The class …
doing experiments with materials, getting to know voltage or current,
Barbro creating a textile peltier element with constantin-copper connections in series, it provided around 30mV on a container with ice and your hand at the other side.
Maurin found a way to harvest energy with balloons. He made an LED flash with his contraption.
We started discussing energy harvesting using this page:
We did experiments with several materials, plastic, constantin-copper, and the underwear material.
Then we looked at the properties of a coil, to explain the “boost” of a boost circuit.
The first experiment was with a coil and a push button, where you get a flash when you let the push button go. This was improved with a ladder of aluminium strips replacing the pushing.
|http://etextile-summercamp.org/2016/wp-content/uploads/2016/07/Screen-Shot-2016-08-20-at-11.12.12.png 476w" sizes="(max-width: 300px) 100vw, 300px" />|
Then you let a transistor do the switching in the “Joule Thief”.
Some of the intermediate boost chips were presented: MCP1640 and NCP1400
both NCP1400 and MCP1640 on one 1.5V battery, driving a LED and an Arduino Pro, with a liquid LCD giving the voltage before and after using the analog PIN’s)
We touched briefly the concept of MPPT: (getting the max of power = V*I, within the max V and the max I range )
We also looked at “real” energy harvesting chips:
|LTC3109, for a peltier element – we showed it working on a block of ice, boost, low voltage to 3-5V||LTC3588, for a piezo element or a bigger solar panel (buck circuit, higher voltage to 3-5V)|
||LTC3105, for solar panels|