We have always been in close contact with plants, trees, flowers, shrubberies, grasses, weeds and other vegetation, yet we have never figured out how to communicate with them. They are alive, we know that, but what do they think or how do they feel? Clueless, we created Bio-Light to visualize our green friends’ emotions.Let’s start this article by making it very clear that we do not claim omniscience about the secret emotional life of plants. In fact we don’t even know if they have one. All we know is that plants produce electrical signals and — being electronics engineers — we know everything about electrical signals and what to do with them. Although we have no idea how to interpret the electrical signals produced by plants, we should be able to make them visible with full-colour LEDs. That is what Bio-Light is, a device that visualizes electrical signals (biosignals) generated (we think) by plants.