Embedded Hardware Design and Development is an integral part of product development. These services are intended to complement the embedded systems design and software design and development services offered. This hardware design is for microcontrollers and microprocessors or smaller FPGA systems. The hardware design, both mechanical and electronics, is done in parallel with software development..
Embedded System Hardware Design and Development Overview
The hardware design process involves both mechanical design and electronics design. The basic process starts with conceptual design during the embedded systems design and requirements specification phase. In this activity the requirements and conceptual design is explored further to ensure suitability for the final implementation. The following factors need to be considered to ensure that all elements of the design will come together later. These elements are detailed in the embedded economics - managers section of the web site.
- ● Bill of materials (BOM) costs
- ● Manufacturing cost
- ● Usability
- ● Durability
- ● Power consumption and battery life if applicable
- ● Fit and finish
- ● Product image
- ● Design for manufacture
- ● Repair costs for expensive devices
- ● Display visibility
- ● Heat disapation
- ● Noise
- ● Acoustic quality and properties
- ● Weight
- ● Electronics size and configuration with packaging design
Hardware Design Process
The hardware design process is as follows:
- ● Node Hardware Requirements specirfication
- ● Detailed node architecture and design for electronics in parallel with detailed mechanical design and packaging concept and initial prototypes
- ● Part selection, schematic capture, printed circuit board design and layout in parallel with mechanical prototype refinement
- ● Prototype assembly and further mechanical refinement
- ● Prototype bring-up, design verification and testing
- ● Documentation and support in parallel with automated manufacturing testing and end of line testing.
The mechanical design of the system should be based on experience of the mechanical, electronic and packaging design team. This experienced team is critical as many factors can affect the design. RoweBots has a team that has solved problems like this for many years and has extensive consumer product experience. This experience is critical to a high quality final design.
The next critical element in the mechanical design portion of the embedded hardware design and development is to converge on a single design that meets all of the overall criteria. By converging on a single approach, the effort of perfecting the design can be focused on a single design. If there is risk issues associated with the design, these risk items should be resolved early through research and experimentation.
An example of risk reduction might involve a prototype of the case made with a 3D printer, which might then be stuffed with a dummy circuit board wih an attached speaker and wires which are put through a hole in the case. The unit could then be closed and the speaker driven by an external source to test the acoustic properties. This would just reduce the risk because the final case would be different, but it could provide a good measure of resonance problems and other related issues.
The electrical and electronics portion of the design must occur in parallel. Both proceed to completion in parallel. Issues in either the electrical or physical design can force rework in the other. This is why it is necessary to eliminate risks early as it will minimize the overall cost.
From the specifications, the electronics design is undertaken using developers which are as experienced as the project is difficult. Often for simple single board microcontroller designs, more junior designers are used with an experienced supervisor. In the case of more complex designs with multiple add on boards, a better more experienced designer is required. Generally though, microcontroller based designs and small microprocessor designs or simpler FPGA designs do not require the best and most experienced designers.
As in the mechanical design case, risk reduction at early stages is a priority. An example of risk reduction could involve a trial hardware layout of the components on the circuit board to make sure that they will all fit. The goal might be to make a 4 layer board, maximum to keep within the BOM cost range. The trial layout would determine the physical layout, confirm that the heat could be disapated and all the components could fit comfortably using the preferred packaging approach (ie SMT, BGA, ...) and that the other constraints were met.
The designers will have periodic meetings to ensure that the two halves of the design are working together well. Often with plastic cases, the main concern is getting the connectors exactly aligned with the case and the case's closing mechanism working well. With metal cases, issues of shorts between the board and the case can be problematic particularly given that the size of the box generally needs to be a minimum size.
At then end of the integration process, and after the testing process, a gold unit is achieved. It is this gold unit along with schematics, gerbers, and CAD drawings (complete with final tiny modifications) which are passed to manufacturing.
As part of the embedded software design and development, and as part of the embedded hardware design and development, an automated manufacturing load and test system is created. In the project plan components of both hardware and software are required. It is even possible that the parts are delivered to the manufacturer preloaded with firmware. During manfacturing two tests are still required:
- A test is required to ensure that the electronics which are assembled into the final device all pass tests to ensure they are working exactly as the golden unit. This test should be totally automated if possible to eliminate any costly handling and potential static problems at this phase.
- A second end of line test is required where the final unit is powered on and tested to ensure that nothing went wrong between the electronics test and the final assembly. Often this end of line test involves loading the final software. Again this test should be totally automated to eliminate costly handling.
During this embedded hardware design and development process, problems and issues can forced a regression to a previous step to correct the problems. It may involve software design and implementation work as well; however, in this case, a common refrain is: "well just fix it in software". Be aware that this is often not the best answer for maintenance purposes as "hacks" are added into the software which don't match the original design.
The hardware design process can be split many ways. Since it affects the physical device delivered to the end user, it is best to have client marketing involved to approve the overall and then final approach. The actual work can be split between client resources and RoweBots resources with the management approach chosen depending on the availability and skill level of the managers.
|Client needs||Model of operation|
|Clear and static specifications||Delegate project to RoweBots|
|Tight control with adequate supervision resources||Client direct supervision model|
|Few supervisory resources and/or minimal project knowledge||RoweBots team leader solution|
All hardware design and development arrangements are determined on a custom basis, please contact us to get a quote.
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