Participatory sensing has the potential to support human-driven sensing and data collection at an unprecedented scale. In this emerging class of software systems, participants use an application on their mobile phone to collect digital samples of the surrounding world using on-board sensors (e.g., camera, GPS, accelerometer). Such an approach can supplement data from special-purpose sensors, or even replace their use, providing data from a fine-grained, human perspective and potentially reducing the costs of large-scale data collection efforts.While many potential participatory sensing campaign organizers have extensive domain knowledge that drives the need for large-scale data collection and analysis, they do not necessarily have the skills required to develop robust software for participatory sensing. To address this challenge, I present Mobile Campaign Designer, a toolkit which lowers the barrier for the development of participatory sensing applications. Using Mobile Campaign Designer, a campaign organizer can provide a simple, descriptive specification of the requirements of their participatory sensing campaign, and the toolkit generates the source code and an executable for a tailored mobile application that embodies the current best practices in participatory sensing. Since participatory sensing applications typically are used to study physical phenomena, the toolkit includes an algorithm that considers spatiotemporal requirements for the crowdsourced data set and recruits volunteers that can help to satisfy those requirements.Furthermore, this work lowers the barrier for the creation of participatory sensing applications for a diverse group through the Mobile Application Development for Science program, an outreach and educational initiative aimed at engaging middle school students with science and technology and increasing their interest in careers in science and technology. Using the Mobile Campaign Designer toolkit, along with other mobile application development tools, students will design and conduct a participatory sensing data collection campaign. The students define their campaign, create their mobile application, collect samples, and analyze the results of their data. In addition to lowering the barrier for participatory sensing application development, the program is intended to serve as an intervention that will impact attitudes and perceptions towards science and computing, thus broadening participation of underrepresented groups in science and technology.