New productions and prototyping can only be successful if you constantly test your materials, design and productions using appropriate tools and depending on your objectives.
Learn here how to quickly test you productions with a battery and a led but also more interestingly how to test them with a multimeter and how to use microcontroller to acquire related signals.
When building resistors wand small circuit components with Papier Logik resources, a power source and a led may be enough to test shortcut and relative voltage outputs when resistance values are not too high (below the kOhms order).
This can already lead to a lot of fun and educational applications with little resources but when developing higher levels components such as more complex circuits or sensors, an Ohmmeter or equivalent digital tools should become you friends sooner or later. Here is a collection of good practices and useful information related to securely buildng, testing and specifying you sensors.
Testing with an Ohmmeter
A multimeter is the best tool for detecting shortcuts and measuring conductive materials and resistive sensors. Set as an ohmmeter,
Be aware that you will not read the same value for a component if you test it on the side or if you test it inside a powered circuit.
Testing with an Arduino
An Arduino is the best way to test and use resistive-based sensors, but also to build low-cost oscilloscopes to test materials and used them to build components.
With sufficient output range (e.g. 1k to 100kOms) a Voltage divider makes a simple electronic circuit to plug a resisitve-based sensors. but other techniques can also be of interest.
Then a development with a micro-controller that can be plugged to a computer or another peripheral like an arduino is a great start for building you first Human Interface Device with a variety of applications and efficiency.