The Sprout Board
Recently we designed and produced a very interesting product called the “Sprout Board”. This kit based circuit board project is designed to help the arduino platform take a step towards more practical final product based projects. This circuit board acts as more of a motherboard than a shield and allows you to connect one shield in addition to the arduino onboard. The design breaks out the existing IO on the arduino and makes it accessible through terminals. Some of the more common devices are also found on board like a serial header to connect an LCD as well as a speaker and CDS.
While I could talk all day about this project and our goals with it, I felt that it would be a good idea to just briefly discuss the design process we went through with some examples so we could share our experience. If you would a more in-depth look at the sprout board you can check out our site for the product at SproutBoard.com.
Step one of course is to bread board your project and make sure it works. But once you have a working circuit then what do you do? We began by picking up some perf board and experimenting with component position. After 3 or 4 mockups we found one that we liked for several reasons. This design is very flexible and can be put in several chassis designs. In addition to flexibility it also utilizes components that are easy to access for the user. Finally as we were intending to offer this as a kit we made a conscious decision to use only hole through components and no surface mount items to keep this as accessible to our customer base as possible.
The next step was to jump into eagle cad and make the project happen. While learning about fab shops and there offerings and software we came to a very early decision that we wanted to use something like Eagle cad for our board so we were not locked into a proprietary format for a single vendor. Also often the vendors that offered a software solution we found were the most expensive! This also is a great time to order your bulk components. We used Newark because there prices were the best!
Once we were satisfied with our board design we sent out a large order with a reputable company out of the Philippines. Because of distance and priority we had a good 2 week gap in the process. During this time we were able to use our mockup boards to produce the chassis designs. For our chassis designs we used Coral Draw and exported to DXF format for use with Ponoko. This on demand fab shop cuts all of our chassis. This allows us to control costs and provide a very nice product to our customers.
Finally everything started to come together. Our sample boards arrived just before our chassis from Ponoko and we started soldering. Beyond just assembling to see if it would work, it is also important to make sure that it is easy to put together. This is kind of the last chance before you pull the trigger and pay a lot of money for a large order. Make sure the kit is user friendly.
With all the goodies on hand now we start testing. We want to make sure that the setup is stable and rock solid. We put our testing platform through some rather punishing tests in freezing cold and blistering sun to make sure that it was stable.
With the last of the components coming in we get the finally assembled project. Sadly we designed the board to use a mic that was offered from spark fun that was discontinued the same week we launched the project. Well… now we get to design and sell our own version in its place, but be careful about using open source designs from vendors… things change a lot.
Finally we install and use the hardware we designed. I really love the design process and I hope this little glimpse into the design process for the sprout board has been entertaining.
You can buy a sproutboard here: Link