The Magical Cheap Connector You Cant Find On Digikey
Originally posted on LinkedIn. Find the post here:
Recently, my hotel room’s mini fridge had a flickering light and a glass door. So instead of going to sleep, I discovered something awesome. I couldve called reception, but where’s the fun in that? Instead I took apart the light assembly to try to see what the issue is, and this is what I found.
As an electronics engineer, and especially as someone who likes working on mass manufactured consumer goods, every little bit of money saved per unit saves the company millions. and here, with ONE connector, a ton of money was saved!
In the photos you can see a connector that was new to me. It belongs to a family called “RAST 2.5”, and is made specifically to be as standard and cheap as possible while still being reliable enough even for automotive applications. It replaces the plastic half that is supposed to be on the printed circuit board (PCB)… with the PCB itself! Saving not only the component cost, but also the process cost of soldering it.
But wait, it gets better! If you grab any usual cable that connects to a pcb or those you find in cars, you’ll find a plastic plug. This isnt one part, instead, the wires are each stripped, placed inside the metal pins (called terminals), crimped, and then individually inserted into the plastic housing to form the plug (two unique part numbers per plug, excluding the receptical that the plug goes into).
That’s where the designers of this connector found yet another opportunity. Instead of the 3 part plug/terminal/receptical you normally find, here there is no terminal for the wires to go into first. The UNstripped wires are placed into the connector, a plunger is pressed in, and the connector itself cuts the plastic insulation and contacts the wires (this connection method is called IDC). This one part is cheaper than buying the normal 3, and installing it is a faster and cheaper process.
In the first photo you can see the IR LED/Reciever that are used to detect the door being closed, in the next, you can see how the single layer board is held in the plastic without screws (saving even more cost) and with two of those connectors on it, and in the last, here’s how cheap these connectors are when you buy “just” a thousand. Now imagine buying a million.
Turns out that even a vacation can be educational, and the light stopped blinking after I took it apart and put it back together. So Novotel Hotels, sorry and you’re welcome, I guess 😅