EYE ON NPI – E200 Series E-Stop Pushbutton Switches

Adafruit Industries

This week's EYE ON NPI will make you Stop! In the Naaaaaaaaaaame of Love (https://www.youtube.com/watch?v=9JiS02O4fEk) but will never break your heart - it's E-Switch's E200 Series E-Stop Pushbutton Switches (https://www.digikey.com/en/product-highlight/e/e-switch/e200-series-e-stop-pushbutton-switches). These are two small emergency stop switches that are durable, ergonomic, safe and easy to use! Both have immediate "slam to stop" and "twist to re-start" functionality. One has a classic mushroom-domed top and the other is a longer grippy wheel that comes with a optional center illumination by neon bulb or LED. Just this week we were talking with someone working in safety design and recommended The Design of Everyday Things (https://jnd.org/books/the-design-of-everyday-things-revised-and-expanded-edition/) a book that covers how to design 'obvious' things in the real world - like how doors pull when entering and push to exit a building, so that folks trying to escape a building in a panic don't get trapped. A lot of the design decisions have been learned by hard lessons: people getting injured or dying... that's why we have things like building codes and engineering certifications such as those for medical devices (http://sunnyday.mit.edu/papers/therac.pdf). Even when we do our best to design safety margins, redundancies and interlocks, there's always the chance that something will go wrong. Especially when designing robots, machinery, lasers, or some other "Machine that does not know the difference between metal and flesh, nor does it care" (https://www.reddit.com/r/Machinists/comments/sg9wct/i_made_a_sticker_for_the_lathe/) That's where you definitely want to add in an emergency stop switch, also known as a kill switch. Wire this up in series with your main power input and no matter what happens with your firmware or interlock or other secondary safety features, you will cut the power instantly. The brilliance in this design is that you push or slam down on it to open the contacts but then you need to twist to reconnect. This means folks can't accidentally turn it on again by pressing again, there's no chance of it bouncing closed, and you can immediately verify the state by pressing it again. The E-Switch's E200 Series E-Stop Pushbutton Switches (https://www.digikey.com/en/product-highlight/e/e-switch/e200-series-e-stop-pushbutton-switches) are both rated for 250VAC 5A, 125VAC 8A or 24DC 6A with IP65 dust-tight (https://en.wikipedia.org/wiki/IP_code). Simply drill a 16mm hole in your enclosure to mount. The contacts are shrouded to minimize risk of cross-contact, use 0.11"/2.8mm spade quick contacts (https://www.digikey.com/en/products/detail/te-connectivity-amp-connectors/2-520083-2/289211) to connect. Whichever variant you choose, you can add a stylish kill switch to your next design from a trusted switch manufacturer that will keep your users and products safe from each other. And best of all, DigiKey has both E-Switch E200's (https://www.digikey.com/short/5tvqhj4b) in stock right now for immediate shipment! Order today and you'll be E-Stopping by tomorrow afternoon. And check out the manufacturer's video at https://www.youtube.com/watch?v=6TY-6tbsB0E