digidrench. Great use of our eTape liquid level sensors!
digidrench is an interactive video installation in which the user controls video playback by filling and draining three tanks. As the water level rises, the video plays forward; as it lowers, the video reverses. The user gets to interact with the very same materials that are used on screen. As the user pours, liquid falls on screen. There is a direct correlation between the user’s action and the video content, allowing for more playful and meaningful engagement with the project.
Our assignment was to develop a media controller. Early in our brainstorms, we chose water as the project’s theme and instrument of control. After hours of discussion, we settled on using fluid levels to control the video playback. The user can manipulate both the speed and direction of playback. The faster you pour the water into the tank, the faster the video plays. Draining the tank reverses the footage. The tank’s design mirrors the aspect ratio of the video screen. The inspiration for the video clips came from researching slow motion video of fluid.
The digidrench tanks are made from sheets of acrylic, which were bent and affixed with PVC cement. Some pieces were cut manually with a band saw and others were laser cut. Plastic water cooler spigots allow the tanks to drain.
Inside the tanks, fluid level sensors relay water levels to an Arduino, which in turn passes those values along to a computer running Maxwith Jitter. Max uses the data from the Arduino to “scrub” the video playheads back and forth.
8″ eTape Liquid Level Sensor + extras. The eTape Liquid Level Sensor is a solid-state sensor with a resistive output that varies with the level of the fluid. It does away with clunky mechanical floats, and easily interfaces with electronic control systems. The eTape sensor’s envelope is compressed by the hydrostatic pressure of the fluid in which it is immersed. This results in a change in resistance that corresponds to the distance from the top of the sensor to the surface of the fluid. The sensor’s resistive output is inversely proportional to the height of the liquid: the lower the liquid level, the higher the output resistance; the higher the liquid level, the lower the output resistance.
This is a very unique sensor, we haven’t seen anything else that is affordable and accurate for measuring liquid level. This sensor seems like it would be a handy addition to an hydroponics, aquarium, fountain or pool controller, or perhaps measuring a rain tube. This particular sensor is the 8″ model, we also include a 3-pin connector and 470 ohm resistor. The connector is so you don’t have to solder directly to the delicate pins: instead, just solder to the connector and plug it onto the sensor.
Since the sensor is resistive, it is easy to read it using a microcontroller/Arduino ADC pin. Check the tutorials tab for a quick-start pointer.
- Sensor Length: 10.65″ (297 mm)
- Width: 1.0″ (25.4mm)
- Thickness: 0.015″ (0.208 mm)
- Resistance Gradient: 55Ω / inch (22Ω / cm), ± 15%
- Active Sensor Length: 12.6″ (320.7 mm)
- Substrate: Polyethylene Terephthalate (PET)
- Sensor Output: 700Ω empty, 85Ω full, ± 15%
- Actuation Depth: Nominal 1 inch (25.4 mm)
- Resolution: 1/32 inch (0.794 mm)
- Temperature Range: 15°F – 140°F (-9°C – 60°C)
