plan is to use either of these devices with a battery, so energy isn’t wasted when the Assisted Jogger is being used without a cell phone charging or when the light isn’t being used. This stored energy can be used to power the light when the user decides to take a break at nighttime. Also some smart phones require a constant voltage to charge. At different running speeds, the amount of voltage is going to change. The battery will be able to give these devices the constant voltage that they are looking for. The battery for this design is still being looked into.
Like other modern exercise equipment, the Assisted Jogger needs to have the ability to charge devices such as smart phones, and GPS. Most of these devices require a constant voltage to charge, which is an issue, due to the fact that all dynamo bicycle hubs produce alternating current. Possible solutions to this issue are using a device called an e-work, or by using a full-wave bridge rectifier. The e-work is a device that controls the voltage and current levels. The full-wave bridge rectifier consists of four diodes that switch polarity every half cycle. This make the voltage always positive (DC current), but loses power in the process. The e-work has a much better performance but it is also more expensive. The plan is to use either of these devices with a battery, so energy isn’t wasted when the Assisted Jogger is being used without a cell phone charging or when the light isn’t being used. This stored energy can be used to power the light when the user decides to take a break at nighttime. Also some smart phones require a constant voltage to charge. At different running speeds, the amount of voltage is going to change. The battery will be able to give these devices the constant voltage that they are looking for. The battery for this design is still being looked into.