Accessing Beaglebone serial port while using a cape – DIY low profile pin header connector
I am currently using BeagleBoneBlack for logging some data. The system is designed to work autonomously so normally no wired or wireless connection is available. For testing purposes however diagnostic data can be output to the serial port of the beaglebone. Also a serial console is available at that port. I use ttyO0 which is enabled by default and needs no extra configuration. For pin locations and how to enable serial ports, you should check here.
The beaglebone serial port is located on the J1 connector (Pins 1=GND, 4=RX, 5=TX). This connector however is not on the outer expansion connector and is covered by any capes you might be using. Usually I connect to the pin headers using dupont connectors however under the cape there is just not enough place for one. Of course there is always the ugly way of soldering connections to the bottom of the BBB board, however you may damage the board by doing this. Another way is to get a low profile female pin headers, however I could not get one locally (= fast) so I chose to “convert” a classic dupont connectors to a low profile one.
To do this you need a few 1p-1p dupont cables. On the end that will be connecting to the beaglebone remove the connector housings as we will not be able to use them.
Place, but do not heat yet, some heatshrink tube over the receptacle and to the cable before bending (this will be later used to insulate a part of receptacle). Then carefully bend the receptacles 90 degrees.
They should be bent just after the end of connector, the inner part of the bend should be where the connector is solid. The side metal part of the receptacle will partially break, however there will still be enough metal to hold it together. You should apply a small amount of solder to the inner side of 90 degree bend to make the receptacle solid enough for normal handling (so it won’t split at the bend) – image shows the connectors with solder already applied (you can see that the bend is a bit shiny).
After you are satisfied with the connector you can now slid the heatshrink tubing back over the bent connector.
If you didn’t place the heatshrink tubing before bending the connector the only way to get it on is to split the cables, remove the dupont housings on the other end of the cable and put the heatshrink tubing on from the other end. Heat the tubing so that it binds to the metal connector. And here you have it 🙂 quick and dirty low-profile pin header connector. Connected to a BBB:
And still connected with a cape mounted on the BBB:
Alternatively of course you can always use the normal low-profile connector.