For my road test of the CapSense MBR3 I want to see how suitable these sensors are for a workshop environment. For that reason I'm conducting two key tests. Firstly one using different types of gloves, and secondly one with different thicknesses of front panel.
Although I don't wear gloves for most of my workshop activity they are essential when welding or working with chemicals.
I configured the board so that each of the switches had a different sensitivity, the threshold was set to automatic. The sensitivity was noticeable when I tested it without gloves, button 4 required the finger to be firmly pressed on the switch to register. I also turned on the buzzer as I thought my gloves might obscure the LEDs. For all of the tests I used my left forefinger to have consistent results. I did read in the documentation that for automated testing it is possible to use a small metal disk instead of a finger but I've not tried this.
I tested with three different kinds of gloves, all are electrically insulating.
- Material: PVC coated cotton
TIG Welding Gloves - Material: Leather
- Material: Leather with cotton liner
The PVC gauntlets are approx. 0.5mm thick and have a ridge at the finger tip. When the finger tip with buttons 1 and 2 they worked correctly but button 3 was intermittent and button 4 did not register. When I used the flat of the finger all four switches could be operated.
The TIG gloves are thin leather approx. 0.5mm thick, there was also a seam at the fingertip and again buttons 1 and 2 worked correctly with 3 intermittent and 4 none operational. Again with the flat of the finger all 4 switches worked correctly.
The thick leather welding gauntlets are approx. 2mm thick and also had the largest seam of all of the gloves and only button 1 could be activated. With a flat finger button 1 and 2 were operational, button 3 barely worked and 4 did not work.
For my final test I thought I'd check if the 10mm vs. 11mm pad size made a difference. For this test I used buttons 1 and 3 only and set the sensitivity low at 300fF. I also used the thickest gloves. The size did make the difference with button 1 non-responsive and button 3 reliably working.
So my conclusion is that the gloves do make a difference. With suitable configuration of the sensitivity and by increasing the sensor size the CapSense switches can be used with common workshop gloves even those with thick seams. The maximum recommend sensor size is 15mm so I think I'd make the switches this size as the diameter of a finger in a glove is about 20mm and hence that size would be ergonomic.