Mag Clickie Cycling Through Modes

[SnowplowTortoise]

I'm having trouble with a recent Mag mod. Here's the set-up: Mag 4C, DHS heatsink, SSC P4, 1050mA 7135 multimode driver from DX (submerged in arctic silver in the back of the DHS), 4 NiMH C. It works fine – just like the 2C's and 3D's that I have converted before, except for one thing. Each click of the clickie switch changes the mode of the driver. As it clicks once on the downward motion and once coming back up, it ends up changing modes three times every time I turn it on or off. It makes it impossible to select the right mode.

I've never had this problem before. I've use the same driver on the 3D's I've converted and similar drivers on the 2C's, so I can't imagine it's a fundamental flaw with any single part – maybe just some manufacturing tolerance with the driver or the switch that is not right. Anybody have any experience with this problem?

 

[Upplyst]

I have had the exact same problem when using it on a 3c Mag. I thought it was the forward clicky that caused the difficulty of mode switching. It seemed as I always ended up with strobe mode no matter how I tried to click.

 

[zambai]

This sounds to me like a switch debounce problem. When a switch makes or breaks contact, there are lots of little tiny makes & breaks going on (in the kHz range, I believe), which on an oscilloscope would be very visible. Unfortunately, it's also very visible to your driver, which "sees" 2 or more ONs and OFFs for a single switch press. Adding a low pass filter for switch debounce would probably fix this.

...Let's see here, sophomore circuits class:sweat:... I know a low pass filter is a resistor in series with a capacitor parallel to ground, and its time constant is 1/(2*Pi*R*C), so maybe something like a 100uF cap and a 2 Ohm resistor (for a 800Hz low pass)?

Really bad schematic (the dots are just to get everything justified):

<battery>----<switch>----<resistor>----------<regulator Vin>
....................................................... |
....................................................... |
................................................ <capacitor>
....................................................... |
....................................................... |
.................................................. <ground>

Warning: You don't want a large resistor in series with the current from the batteries. Voltage will be lost across this resistor.

This seems like a viable solution, but maybe I'm way off here, someone please back this up (or tell me I'm full of crap).

oh, and here's a great link:
http://en.wikipedia.org/wiki/Low_pass_filter

 

[download]

That is mechanical problem, try this:
Take the MagC switch module apart, stretch the outter (fatter) spring 1.5-1.8 time longer. That make the contact more solid. And apply a few drop of Pro-Gold between each contacts. It will solve 90% of the changing mode effect.