A multimodal feedback is not only more distinct and easier to process, but it can also shape the characteristics of the haptics further.
→ Receiving a notification on your phone in a muted vs. unmuted state
Depending on the material and build, the feedback will spread across the whole object. Isolate the actuated surface if necessary.
→ In small devices with tight fitted parts, the position of the actuator might not matter
Place the actuator as close to the physical user input as possible, but keep in mind the required assembly space including trigger electronics.
→ Not every application allows the interaction of active haptics
Haptic perception is not equally distributed and perceived across the human body.
→ Higher frequencies can work great on the fingertips, but are highly uncomfortable when used on the head
Different types of actuators produce varying haptic sensations which might or might not be useful in your case.
→ LRA’s are a great start, but very limited in their character bandwidth
The driving electronics can have a big impact on the feedback.
→ ERM’s or LRA’s work best in close-loop systems, while voice coil actuators also work well with audio signals
Define the context, functionality, characteristics and content of the feedback before your start modulating.
→ Different paths are required to achieve a crisp confirmation or a pocking warning
Environmental influences such as mechanical noise and temperature can impair the haptic perception.
→ Hands and feet are sensitive to picking up environmental influences (Power drills, chainsaws..)
By replicating common characteristics, the feedback becomes less artificial and easier to recognise.
→ Emulate characteristics and patterns from similar mechanics or human interactions
All modalities should communicate the feedback coherently (characteristic/ intensity,..) and perfectly timed.
→ With simulated button clicks, we can sense a wrong timing down to microseconds
Our body can perceive a broad bandwidth of characteristics, but has trouble identifying only slight differences.
→ Make use of a high contrast in the parameter values for different cues
Haptic feedback is most powerful when you can intuitively react on it.
→ The more complex the feedback, the less immersive it becomes and more repetitions are needed to learn it
Design the haptic intensity level with care or let the user decide.
→ While we can close our eyes, we can not turn off our haptic perception
Create tangible prototypes throughout the process to validate changes.
→ Even small alterations in the signal can have a big impact on the characteristics and perception
The material and construction of an object directly influences the perception and spread of haptic feedback.
→ Different materials and connections such as using glue vs. screws will have an impact
The perception is highly influenced by the context and the users behaviour.
→ Evaluate it in the final context considering eg. proper clothing, equipment and other possible distractions
