A recent project that MKC completed in record time integrated an mp3 decoder within a membrane keyboard front panel to provide a high quality switchable stereo output locally decoded from audio files stored on an sd card.
Interactive exhibits/Museums/Visitor Centres
Adding Audio interaction for user interfaces
Pre defined warning messages
Audio demonstration equipment
If your project has limited visual I/O or processing, this solution can enable high quality audio to be generated from easily accessed . Mp3 files stored on an SD card. The DSP hardware processing the c ompressed audio files in real time, while freeing the control processor for other tasks. As files are stored on a standard SD card, generating/editing/updating (for instance for other language variants) is a straightforward task. Development is speeded up using this proven hardware which has been through CE certification. manufactured in groups of 4.
The PCB measures 80x42mm and can be rear mounted to a custom front panel membrane keyboard PCB (type up to 9 keys and up to 5 LED indicators).
Prototype component sourcing & construction
Prototype testing/code development/modification
Customer approval of prototype
PCB/Mechanical design & Layout
Production PCB manufacture & testing
Updates for manufacture
Final PCB hardware sample manufacture
MKC started to source components at the initial hardware design stage to ensure that no long lead time components were being designed in. By coordinating the manufacturing phase whilst product development was underway we were able to deliver productio hardware at the 12 week deadline.
Our solution uses a high-performance, low-power DSP based system capable of reading and decoding the .MP3 input dat astream at high bitrates. Using an 18-bit over sampling, multi-bit, sigmadelta digital to analog convertor at the output stage ensures a high quality stereo audio output with no phase error between L/R channels.
Software controlled volume levels for L & R outputs is supported if needed.
An Atmel AVR single chip processor takes care of the user keypad inputs, LED indicators on the front panel, control of the decoder and output audio signal routing to one of 2 stereo outputs.
Source files are encoded in Mp3 format (up to 320k bit rate), Also supported: WMA, AAC, AAC+, Ogg Vorbis, FLAC and MIDI A Standard size SD card socket fitted on the PCB, supporting FAT16* (*NTSC file format not supported).
2x Stereo 3.5mm jack sockets for A + B audio output
2,1mm power jack for 5v power
Header for ISP and serial downloading of code (processor & DSP)
Power requirement – 5v D.C (An on board regulator provides the 4 different voltage rails required and a voltage monitor ensures that the unit will always reset reliably after a power rail interruption).
Information provided as an example only, most solutions are custom designed for your application so please get in touch for more in depth technical information or a quotation for a particular project.
PCB Based Membrane Keyboard
MKC were approached by one of the UKs leading marine searchlight manufacturers to produce their next generation interface.
The assembly would be fitted within commercial and naval bridge consoles and through close collaboration at the design stage MKC were able to offer practical solutions to key customer requirements.
The project required full concept, development and prototyping prior to MKC being awarded the contract for volume manufacture.
Backlighting for key location in a darkened bridge environment
Customised RGB LED light tile set with light emission controlled by the customers hardware. Designed to fit around board furniture and mechanical components in order to best use the available land on the PCB. Further enhancements to the light effect were achieved by adding selected tinting and secret-til-lit prints to the graphic overlay.
Variable temperature and UV Resistance
MKC recommended Autotype XE to manufacture the graphic overlay. Autotype XE is a polyester substrate with embedded chemical additives which provide resistance in hostile environments.
This offers a longer life expectancy for the product and reduces the likelihood of failure in the field.
Ruggedised for operator and environment
PCB based membrane keyboard acting as both a backplate and providing land for electronic & mechanical components. Rim embossed key locations fitted with 350gram operational force tactile domes allow for location with finger and positive response once actuated.
MKC were approached to produce a screen printed graphic overlay which would be fitted to a hand held nurse call unit for a leading healthcare manufacturer.
Working from customer supplied technical drawings we were able to provide additional technical expertise when recommending the correct adhesive systems for applying the graphic overlay to an ABS enclosure and providing flexible supply options in order to meet the customers target costings.
Owing to the environment the graphic overlay would be located in, assisting in the resistance to hospital borne infections and bacteria was critical as the nurse call unit would be operated by both staff and patients. MKC recommended an anti-microbial front face screen print which satisfied this key requirement whilst maintaining the aesthetic qualities of the fascia.
MKC recommended contrasting colour arrangements with simple command instructions and incorporated pillow embossed switch positions for operator location.
Manufactured in volume and held in stock to give the customer favourable pricing and continuous supply for unexpected demand.