dome light circuit

[Edd]

Hey my p71 : <p>I thought that you had that all going some time back. Seems like Ron sent you to a link but it was all flaming and referring to another link that someone had made much harder to find.<p>Now refer to this schematic:<p>http://www.electronic-circuits-diagrams ... ages/3.gif<p>
Instead of requiring the use of unnecessarily high values of capacitance across relays or transistors it is using the higher impedance of an op amps input to scale down to a miniscule 22 ufd storage electrolytic cap. Its adjustable shunt resisance VR1 trim pot scales the decaying time of the capacitor (Dome dimming rate) . While VR2 trim pot is setting the initial brightness of the dome lamp(s).
If this doesn’t properly link to the URL for you, hit me at my Comcast ID and I’ll E- mail you the schematic.<p>73's de Edd
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.... <the gold dust twins

[myp71]

Hi <p>Mike-- I was using a coil relay for this instead of a solid state.I really would still like my dome light to fade I might try this other circuit that was posted here but if this circuit for the dome light fade does not work for some reason,I will hook up your circuit idea but this time using a solid state relay
Thanks again Mike<p>also how many amps-watts can the 2n3055 handle?

one more question using Edd Whatley circuit idea this circuit looks like it controls the dome lights through the 2n3055 using ground (gnd)
can that be changed to the + side of the dome light?Because the dome lights that I have are grounded through the truck body so it will be hard to cut the gnd off to control the lights that way through ground.<p>[ November 27, 2003: Message edited by: my p71 ]</p>

[Mike]

Ok, well just so you know, I used a coil relay also, not a solid state. Actually, solid states probably won't work. They are a voltage operated device, and the caps will keep the voltge, just at no amps, even after discharged. But I guess they can't run without current. I don't really know. I haven't used one before. <p>I'll see if I can throw a fade circuit together for you.

[Mike]

Just thinking, how about a pushbutton connected to the 12V and a regulator (7805 maybe?) then through a small cap, such as 1,000 uf then to a optocoupler? The LED in it wiill fade out when the door is shut and the resistance of the cds cell will go up. You may need circuitry to power the light, or to switch it off when it is dimmed so you aren't always draining the battery.

[myp71]

Yeah, that might work <p>Also Mike, the circuit that Edd Whatley posted for this circuit using the 2n3055 to me it looks like it uses the gnd to turn on the dome light would you look @ this circuit for me and be sure that it uses the negitive switching type?<p>[ November 29, 2003: Message edited by: my p71 ]</p>

[Edd]

Myp71:<p>I didn’t exactly interpret if you were using the stock interior light(s) or you had installed some on your own.
If the latter is the case you would certainly know about the power routing of the lamps ground.
Most dome lamps I have seen ~15 years use radial folded wire terminals or a longer axial lamp envelope with the wire terminals at both ends….none of the domed glass globes and their metal bayonet shell sockets of the past.
Also, for many a year lately, the norm seems to have been the carrying of most grounding through the wiring harness by virtue of the widespread use of more plastic/fiberglass/composites in the insides of vehicles. Seems like the last door /hood/trunk pressure switches that I have seen used that grounded itself to the frame were the ones that custom alarm installers use in those applications.
Your Pwr NPN 2N3055 and its PNP twin , the 2N2955 is at:
http://220.130.99.70/pdf/2n3055.pdf
Basically its an old workhorse with a 60 Vrating @ 15A max@115 W and a Dc Beta spread of 20-70 at a 4A drain.
If you were always popping in and out thru the door, minimal heat sinking might be permissible, but if someone was to stand there with the door open the unit would be passing that 4-6 Amps thru it for that duration , so U need to plan for worst case.
If you still have chassis ground to the lamps and can’t open that line, I looked thru my circuit archives and found this web reference schematic at Charles site:
http://www.wenzel.com/pdffiles/dimmer.pdf
Using the 741 delay circuit and, referrring Charles above circuit , from the2N4401 to the right, if you were to feed Vr2’s wiper contacts into the right end of the new circuits 2N4401 base, that should interface with the other type of lamp grounding that you could have. The PNP power xstrs collector output feeds to your dome lamp(s). A 2N2955,or TIP36C are two other alternate PNP BIPOLAR power xstrs that could also be used.
So it seems like the control electronics needs wiring interconnect to [1] (Negative Ground), [2] ( the dome lamp(s) [3] (12VDC) and [4](Door Switch(es) and I feel the later two would be the most difficult routing ……according to whether the door switch(es) open the 12V or the ground circuit line.<p>73's de Edd
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<p>[ December 01, 2003: Message edited by: Edd Whatley ]</p>

[myp71]

Thanks Edd for your help.<p>My truck that I want to put this dome light fade circuit on is a 01 ford ranger and for some reason ford has come up with this genius idea of reed switches for the dome light switch that can not be found to get to the wiring.Also some how the ground switches over to positive when the doors close. <p>[ December 01, 2003: Message edited by: my p71 ]</p>

[Edd]

MYP71:
I pulled a reference wiring diagram of your 2001 Ranger (Std Cab ?) at our Automotive Technologies Instruction division. Not having visually seen the “Courtesy lamp cluster”, the schematic might suggest there being one center rear interior lamp and adjacent Map 1 and Map 2 lamps skewing illumination off to the R&L . The wiring diagram confirms the lamps ground line not being switched, but instead, the switching of the +12VDC to the “Courtesy lamp cluster”. If there is a manual switch on the plastic housing I would suspect just a leaf switch with a plastic dimple on the rear of a sliding plastic knob mech actuating it. The std schematic symbol of a mag reed sw is not utilized, instead, just a common SPST switch designation.
Seems like the “interior” lamp is hooked to some exotica… e.g….. the GEM module that times out after 10 minutes, the manual switch on the lights dimmer control, a speed sensor on the transmission that de activates it after a certain speed,and the door chime.
For an online reference go to:
www.alldatadiy.com
Sequence thru…….: DEMO*1993 TRUCK RANGER*LIGHTING AND HORNS*COURTESY LAMP*ELECTRIC DIAGRAMS* REG CAB (?)* ZOOM……(might take a wait or refresh back around the electric diagrams or later, since there is so much data being crunched)
There is not much variance on the 2001’s data, seems like the wire color coding on the ’93 light line up at the top light supply line was LtGn/Yel then, but is now Lt Gn/Orange on the 2001. Your single lamp shows a Blk/Lt Blu feed line and a Blk as its ground on the wire color coding.
The Map 1 &2 lamps , are fed from the Lt GN/Orange switched light line, and come out as that color at the lamps sockets with a Blk as its ground.<p>73's de Edd
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[myp71]

Thanks Edd for all your help really helpful<p>
Myp71
Ryan

[myp71]

Leave it to Ford to have all of this fancy G.E.M module and another module to tell when the vehicle is in motion to turn off the domelights but Ford can not put a domelight fader on their trucks.