Making Community Gardens Sustainable is an ongoing theme of this blog and of the work I do during the time when I am not blogging. My most recent project was to devise a human powered water pump using a bicycle. Most community gardens do not have access to electricity to power a pump. A few might have solar panels to run lights or power other devices. Some may have access to electricity from the grid. But the numbers for electrified community gardens is small. Other solutions are necessary for the task of pumping water. I have already worked with an engineering intern to design a treadle pump for pumping water. An earlier blog post describes that effort.
I felt this was a good solution but that creating a pump that worked with a bicycle might be even better for a number of reasons. Most people have a bicycle available to them and there are many used bicycles available for little or no cost. Bicycles and riding a bicycle are also more familiar to most people than a treadle pump. The bicycle could be used as a method of transport when not being used to pump water. Much like the treadle pump, using the bicycle to pump water would also be a form of exercise - a side benefit of this project.
There are some notable efforts at devising human powered machines. In most cases these efforts are being done in developing nations by international aid organizations or students. A very interesting group is Maya Pedal in Guatemala. They have devised many pedal power machines including corn grinders, nut shellers and wood saws. Youtube has many videos of bicycle powered devices, most often showing ways to generate electricity using a bicycle. That was one direction to work on but I wanted to use the bicycle to drive a pump directly rather than to produce electricity to run the pump.
One idea I had was to use a drill pump. A small inexpensive device that can be attached to a power drill to pump out water in basements, swimming pools and other home uses. I just had to figure out a way to transfer the motion from a bicycle wheel to the drill pump. My first attempt was to use a bicycle blender setup to turn the drill pump instead of a blender. I made a prototype which worked but seemed like too much power was lost doing it this way.
I then realized that the bicycle trainer that kept the rear wheel off the ground could be adapted to turn the drill pump directly. I made a video that explains how it is done. I have to secure the drill pump and connector pieces better. In the video you will see that the pump is held in place by wires as a temporary solution. I will create a frame of some kind to secure the pump to the bicycle trainer. So it will be one unit easily moved or stored.
This is one small project that along with a number of other small projects can help make community gardens sustainable. With a little funding, hopefully several community gardens that can most use a bicycle water pump for their Rainwater Harvesting systems will get them this coming spring.