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JohnNeiferd · 05-22-2011, 08:14 PM

Hi,

My question: What is the maximum current the vehicle speed sensor line (for the MPGuino) should see? 0.25 amps? more? less? I want to make sure I don't let to much current through the new vss wire and damage my MPGuino. Is there a minimum required current for the MPGuino to pick up the signal? If so, what is that minimum current?

Long story short, I am adding another VSS signal for both MPGuino and my aftermarket cruise control in my vehicle instead of using the stock VSS signal.

My stock VSS is a reed type switch. An open switch has +12v on one side and ground on the other and magnet from speedometer makes the reed switch make contact and completes the +12v circuit.

I am making a similar system using a bicycle speedometer magnet sensor, and two magnets on my cv shaft. It is basically a reed type sensor, open circuit without a magnet, and completed circuit with magnet. I am going to feed +12v to one side of the wire, and the other wire goes to ground. I'll be using a resistor to limit current flow through the wire.

My question again...: What is the maximum current the vehicle speed sensor line (for the MPGuino) should see? 0.25 amps? more? less? I want to make sure I don't let to much current through the new vss wire and damage my MPGuino. Is there a minimum required current for the MPGuino to pick up the signal? If so, what is that minimum current?

05-22-2011, 08:14 PM	#1 (permalink)
JohnNeiferd EcoModding Lurker Join Date: Jul 2008 Location: Ohio Posts: 28 Johnny's Metro - '93 Geo Metro 4-Door Hatchback 90 day: 47.5 mpg (US) Jetta GLS TDI - '01 Volkswagon Jetta GLS 90 day: 45.83 mpg (US) Thanks: 0 Thanked 0 Times in 0 Posts	MPGuino: Max Current for VSS Line? Hi, My question: What is the maximum current the vehicle speed sensor line (for the MPGuino) should see? 0.25 amps? more? less? I want to make sure I don't let to much current through the new vss wire and damage my MPGuino. Is there a minimum required current for the MPGuino to pick up the signal? If so, what is that minimum current? Long story short, I am adding another VSS signal for both MPGuino and my aftermarket cruise control in my vehicle instead of using the stock VSS signal. My stock VSS is a reed type switch. An open switch has +12v on one side and ground on the other and magnet from speedometer makes the reed switch make contact and completes the +12v circuit. I am making a similar system using a bicycle speedometer magnet sensor, and two magnets on my cv shaft. It is basically a reed type sensor, open circuit without a magnet, and completed circuit with magnet. I am going to feed +12v to one side of the wire, and the other wire goes to ground. I'll be using a resistor to limit current flow through the wire. My question again...: What is the maximum current the vehicle speed sensor line (for the MPGuino) should see? 0.25 amps? more? less? I want to make sure I don't let to much current through the new vss wire and damage my MPGuino. Is there a minimum required current for the MPGuino to pick up the signal? If so, what is that minimum current?