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Tablet-linked instruments

Tablets are an effective way to bring a touch-screen interface, computational power, and wireless connectivity to a range of scientific instruments. Typically, the above elements must be integrated separately into each instrument, adding significantly to the complexity and cost of the device. If we use the tablet as a common platform to host diverse instruments, we can simplify the remainder to the point where it can be constructed cheaply as a DIY kit. 

We are designing open-source DIY scientific instrumentation accessible to classrooms from both a cost and technical understanding perspective. In terms of cost, the instrumentation can be assembled cheaply using tools such as 3D printers and laser cutters, in combination with modular components such as Arduino microcontrollers. In terms of technical understanding, the instruments are built in a simple and modular fashion, with complete documentation and few “black boxes.”

As a bonus, because the designs can be modified and extended, they also offer a way to incorporate engineering and programming into lessons, allowing students to gain further familiarity with physical principles underlying the operation of their devices. Simplifying technology to the point that it becomes intimately accessible to students and teachers is expected to provide more time for inquiry-driven science.

Open-source DIY instrumentation, wirelessly linked to iPad for data collection. Shown below is a pH probe; we can also attach probes for measuring dissolved oxygen, conductivity, oxidative reductive potential, etc. We will be introducing these devices to high school students as well as Caltech undergraduates in Ch 3. 

The probes are from Atlas Scientific (, the microcontroller is an Arduino UNO R3 with a Bluetooth Low Energy shield, and the iOS application, which supports logging and e-mailing of data from all probes, was custom developed by CSA@Caltech.


An assortment of inexpensive sensors ($2-20, below) to measure pressure, temperature, particulates, oxygen, natural gas, alcohol vapor, humidity, etc. can be wirelessly linked to the iPad as well. Sensors are available from companies such as SEEED studios ( and DF Robot ( We are building a circuit board that supports simple prototyping of circuits for environmental monitoring applications. 


Tablet interfaces to existing IO Rodeo instruments. We are collborating with IO Rodeo (, a local company dedicated to making DIY open-source scientific instrumentation available and accessible to all. They have developed a colorimeter kit ($85) as a tool for education, useful for research studies involving the distribution of organic and inorganic compounds in the environment. We are working with IO Rodeo to make their colorimeter wirelessly linkable to mobile devices via Bluetooth, so that it can be used as a portable field device.