When working with embedded systems, especially in the early stages of development, there are often one-off development test fixtures that need to be created to help support the development process. These can range from custom cable harnesses to special power supplies, adapters for development dongles and more depending on the project. More often than not, this equipment is built manually on an ad-hoc basis, which can be time consuming to create.
These tend to grow as project requirements change, unfortunately resulting in cumbersome cable looms which are time consuming to recreate. Because of their ad-hoc nature, they tend to be fragile and often difficult to work with.
First generation cable loom for an internal project
These fixtures also tend to be shared widely - they're given to new team members , they get allocated to long-term testing, provided to third parties for manufacture testing and so forth. Because they are valuable and more widely used than originally anticipated, more need to be created. Creation of new pieces often falls to the original designer, pulling them away from important development work and is rarely the best use of their time. This practice tends to stem from the core idea that on-site engineers' time is ‘free’, and that engaging in external manufacturing is expensive, time consuming and limited to high MoQs.
However we have found that this has not been the case in recent years, as small-scale manufacturing has become more prevalent, easily accessible and the process of designing and ordering PCBs has been simplified and streamlined considerably. This in turn has led to the manufacturing of development test fixtures in small quantities being more accessible, and not nearly as expensive or time consuming to set up as people tend to think.
Using modern prototype manufacturers it is possible to have a simple PCB manufactured and assembled in less than a week, for a cost of around $20USD/board in runs of 5-10. Some manufacturers even provide simple online PCB design and layout tools, so that traditional third party software isn’t a necessity, again reducing the entry barrier to small scale manufacturing.
Having these kinds of boards readily available to developers streamlines development tasks that would previously have been difficult or time consuming to set up - such as having long-running tests active. As fully manufactured and assembled PCBs, they are also significantly less fragile than their handmade counterparts making packing up test equipment to use at a new site, as well as travelling to customers or remote offices easier with a more robust development setup.
Replacement PCB of the first generation cable loom above
While the cost moves from an engineer’s time in piecemeal assembling of development fixtures to PCB design and small scale manufacturing setup, the relatively small upfront effort to create a PCB results in significantly more effective use of their time later on in the development process.
Whereas previously creating the equipment would have scaled linearly with an engineer’s time, using a small scale manufacturing service makes it significantly easier to create more pieces of equipment at a fraction of the cost. Where it might take an engineer a few hours to make a one-off piece of equipment, you could instead - for a fraction of the price once you take their time into account - order 30 pieces and never have to worry about it again.
Using a manufactured PCB instead of an ad-hoc manually created piece of equipment in this way also means that your design is now properly documented and easily reproducible. Most prototype manufacturers make subsequent orders very easy, so obtaining new boards is really as simple as an online credit card purchase.