Low-resolution lighting displays are commonplace in internet-of-things devices, wearable products and embedded interfaces. However, prototyping such displays is challenging and cumbersome as methods, specific domain knowledge and skills are only available to experts. Sketching-in-Light is a novel toolkit to assist with designing and evaluating the characteristics of low resolution lighting displays as well as content variations using different materials. The components of the toolkit include a tablet, a custom-built app and low-cost prototyping materials. The toolkit can easily be replicated and adopted by others working in this domain to prototype lowresolution lighting displays without requiring any previous expertise in hardware prototyping.