The DropBot system is described in detail in "Fobel et al., Appl. Phys. Lett. 102, 193513 (2013); doi: 10.1063/1.4807118". If you use this information in work that you publish, please cite as appropriate.

DropBot updates and EMC testing

We’ve been silent on the blog for the past few months, but fear not, DropBot development has not stalled. In fact, we’re going full steam ahead and getting ready to release the next (v3) DropBot system. There are a lot of updates (too many for a single blog post!) so I’ll stick to some highlights to get people caught up.

The Measles/Rubella field trial that happened last spring in Kenya was a resounding success ([1], [2]). Here’s a video documenting the project:

The journal publication should be coming out very soon and we’re currently gearing up for the next iteration, a follow-up study scheduled to take place in August/September in the Democratic Republic of the Congo.

There have also been some exciting new developments in the Wheeler Lab involving new methods for printing DMF chips. For those interested in chip fabrication, I would highly recommend checking out this paper.

Finally, we’ve spun out a new company Sci-Bots Inc. that will make it easier for people to get their hands on a DropBot and start using DMF to solve important problems in biology and chemistry. We will provide more information soon in a future post, but here’s a sneak preview of a pre-production system.

DropBot v3-pre

What is EMC?

This remainder of this post is going to focus on EMC testing, which is something we’ve been thinking about a lot in our efforts (through Sci-Bots Inc.) to sell DropBots to people around the world. EMC stands for electromagnetic compatibility. EMC regulations apply broadly to anything containing electronics and are designed to ensure that any new electronic gizmo is not going to cause interference with other equipment (emissions standards) or be affected by RF noise, electrostatic discharges, etc. (immunity standards).

If you’re just posting designs online for people to build themselves, you probably don’t need to worry about such things; but if you want to actually sell a product, adhering to at least the emissions standards is mandatory in most jurisdictions (e.g., FCC in the US, Industry Canada). Selling to the European market requires compliance with both emission and immunity standards (along with several other additional requirements) to attach a CE mark.

Testing is expensive and takes a lot of time

Even in the simplest cases, emission testing can cost several thousand dollars (sometimes over ten thousand dollars for immunity testing). Selling non-compliant electronics could subject you to significant fines and it may be difficult to ship things across borders without documentation of compliance. This creates a significant barrier to small-scale production of hardware, especially when you consider that any non-trivial change/revision you make to your product requires a retest.

There’s also the issue of safety standards (e.g., UL, CSA, TUV, etc.). These are not required to legally sell a product, but they may be demanded by some customers (e.g., US government labs). Conformance with these standards requires some hefty fees and on-going testing (factory inspections, etc.). We have not pursued safety certification for DropBot yet (it is even more expensive than EMC), but we do take safety very seriously and are trying to make the new DropBot as safe as possible. For future versions, we will consider pursuing formal safety certification, since we expect it to become increasingly important as DMF matures and people want to start using DropBots in schools, hackerspaces, and in their homes.

How to meet EMC standards?

In a future post, we will go over some of the changes we made to DropBot v3 to address the EMC regulations. We haven’t yet finished all of the EMC testing, but we performed an emissions pre-scan earlier this week and it looks like the new DropBot v3 comfortably falls within class A limits (suitable for commercial/industrial customers). We are close to meeting the Class B requirements (home use) and have pretty good idea how to meet that stricter standard too (hint: USB cables are a major source of emissions).

EMC pre-scan results


I will close this post with some links to technical resources that we found useful in designing electronics for EMC compliance. EMC FastPass offers a free EMC design book (note that you need to register your email to download it) and also hosts a number of interesting articles/blog posts on the subject. The test lab we are currently working with here in Toronto, Canada (Ultratech) also has a very nice pdf/design guide that covers many common issues and solutions.

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