Discovering the Wires

August 2nd, 2015

I opened up the current manual bed controller so we could have a look inside. What we found was a circuit board showing traces from each of the buttons to each of the wires in the main cord that connects the controller to the power source. We documented which wire corresponds with each button (and subsequent bed function) and took detailed notes so that we could find which wires would then correspond on the 9-pin serial connector (shown below).

We found out the following:

- Bed up is the white wire

- Bed down is the red wire

- Knees up is the green wire

- Knees down is the brown wire

We then looked inside the connector to see which wire went to which hole. Each of the five (including the black ground wire) were located on the top row on five pins. From left to right, they were as follows: brown, green , black, white, red

We also assigned each of the relays on the relay board a specific function, so relay 1 = bed up, relay 2 = bed down, relay 3 = knees up, and relay 4 = knees down.

We tested to see if the LEDs by each relay on the relay board would light up with an electronics testing lab, as shown below.