alt.embedded

Building Surface Mount Prototypes

I recently spoke with Screaming Circuits and Sunstone Circuits at the recent Embedded Systems Conference (ESC) (watch Sunstone Circuits PCB Design Services). After this discussion they gave me a small box full of parts, circuit board and a flash drive with the design materials. They also covered one free project, this one, using their online order service. Screaming Circuits targets prototypes and small run projects.

It was an interesting exercise. Of course, everything was provide but that is about where one would start for a custom project as well. I was able to run through the order process from my hotel room in San Jose after a day of interviews at ESC. Screaming Circuits interface was on par with PCB online ordering services I have used in the past. I have not used Sunstone's yet but I have walked most of the way through their order process. The trick is getting all the materials into the system. Unlike most PCB ordering, assembly requires significantly more details. All the components need to be identified. Of course, having the right development tools makes things handy.

Once completed, the order process provides a project number to include with the parts being sent in. I sealed up the box and dropped it in the mail. The left over parts and the finished board (see figure) arrived a little later.

The project was relatively simple but it utilized a good bit of surface mount technology (SMT). This is on par with most projects these days. I have hand soldered a few SMT chips and components but it is not easy. It is definitely harder than dealing with parts in the past and I have worked with most technologies including wirewrap.

The test board holds a Microchip PIC. It was designed with an ICSP debug port so reprogramming is an option. The program drives the 18 LEDs along one side. The board runs off a pair of batteries mounted in a holder underneath.

The pricing is reasonable but it pays to do more than one board at a time. The estimated price for this project was about $400 and I supplied the parts and circuit board (well, it was given to me but you get the idea). That is steep for a single board but most of that is for setup costs. The construction was actually challenging because it had the battery holder on one side, through hole components as well as SMT components. The price per board drops significantly as the number increases.

Even starting with only a couple boards makes sense if more are needed later. This lets you test the new boards before going with quantities. Set up charges or change costs are more readily amortized over the long run.

Like the competition, Screaming Circuits provides a range of services. Online quotes are available for short run, simple prototypes and full prototypes. Parts procurment is an option in case you don't want to supply them yourself. They can even develop an entire kit so products are ready to ship.

Turn around time is based on pricing. The cheapest run 5 to 10 days for prototypes, longer for short runs. One or two day turn around is available at a premium.

If I ever needed to do another project with SMT parts then this is definitely the way I would go. The results speak for themselves. I guess I'll give the board some exercise with Microchip's new MPLAB X IDE (see NetBeans Powers New PIC IDE). But that is another story.

TAGS: Dev Tools
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