Brigadoon - An Occasional Corner on the Internet
DIN Connectors
Designed by Mark Little
8-pin mini-DIN connectors provide a relatively high wire density and can be obtained relatively cheaply from surplus component sellers from time to time. Given that many of the projects on this website deal with sensors, it is prudent to make a standard about what can be expected on each pin of the connector. After looking at wide range of cables with 8-pin mini-DIN connectors, it because obvious that there is not a common pin-out standard even for the earth connection. As a result, this leaves the way open to use a bespoke pin numbering scheme. The table below shows the standard pin-out wiring scheme adopted for projects on this site.
8-Pin Mini-DIN Connectors

Pin Function
1 Signal Line 0. The line may be an input or output as required by the project.
2 Signal Line 1. The line may be an input or output as required by the project.
3 Power Earth Connection. Unless Pin 4 is used, this is the signal return as well.
4 Signal Earth Connection - May be paralleled with Pin 3 if a separate earth is not required.
5 +5V Power Rail
6 Signal Line 2. The line may be an input or output as required by the project.
7 Signal Line 3. The line may be an input or output as required by the project.
8 Control Line. The control line may be an input or output as required by the project.
For the sake of standardisation, this cable standard sets the default power supply voltage as +5V.

The standard does provide the potential for two (2) earth connections, a power rail ground and a signal ground. A separate signal ground should be used when the voltage drop on the Earth wire would be sufficient to upset the reading between a signal line and the earth at the far end of the cable. The can be done by either paralleling the two wires or using pin 4 as an separate signal earth connection (if the device supports that configuration).

A maximum of four (4) signal lines can be passed via the cable. The direction of the signal (and whether it is analogue or digital) is decided by the project. The proviso is that anything connected to these signal lines pins must be capable of withstanding +5V volts and must not output more than +5V. It is expected that the output signal should be uni-polar, unless protected by a non-polarised serial capacitor capable of handling 12V.

A single control line is provided. Like the signal lines, the direction of the control signal is up to the project, as long as anything that connects to this lines is capable of handling a voltage between 0V and +5V.