In the first of a series of guest posts, electronics hobbiest Gary tackles connecting your own switches and sensors to the Apollo Ensemble.
“If you fancy playing around with connecting your own sensors & switches to the EnsembleHub, then knowing the basic connection details is a good start.
I’ll start with the variable sensor 1 & 2 conections. These two ports use 1/4″ stereo plugs, comprising of +5Volts out, a signal return/variable input (0-2.3Volts for 0-100% response), and finally a 0V connection.
I measured the input response to the hub via a 10-turn pot and a calibrated DVM to get the 0-2.3v information, so if your sensor output is a higher voltage then you’ll need to use a couple of resistors to control it…A handy link to have to help you work out the resistor values is: electronics2000
If you look at the image to the right you can see the 3 connections of the stereo jack, from top to bottom you have “tip” “ring” and “sleeve”
Tip = +5volts output from hub
Ring = variable signal input 0 – 2.3volts
Sleeve= 0volts / ground if you prefer
Next up we have the switch inputs 1, 2, 3 & 4, which are on 3.5mm mono jack plugs. These are easier to interface, as there are only two connections dealing with an on or off state…BUT it is worth noting that the voltage output and wiring configuration IS NOT like the variable inputs.
All you are doing in effect is shorting 3v3 to 0volts and that triggers the switch in the software.
Tip = 0volts / ground
Sleeve = 3v3 output
I hope this gives you enough details when considering building and connecting anything to your hub!”