Energy Harvesting Prototyping Challenges
One important aspect of tinkering both for learners trying activities and developer working on new projects and prompts is that oftentimes there’s not a clear endpoint in sight at the start of the process. This makes things exciting and opens up possibilities for new and surprising results but it can also be a challenge especially when things don’t work out as expected.
Over the past few months I’ve been involved in a prototyping process to develop a new exhibit on energy harvesting with Phaeno Science Center in Wolfsburg, Germany that has contained lots of this type of failure and frustration. I wanted to share some notes from this “unsuccessful” project to highlight the ways to work through difficulties, identify moments of learning and ask for help to uncover future directions.
In this project we’re hoping to develop a playful and learner driven way for museum vistors to explore energy harvesting, where ambient energy from sources like vibration, solar, wind or temperature gradients can be used to give power to small electronics. Because the exhibit would be inside we’re not considering solar or wind elements and we’d like to focus on posibilities for “passive” harvesting of electricity that doesn’t involve hand-crank or pedal generators as those are already common science center exhibtion elements.
The collection of parts that I’ve been working with include three possible ways to approach the theme. They are battery-less bluetooth switches that use the motion of flipping the switch to activate the electronics, peltier elements which produce energy when there’s a temperature difference between the sides and piezo microphones which provide electricity when vibrated. Some of the other elements that I collected were LEDS (red ones seem to be the easiest thing to power), a multimeter, other electronics elements like capacitors, diodes and rectifiers and alligator clips.
The first challenge arose when dissected the bluetooth switch. The mechanism and electonics look very cool even if they are a bit difficult to understand. Unfortunately I couldn’t just plug in battery powered electronics to the receiver as it required wall power to function. I don’t like tinkering with that amount of current so it put an end to the explorations for the moment. It also highlighted a more general issue with many of these parts that since the energy generation is low they often have to interact with other components that are powered by batteries or being plugged in. This could be a bit confusing for participants if it’s not clear what part of the system is harvesting electricity.
The second element that didn’t work as expected was the peltier units. They should give power when there’s a temperature difference between the sides but I couldn’t light an LED event when adding an ice pack to one side and a flame to the other. Perhaps the sides need to be better insulated or have a custom heatsink installed so that the gradient stays more consistent.
The elements that produced a bit of a reaction were the piezo microphones. When attached to a LED (with or without a capacitor) tapping on the piezo gave a momentary flash of the red light. But of course there were still challenges as this small burst of power doesn’t feel too impressive and is hard to connect to the real life situations.
Some of the things that we tried were making an array that could respond to kids jumping, building a track for a specialized wooden car and hooking up several piezos to a rod that could be rocked back and forth. These experiments had varying degrees of success but all faced the same issue that we couldn’t find a way to connect the piezos together that clearly amplify the signal and all ways of interacting with the components risks breaking these fragile parts. Future experiments will work on addressing these issues as well as finding ways to make the interaction more fun and the output more compelling.
In the time-honored tinkering tradition of trying things out with the public when there are still under development, the team from Phaeno will set up a facilitated table with two of the piezo circuit boards for people to explore next week during a school holiday. Hopefully that process will lead to new ideas and as well I hope that sharing these challenges and frustrations here on this blog will lead to more collaborations with artists, makers, tinkerers and educators who can suggest new directions.