Custom Piezoelectric Keypads for Rugged Environments
What is piezo keypad technology?
Piezo keypads use an ingenious phenomenon… the release of voltage through pressure. In simple terms, the piezo effect occurs when certain materials (crystals, some ceramics, etc.) emit a voltage when mechanically pressed. The voltage emitted is proportional to the change in force applied. Conversely, when a voltage is applied to a piezo material, the material will “move” from a static state.
What is Dynapic?
Dynapic (pronounced “die-nuh-pik”) is the brand name for piezo keypads manufactured by Pannam Imaging. The piezo elements used in Dynapic piezo keypads are so sensitive, they can detect actuation (key press) through very thick graphic overlays, such as Metalphoto anodized aluminum, etched stainless steel, thick acrylic, and glass.
The ability to use thick, rigid graphic overlay materials makes Dynapic piezo keypad technology an extremely robust and durable keypad solution for harsh, rugged, and abusive environments.
Dynapic piezo keypad assemblies are especially vandal-resistant and robust, as well as resistant to temperature, chemicals, and moisture, making them an ideal solution in applications such as:
- Oil & gas equipment
- Self-service kiosks and Point-of-Sale kiosks
- Food processing plant machinery
- Chemical and laboratory instruments
- Bank cash machines/dispensers
- Weighing & cash machines
- Railway equipment
- Vending machines
What are the Advantages of Dynapic Piezo Keypad Assemblies?
- Rated to exceed 10 million actuations
- Virtually no mechanical wear and tear
- Unsurpassed vandal-resistance and durability vs. traditional membrane switches
- Chemical, temperature, moisture, and vandal-resistant
- Outdoor weatherable
- Unaffected by changes in air pressure
- Adjustable operating force
- Heavy-duty overlay materials can be used: Metalphoto anodized aluminum, stainless steel, acrylic, glass, etc.
Dynapic Operating information
- Dynapic keypads are non-tactile with no moving parts. Wear and tear is substantially reduced.
- An active voltage pulse (proportional to the change in force) is emitted when pressure is applied to the graphic overlay keypad.
- Simple interface circuitry is required to convert the piezo signal from analog to digital.
- Interface circuitry can be custom-designed, or you can use Pannam’s own custom ASIC interface controller which has the following features and functions:
- These CMOS signals are available as serial, parallel and as a matrix for further processing.
- Amplifies and digitalizes the piezoelectric signals produced by the keypad.
- The switch sensitivity is set electronically through the adjustment of the switch point on the ASIC.
- The ASIC can “latch” the pulse signal and emulate a “continuous press” signal, or closed circuit.
- Eliminates contact bounce typically associated with other switching technologies.
What are Some Design Options for Dynapic Keypads?
- Graphic Overlay Flexibility – robust, durable, rigid overlay materials can be used. An excellent option for outdoor use and resistance to temperature and harsh chemicals is Metalphoto anodized aluminum. Center-to-center key spacing can be affected as the overlay materials get thicker. Graphic Overlay material choices are:
- Aluminum: .020” – .187” thick, .020” standard
- Polycarbonate/Acrylic: .007” – .118” thick, .030” standard
- Stainless Steel: .018” – .032” thick, .018” standard
- Glass: .020” – .060” thick, .060” standard
- Adjustable Actuation Force: Varying the actuation force can be accomplished through adjustments in the interface electronics (circuitry).
- Visual and Audible Feedback can be utilized to enhance feedback to the operator.
- Rigid Support Panels: Structural support is provided by utilizing aluminum, stainless steel, or thick acrylic subpanels. Mounting hardware (PEM studs and standoffs) can also be incorporated.
- ESD, EMI & RFI Shielding
- Clear or tinted display windows & lenses can be utilized
How Dynapic® Technology Solves Your Membrane Switch Problems
|Problem||Traditional Membrane Switch Technology||The Dynapic® Solution|
|Switch failure due to piercing, denting, or scratching the graphic overlay.||Graphic overlay thickness is limited to .007 – .010″ polyester or polycarbonate, which is easily pierced.||Graphic overlay can be anodized aluminum, stainless steel, thick polycarbonate or acrylic.|
|Switch failure due to tactile feedback stress on material.||Many switches are designed with tactile feedback, which can accelerate switch failure.||Eliminates tactile feedback to maximize switch life.|
|Switch failure due to constant material stress/flex and movement.||Can only work by moving materials through a spacer cavity, causing material stress.||No moving parts.|
|Silver migration, trace oxidation & air pressure equalization problems caused by air vents.||Air vents are required for proper switch function. Creates opportunity for contamination, oxidation, silver migration, & switch collapse (from pressure equalization).||Eliminates air vents.|
|Input speed for high volume data applications.||Slow input speed||Fast input speed. Actuation pressure is controlled by electronics.|
- Voltage: typically 1 V/N (burden 10 MOhm)
- Time constant width: typically 70 ms (burden 10 MOhm)
- Capacitance: 5-20 nF, typically 7 nF
- To download the Pannam ASIC Technical Specifications, click here.
- Typical aluminum overlay thickness: .020″
- Mechanical loading: up to 200 N/cm2
- Operating force: from 0.1 to 100 N
- Required operation speed: approx. 10 N/s
- Maximum cycles per second: > 1000 Hz
- Storage temperature: -60 °C to +80 °C
- Operating temperature: -40 °C to +60 °C
- Number of press cycles: > 10 million
Set your equipment apart from the competition.
Our process is simple…
- You receive the most benefit when you consult with us early in your project. Pannam’s U.S.-based design engineers work closely with you, offering expert recommendations and support to create a dependable rubber keypad design that is built in our ISO-certified facility to meet your application requirements.
- We recommend the most practical and cost-effective solution that meets your requirements and satisfies your goals.
- You have a direct line of communication with our design engineers to stay informed about the progress of your project.
- Advanced printing and fabrication capabilities, and trusted suppliers enable us to select the best components for your integrated assembly.
- The final delivery is a robust, feature-rich, piezo keypad assembly that will set your equipment apart from the competition.
Contact Pannam now to discuss using a Dynapic keypad assembly in your product design.
Visit our Product Gallery to learn more about the various constructions and product features we can offer, and how Pannam can customize your membrane switch design to meet your unique application requirements.