Security in electronics is tricky. Everyone can think of grounding or protection for high-current devices, but even when designing small devices, details need to be addressed.
What is the risk with electronics? Electric shock, fire from overheating or short-circuiting, or possible damage to connected components due to overvoltage or improper design. Often we also have to consider the mechanical risks of moving parts. Functional safety is also addressed in electronics design, either designing when a device “must not fail” (medical devices) or it can fail but only in a safe way (e.g. a train brakes).
Many of the safety flaws are not immediately apparent, but have the character of a hidden time bomb: the device is fully functional, mass-producible, but has the lurking pitfall of a risk of shock or fire.
Let the electronics design be assessed by experts
The design software can alert you to some design errors. We use Altium Designer, which is top-notch, but there are a number of other, more affordable tools that may be enough to get you started.
Unfortunately, even the best software may not detect everything – in the basic setup, it is only able to indicate unconnected connections at most, so it is a good idea to contact professionals with practical experience to check. They can assess not only whether the design is right, but also what situations may arise in practice when using the product for a long time and whether there is a safety risk or reliability problem somewhere.
If you come to us with a design or prototype, we will be happy to advise you and we will also arrange all the necessary testing.
We want to save you from a situation that we have experienced ourselves.
We discovered a security flaw in a youth kit
Our company has been helping to organize electronics competitions for children and young people for more than 15 years. The contestants, who are anything between 10 and 18 years old, show their DIY devices and we always advise them on what and how to modify them to make them safe. They are very skilled and competent, so we usually don’t see major problems and almost half of the devices are faultless and would pass safety certifications without much trouble.
This year, however, one of the participants brought a home-made twilight switch for 230 V / 10 A lamps, created using a DIY kit from one of the Czech manufacturers of these kits. When we saw the schematic, it was clear to us that there was a really big safety issue.
There are two circuits on the board – 230 V (thick connections) and a 12 V SELV control circuit (other connections) which should be safe to touch. However, the isolation distance between them is essentially non-existent.
Standards (e.g. EN 60335-1) typically require a distance of 3.5 – 8 mm. In a clean environment and with new hardware, even less than 1 mm will be practically sufficient: the device will work and we will not get a shock from it. Why is the distance in the standard so much higher? For long-term reliability and design margin: not for nothing do the standards call this insulation reinforced.
However, the designer forgot that the setup may be used for more than a few minutes during testing, and within the first 14 days, dust will accumulate inside. Likewise, aging, temperature cycles, and humidity will degrade the properties of the circuit board until the insulation fails.
What’s gonna happen? The device will still work, no flames, no warnings. But the 12-volt control circuit could kill you if touched.
Although it is a kit that has been produced in the hundreds, it has probably never undergone any safety evaluation – let alone testing. Otherwise, this fundamental problem would surely have been discovered.
What to look out for when designing a device?
Whether you’re making a prototype or finalizing a finished product, keep safety in mind.
- Electrical safety. Insulation is the key. In general, equipment should survive even one failure and still be safe.
- Fire safety: even a small battery can cause a fire. Even non-mains circuits can set something on fire. Either we need to limit flammability, hide flammable elements in a non-flammable enclosure, or limit the power in the circuit so it doesn’t have the power to ignite anything.
- Functional safety: will anyone get hurt if a device or control fails? Will it always shut down even if a circuit fails?
Use the correct standards when designing equipment. Retest or get certified for anything that is safety critical.
Or ask our team to help you design your facility. We can build everything from scratch, or just check your design and fix weak spots: for this we offer an independent design review.
Our experienced developers can identify potential risks before they cause problems in practice.
