Mod for those with HomeLink (v.long)
Re: Mod for those with HomeLink (v.long)
Havent gotten around to hooking it up. Mainly becasue i dont have anything to use with it yet, maybe if i ever find some fogs i like or somehting like that ill get around to it. Sorry
-----------------------------------------------------------------------
-----------------------------------------------------------------------
Registered User
Joined: Jun 2004
Posts: 75
Likes: 0
Re: Mod for those with HomeLink (v.long)
Hey no prob, Judging by the reviews it seems that it picks up alot of interference from other cars , Maybe shortning the range on it can help with that, I will be trying an aftermarket alarm module to see if our homelink can adapt to it.
Registered User
Joined: Sep 2004
Posts: 2
Likes: 0
Re: Mod for those with HomeLink (v.long)
I found one of these mirrors on ebay. Unfortunately, it didnt' come with installation instructions or a harness. Would someone be kind enough to tell me which pin goes to what? :-)
Registered User
Joined: Nov 2004
Posts: 1
Likes: 0
Re: Mod for those with HomeLink (v.long)
Dude, this is an awesome concept with lots of potential utility. I'm electronically retarded though. I was just thinking that it would have to be easier than that. I bet you could program the signal from a toll-pass without having to keep it in the car. Also, what other things emit similar signals that may be utilized by pressing the homelink? I know I'm sort of babbling, but I really want to put mine to use considering I don't have a garage or gate. Let me know if anybody knows of any other cool uses. Also, if anybody lives in the DC area, I'll pay plenty to have a DVD hooked up to my navi with a homelink button as the toggle. That would be sweet.
Michael
2003.5 DG G35 Coupe Leather/Navi/Aero/Sport <P ID="edit"><FONT class="small"><EM>Edited by pavlov6 on 10/22/04 10:29 AM.</EM></FONT></P>
371268-London.JPG
Michael
2003.5 DG G35 Coupe Leather/Navi/Aero/Sport <P ID="edit"><FONT class="small"><EM>Edited by pavlov6 on 10/22/04 10:29 AM.</EM></FONT></P>
371268-London.JPG
Thread Starter
|
Registered User
Joined: Feb 2003
Posts: 7
Likes: 0
Mod for those with HomeLink (v.long)
Mod for those with HomeLink (very long)
First of all, I wanted to thank everyone on the boards for all their great ideas and insights. I’ve been lurking for quite some time now and thought it was about time to contribute as I’ve benefited greatly from everyone else’s contributions.
My A/T G coupe came with the HomeLink option. Although I utilize one of the buttons to control my garage door, I do not utilize the other two buttons and thought that they could be put to use without compromising any future utility of these buttons should I need them later. As a convenience, some people use these other buttons to disarm their home security system, or to turn on lights in their home prior to getting out of their car via an X10 RF receiver, but I don’t think this is such a good idea. In the event your car is stolen, the thief has your address via your registration, and access to your garage (unless you remember to reprogram the code right away), as well as whatever was programmed into your HomeLink, e.g., in the above case, your security system.
Particularly for those with leased vehicles, or anyone not wanting to modify/drill into their console to add extra buttons, etc, this modification allows for on/off control of various devices via the HomeLink buttons. I utilize this device to turn off the VSS signal to my NAV unit so that I can access information on the long menus while the car is in motion (I know others have utilized the trunk switch in the glove compartment, or have replaced the heated seat switches, or added other toggle switches, but this allows for a stealth install, and besides, with a child seat in the back of the coupe, the lower glove compartment door is inconvenient for my wife to open when the front seat is moved up due to her beautiful long legs! hehe! I also do not like to have to reach down across the console to access the glove compartment every time I want to access more detailed NAV info and find it much easier to just reach up to the rear view mirror to activate this feature.) Anyway, this mod can also be used to remotely control power to computers or hardwired radar detectors, or any other great mods you guys have come up with.
Essentially, this mod involves adapting a universal garage door RF receiver (which will reside in the passenger foot well or any other convenient location) to control a relay (which controls the device of your choice), and programming the HomeLink in the normal way to control this receiver. As this modified garage door receiver is self contained (except for a ground wire and a 12 volt source when the ignition is on), it requires no actual modifications to the HomeLink system and so is minimally “invasive” to your car’s electronics. This allows you to use the conveniently located HomeLink buttons to control devices remotely located in your car, as well as allowing you to control these devices with RF key FOB buttons if you wish.
At first, this seemed to be a very obvious and simple idea which would be easy to implement. However, in designing this device, I ran into some initial problems which I can help you avoid. Note: this project requires some minor soldering skills and familiarity with printed circuit boards (PCB’s) and components but is easy for anyone that can put together one of those PCB hobbyist project kits (you know, the type that has all the electronic components in a bag with instructions on how to make a LED flasher, or simple robot etc.)
First of all, the garage door receiver which you utilize should be one that runs off of 12 volts DC. Many systems (such as the Genie brand universal garage door receiver with rolling code operate off of 24 volts which will be incompatible with your car’s voltage). You can check the operational voltage of the system by checking to see what kind of 120 volt AC to DC transformer is included in the garage door receiver kit. The receiver I used is the DesignTech 2 door receiver model #30023 (allows me to control both my “unused” HomeLink mirror buttons). This is available from SmartHomeUSA.com for $43.95. A single channel receiver (Model #30021) is available for $36.95 for those that only need to control one device (I know, it’s a lot cheaper to get a simple push on/push off switch or toggle switch, but this install is much more stealthy and more convenient IHMO to use).
Secondly, as noted above, you need to decide how many devices you wish to control (obviously, get the 2 garage door receiver for 2 devices, 1 garage door receiver for 1 device; they even make a 3 garage door model, but this will use up all your HomeLink buttons). Although more expensive, you may choose to get a separate 1 door receiver for each device you wish to control, as this makes installation and wiring much easier if you have devices you wish to control in different areas of your car, such as the power switch to a computer in the trunk and the VSS signal wire to the NAV unit in the front of the car. By utilizing separate receivers, you can place the receiver next to the device being controlled, thereby simplifying wiring (as long as you have a 12 volt power source nearby) and you don’t have make long wire runs to between the controlled device and the receiver (and of course, no wires needed to the HomeLink control buttons!)
Thirdly, garage door receivers provide only momentary on contacts. To provide power to devices, you need a “latching” type function, where the first push of the control button (in this case the HomeLink button) causes a relay to latch on, providing power, until you push the control button a second time, which turns off the relay, cutting power to the controlled device. You also need this latching type function to control the continuity of the VSS signal (i.e., push the HomeLink button once to turn off the VSS signal to the NAV, and push the same HomeLink button again to return it to the default on state).
The purpose of modifying the garage door receiver is to convert it from providing a momentary on switch function, to a latching on/off switch function (DesignTech does have a “hobbyist receiver model #30037" that provides this latching function but it costs $83.95 and only provides one channel of control. To control two devices with this DesignTech latching receiver would cost a whopping $167.90. For those of you less electronically inclined, this would be the easiest way to go, especially if you only wanted to control one device). By modifying DesignTech’s 2 garage door receiver with parts from a new and surplus electronics part supply store such as www.allelectronics.com, I can control two devices for about $50 total (includes both receiver and additional electronic parts).
For those of you that are more technically/electronically inclined, this is how I modified the garage door receiver. I fabricated, then attached a high current MOSFET toggle switch (with debouncing circuit) on the momentary on contacts of the garage door receiver. I then used the power output (labeled “load” on the circuit diagram) from this MOSFET toggle switch to power the coil of a DPDT relay. The VSS wire to the NAV (green/white) was clipped and each end was attached across one of the normally closed contacts of the DPDT relay (this is the only G35 wire that needs to be cut for this particular mod). If you wish, the other available contacts on the DPDT relay can be used to apply power to a tri-color indicator LED, which will glow green when the NAV unit is in normal mode, and red when the VSS is “open”, allowing you to input or access information on the NAV from the long menus with the vehicle in motion. This indicator LED is useful as I don’t always have the NAV screen out, but I would want to be sure that continuity of the VSS wire to the NAV is intact so that the gas mileage log and maintenance interval logs are reasonably accurate.
As far as the design of the MOSSFET toggle switch, I adapted this circuit from the "Toggle Switch Debounced Pushbutton" by an electronics enthusiast John Lundgren.
The circuit uses a N-channel power MOSFET to control the load, in my application, the coil on a relay, to disengage the VSS to the NAV. This circuit can also directly supply fairly large currents depending on the MOSFET used. As you can see from the circuit diagram, it is also usable in a wide voltage range (+9-18 volts) which is ideal due to fluctuations in voltages typical in an automobile environment. The IRFZ44 is a 50 amp device and the IRF10 is a 4 amp device. Other MOSFET amperages are available (all under a dollar each) depending upon your needs.
The combination (10K, 10uF and diode) on the left side of the schematic insures the circuit powers on with the MOSFET turned off and the NPN transistor conducting. These components can be omitted if the initial power-on condition is not a concern. In this initial state (MOSFET off), the voltage at the gate of the MOSFET will be near zero and the voltage on the 1uF capacitor connected to the switches will also be near zero.
When a switch is closed, the 1uF capacitor is connected to the junction of the 220 ohm and 470K resistors causing the voltage to fall to near zero turning off the NPN transistor. As the transistor turns off, the collector voltage rises and turns on the MOSFET when the voltage climbs above about 3 volts. The drain terminal (D) of the MOSFET now moves close to ground preventing the NPN transistor from turning back on. When the switch is opened, the 1uF cap will charge through the 1M and 10K resistors to the full supply voltage. When a switch is again closed, the 1uF capacitor will cause the NPN transistor to turn back on due to the positive voltage on the capacitor applied to the junction of the two resistors (470K, 220). The MOSFET will now turn off and the drain voltage will rise to the supply voltage which in turn keeps the NPN transistor conducting with a positive voltage on the base. The circuit has now returned to the initial turn-on state.
The small (0.1uF) capacitor connected from the transistor base to ground functions to filter out noise that could cause false triggering if the switches are located far away from the circuit using long wires. If false triggering becomes a problem, either the capacitor value (0.1) or the 220 ohm resistor value can be increased to provide better filtering. Increasing these values however will increase the switching times of the MOSFET (rise and fall times) generating more heat when the MOSFET changes state. This is probably not a problem with small loads of a couple amps or less, but may be a problem at higher load currents.
Unfortunately, in my enthusiasm to complete this project, I neglected to take photographs. However, when I get the time, I will disassemble everything and document step-by-step the assembly of all parts if there is enough interest in this project. Sorry for this extremely long post.
Have fun, and thanks to all again for all the great G35 project ideas.
141762-Modified toggle circuit.jpg
First of all, I wanted to thank everyone on the boards for all their great ideas and insights. I’ve been lurking for quite some time now and thought it was about time to contribute as I’ve benefited greatly from everyone else’s contributions.
My A/T G coupe came with the HomeLink option. Although I utilize one of the buttons to control my garage door, I do not utilize the other two buttons and thought that they could be put to use without compromising any future utility of these buttons should I need them later. As a convenience, some people use these other buttons to disarm their home security system, or to turn on lights in their home prior to getting out of their car via an X10 RF receiver, but I don’t think this is such a good idea. In the event your car is stolen, the thief has your address via your registration, and access to your garage (unless you remember to reprogram the code right away), as well as whatever was programmed into your HomeLink, e.g., in the above case, your security system.
Particularly for those with leased vehicles, or anyone not wanting to modify/drill into their console to add extra buttons, etc, this modification allows for on/off control of various devices via the HomeLink buttons. I utilize this device to turn off the VSS signal to my NAV unit so that I can access information on the long menus while the car is in motion (I know others have utilized the trunk switch in the glove compartment, or have replaced the heated seat switches, or added other toggle switches, but this allows for a stealth install, and besides, with a child seat in the back of the coupe, the lower glove compartment door is inconvenient for my wife to open when the front seat is moved up due to her beautiful long legs! hehe! I also do not like to have to reach down across the console to access the glove compartment every time I want to access more detailed NAV info and find it much easier to just reach up to the rear view mirror to activate this feature.) Anyway, this mod can also be used to remotely control power to computers or hardwired radar detectors, or any other great mods you guys have come up with.
Essentially, this mod involves adapting a universal garage door RF receiver (which will reside in the passenger foot well or any other convenient location) to control a relay (which controls the device of your choice), and programming the HomeLink in the normal way to control this receiver. As this modified garage door receiver is self contained (except for a ground wire and a 12 volt source when the ignition is on), it requires no actual modifications to the HomeLink system and so is minimally “invasive” to your car’s electronics. This allows you to use the conveniently located HomeLink buttons to control devices remotely located in your car, as well as allowing you to control these devices with RF key FOB buttons if you wish.
At first, this seemed to be a very obvious and simple idea which would be easy to implement. However, in designing this device, I ran into some initial problems which I can help you avoid. Note: this project requires some minor soldering skills and familiarity with printed circuit boards (PCB’s) and components but is easy for anyone that can put together one of those PCB hobbyist project kits (you know, the type that has all the electronic components in a bag with instructions on how to make a LED flasher, or simple robot etc.)
First of all, the garage door receiver which you utilize should be one that runs off of 12 volts DC. Many systems (such as the Genie brand universal garage door receiver with rolling code operate off of 24 volts which will be incompatible with your car’s voltage). You can check the operational voltage of the system by checking to see what kind of 120 volt AC to DC transformer is included in the garage door receiver kit. The receiver I used is the DesignTech 2 door receiver model #30023 (allows me to control both my “unused” HomeLink mirror buttons). This is available from SmartHomeUSA.com for $43.95. A single channel receiver (Model #30021) is available for $36.95 for those that only need to control one device (I know, it’s a lot cheaper to get a simple push on/push off switch or toggle switch, but this install is much more stealthy and more convenient IHMO to use).
Secondly, as noted above, you need to decide how many devices you wish to control (obviously, get the 2 garage door receiver for 2 devices, 1 garage door receiver for 1 device; they even make a 3 garage door model, but this will use up all your HomeLink buttons). Although more expensive, you may choose to get a separate 1 door receiver for each device you wish to control, as this makes installation and wiring much easier if you have devices you wish to control in different areas of your car, such as the power switch to a computer in the trunk and the VSS signal wire to the NAV unit in the front of the car. By utilizing separate receivers, you can place the receiver next to the device being controlled, thereby simplifying wiring (as long as you have a 12 volt power source nearby) and you don’t have make long wire runs to between the controlled device and the receiver (and of course, no wires needed to the HomeLink control buttons!)
Thirdly, garage door receivers provide only momentary on contacts. To provide power to devices, you need a “latching” type function, where the first push of the control button (in this case the HomeLink button) causes a relay to latch on, providing power, until you push the control button a second time, which turns off the relay, cutting power to the controlled device. You also need this latching type function to control the continuity of the VSS signal (i.e., push the HomeLink button once to turn off the VSS signal to the NAV, and push the same HomeLink button again to return it to the default on state).
The purpose of modifying the garage door receiver is to convert it from providing a momentary on switch function, to a latching on/off switch function (DesignTech does have a “hobbyist receiver model #30037" that provides this latching function but it costs $83.95 and only provides one channel of control. To control two devices with this DesignTech latching receiver would cost a whopping $167.90. For those of you less electronically inclined, this would be the easiest way to go, especially if you only wanted to control one device). By modifying DesignTech’s 2 garage door receiver with parts from a new and surplus electronics part supply store such as www.allelectronics.com, I can control two devices for about $50 total (includes both receiver and additional electronic parts).
For those of you that are more technically/electronically inclined, this is how I modified the garage door receiver. I fabricated, then attached a high current MOSFET toggle switch (with debouncing circuit) on the momentary on contacts of the garage door receiver. I then used the power output (labeled “load” on the circuit diagram) from this MOSFET toggle switch to power the coil of a DPDT relay. The VSS wire to the NAV (green/white) was clipped and each end was attached across one of the normally closed contacts of the DPDT relay (this is the only G35 wire that needs to be cut for this particular mod). If you wish, the other available contacts on the DPDT relay can be used to apply power to a tri-color indicator LED, which will glow green when the NAV unit is in normal mode, and red when the VSS is “open”, allowing you to input or access information on the NAV from the long menus with the vehicle in motion. This indicator LED is useful as I don’t always have the NAV screen out, but I would want to be sure that continuity of the VSS wire to the NAV is intact so that the gas mileage log and maintenance interval logs are reasonably accurate.
As far as the design of the MOSSFET toggle switch, I adapted this circuit from the "Toggle Switch Debounced Pushbutton" by an electronics enthusiast John Lundgren.
The circuit uses a N-channel power MOSFET to control the load, in my application, the coil on a relay, to disengage the VSS to the NAV. This circuit can also directly supply fairly large currents depending on the MOSFET used. As you can see from the circuit diagram, it is also usable in a wide voltage range (+9-18 volts) which is ideal due to fluctuations in voltages typical in an automobile environment. The IRFZ44 is a 50 amp device and the IRF10 is a 4 amp device. Other MOSFET amperages are available (all under a dollar each) depending upon your needs.
The combination (10K, 10uF and diode) on the left side of the schematic insures the circuit powers on with the MOSFET turned off and the NPN transistor conducting. These components can be omitted if the initial power-on condition is not a concern. In this initial state (MOSFET off), the voltage at the gate of the MOSFET will be near zero and the voltage on the 1uF capacitor connected to the switches will also be near zero.
When a switch is closed, the 1uF capacitor is connected to the junction of the 220 ohm and 470K resistors causing the voltage to fall to near zero turning off the NPN transistor. As the transistor turns off, the collector voltage rises and turns on the MOSFET when the voltage climbs above about 3 volts. The drain terminal (D) of the MOSFET now moves close to ground preventing the NPN transistor from turning back on. When the switch is opened, the 1uF cap will charge through the 1M and 10K resistors to the full supply voltage. When a switch is again closed, the 1uF capacitor will cause the NPN transistor to turn back on due to the positive voltage on the capacitor applied to the junction of the two resistors (470K, 220). The MOSFET will now turn off and the drain voltage will rise to the supply voltage which in turn keeps the NPN transistor conducting with a positive voltage on the base. The circuit has now returned to the initial turn-on state.
The small (0.1uF) capacitor connected from the transistor base to ground functions to filter out noise that could cause false triggering if the switches are located far away from the circuit using long wires. If false triggering becomes a problem, either the capacitor value (0.1) or the 220 ohm resistor value can be increased to provide better filtering. Increasing these values however will increase the switching times of the MOSFET (rise and fall times) generating more heat when the MOSFET changes state. This is probably not a problem with small loads of a couple amps or less, but may be a problem at higher load currents.
Unfortunately, in my enthusiasm to complete this project, I neglected to take photographs. However, when I get the time, I will disassemble everything and document step-by-step the assembly of all parts if there is enough interest in this project. Sorry for this extremely long post.
Have fun, and thanks to all again for all the great G35 project ideas.
141762-Modified toggle circuit.jpg
Thread
Thread Starter
Forum
Replies
Last Post
