Rotary switch - alternatives

[CamB]

I've had my Storm set up (but not used in anger) with a 6 position rotary switch set up with resistors (ie a voltage divider). There's another post somewhere with what I did. The purpose was to use it to switch between boost levels and also using a virtual auxiliary to switch other stuff in various positions (eg different fuel and ignition maps for first 3 positions vs last 3 positions. It seemed to work well on my workbench.

Being a G4 storm, I am short of inputs. I have TPS, wideband, oil pressure and want to add fuel pressure, so have been trying to think of a way to get the same rotary switch functionality into a DI. I've ended up going frugal by buying one of these (for US$0.99 delivered, different seller) on Ebay:

http://www.ebay.com/itm/NE555-Pulse-Frequency-Duty-Cycle-Adjustable-Module-Square-Wave-Signal-Generator-/271251079422

I have replaced the potentiometer that controls frequency with my rotary switch (which is similar in overall resistance to the potentiometer) and now can have a frequency output in 6 steps of 17hz to 30hz. I have powered the unit with the Storm's +5v and its a DI set as "Speed" with a sensible divider. It seems to work ... at least on my workbench. 

Basically my question is whether this unconventional approach has pitfalls. My concerns are:

- it only cost 99c

- I needed to use the +5v because without a regulated supply the frequency was changing (on +12v battery voltage)

- the unknown - basically is there any reason to think this wouldn't be a reliable way of doing this. My electronic knowledge is pretty limited...

Random supplementary question - I have configured an auxiliary output for a warning light by selecting SW Cond =  Engine Limits and "1" for the engine limit. I am hoping this means the light will come on if any of the Limits are triggered. Can anyone confirm?

[Scott]

Hi Cam,

We think this should work. One thing to consider is what happens if the device fails. I'm expecting that it will then output 0 Hz, and so it may be worth adding a row on your able for this, or verify that the lowest (17 Hz?) line is used.

Scott.

[CamB]

Thanks for getting back to me. That's a good idea to consider what if it fails (and I should check, but hopefully it is a zero and not super high frequency) - at the moment if it went below the lowest row it would presumably stay there.

That'd be OK as I think I am always planning on having the lowest row as the most conservative setting (for now I'm actually planning position 1 as a sort of limp mode, for crap fuel or some other mechanical issue, so low boost, slightly lower timing, etc)

[CamB]

Sorry - also the supplementary question:

Random supplementary question - I have configured an auxiliary output for a warning light by selecting SW Cond =  Engine Limits and "1" for the engine limit. I am hoping this means the light will come on if any of the Limits are triggered. Can anyone confirm?

Thanks!

[CamB]

Random supplementary question - I have configured an auxiliary output for a warning light by selecting SW Cond =  Engine Limits and "1" for the engine limit. I am hoping this means the light will come on if any of the Limits are triggered. Can anyone confirm?

Never mind - I looked in the G4+ help file and found the following which confirms what I hoped:

Engine Limits - True when RPM Limit, MAP Limit, Speed Limit, GP RPM Limit 1 or GP RPM Limit 2 are active.The value of Engine Limits has no effect.