turbodog
Donating Member
Multi-input guages with dimmer circuit (long)
Multi-input guages with dimmer circuit (long)
OK, here's a brain dump. Parts list for one guage (4 inputs):
all resistors can be cheapo 1/8 watt, RatShack
100 ohm
70 ohm
250 ohm
330 ohm
430 ohm (I used a 330 + 100)
a 3.2 V zener diode
a NTE 253 (or equiv) NPN Darlington pair transistor
two general purpose diodes
a 2 pole 4 throw rotary switch
two HP HLMP 2835 LED bar indicators
I got everything at allied electronics: www.alliedelect.com
Schematic (sorry, lost electronic original, this is the one I used and marked up during my assy and debug):
I suggest you get an extra LED bar unit for each guage. I ruined 2 before I got my technique perfected for this next part:
The HP LED bars come with each LED (4 per bar) pinned out seperately. You must wire them in series per this schematic close-up:
This is a pain in the butt. The right way would be to etch a little circuit board to do this, then solder the LED unit to the circuit board. I figured it would be easier to just hand-wire it using ultra-fine guage wire. Now I'm not so sure. I ended up doing it under a magnifying glass, with tweezers and the daintiest soldering pencil I could find. I still ruined 2 units (by overheating the pin, probably) before I got 4 good units wired. I made each connection as close to the backside of the LED unit as possible, then trimmed the LED pins short so the finished unit will be nearly flush against the guage glass.
After wiring and testing the LED bars, I super-glued 2 together to make a stack of 4 bars. I painted them flat black (except around the LED lenses).
I soldered the grounds from each bar segment together, and soldered on one long ultra thin power wire per bar, plus one ground wire for the whole stack. So, the finished stack of 4 bars now has 5 long (6 inches or so) fine wires extending out. all these wires must exit at the bottom of the stack, as closely together as possible. I tested the units again. A 9v square battery makes a perfect test supply for a single bar (4 diodes in series).
I assembled the dimmer circuit on vector board, packing everything in pretty tight (the board for each dimmer is about 3/4 inches by 3/4 inches). For each connection in/out of the dimmer (12v, ground, guage lamps, and output to switch), I added a length of fine wire and left it dangling. I wrapped the finished, tested dimmer in electrical tape to prevent shorting. At this point, it is a 3/4 inch cube with 4 wires dangling.
I set the bar stack into the face of the guage, and marked the inside edge of the bezel at the LED wire bundle. I then carefully lined up a dremel-style bit (maybe 1/32) so to drill a hole from the back edge of the bezel (where the bezel is swaged over the guage housing) out to the front inside edge of the bezel where I had marked it. I drilled 3 holes side by side then used an awl and jeweler's file to form a slot from the 3 holes.
I then loosened the movement from the housing (nuts on back of the guage), got the movement as far to one side as possible, and vacuumed out the drill flakes using a keyboard vac with shrink tubing as an extension, thru the hole for the light bulb.
I then fed the LED unit wires thru the bezel slot, from front to back. There is a rubber gasket in there that hinders this process. Stripping and solder-tinning an inch of wire makes them stiffer and helps them poke thru the gasket.
with the wires fed thru, I then test fit the guage in the pod (not pushing it in all the way) and mark where the wires will want to go thru the pod. I removed the guage and carefully filed a slot in the pod plastic to allow the wires to pass thru alongside the guage body when it is installed in the pod.
I then test-fitted the empty pod to the pillar, and marked a spot where the switch will extend vertically down. I drilled the holes for the rotary switch.
I attached the LED bar stack to the guage face, using a dab of silicone caulk. I carefully positioned it so it would be level with the guage graphics, and set a weight on it during the caulk cure. I touched up the flat black paint, and added a tiny filler panel (sheet styro-plastic from a hobby shop, painted black) to fill in between the flat bottom of the LED stack and the curved inside edge of the bezel. I attached the filler panel with a tiny dab of caulk.
I installed the guage in the pod, then soldered the LED wires to the switch contacts. I soldered light guage wire to the guage sender contacts on the switch.
In fact, I used the multi-conductor comm wire from which I got my LED wires. This makes a tidy bundle for the 8 wires going out to various senders. I terminated the light guage wires in the driver side fender, beside the wiper washer reservoir. I put in-line connectors to 14 guage wire, and ran the 14 guage wire to the senders.
Back to the guage. With all wires soldered to the switch, I connected the switch output to the guage input, then mounted the switch in the hole I drilled. I then completed connections to instrument lamps, power, ground.
With everything connected, I test-fitted the pillar pod and adjusted the guages rotation in the hole to my satisfaction. I removed the pod and installed the mounting clamps. I installed the pod.
Then I used Avery transparent mailing labels to print the graphics for the LEDs. I played with font, border, etc until I had the best compromise. If you can print on a laser printer, the grahics will be pretty sturdy. I only had inkjet, so I took a 2nd clear label and "laminated" over my printed label, then carefully cut the 2-label stack to size using a straightedge and xacto knife.
I got the knob handles at RatShack, I think.
Holy crap. Did I really waste my time doing all that? For the same effort, I could have installed enough mods to be in the 11's
I dunno, having read back over this, if it is worth the trouble. I did it over the course of 6 months or so, a few hours here and there. This kind of electrical prototyping was part of my job back in my radar-detector-industry days. I guess It didn't seem that unreasonable compared to some of the stuff I did back then.
Anyway, I wanted you to know what you were getting into. If you want to do it, I'll stand by with sage advice and sympathy.
Multi-input guages with dimmer circuit (long)
OK, here's a brain dump. Parts list for one guage (4 inputs):
all resistors can be cheapo 1/8 watt, RatShack
100 ohm
70 ohm
250 ohm
330 ohm
430 ohm (I used a 330 + 100)
a 3.2 V zener diode
a NTE 253 (or equiv) NPN Darlington pair transistor
two general purpose diodes
a 2 pole 4 throw rotary switch
two HP HLMP 2835 LED bar indicators
I got everything at allied electronics: www.alliedelect.com
Schematic (sorry, lost electronic original, this is the one I used and marked up during my assy and debug):
I suggest you get an extra LED bar unit for each guage. I ruined 2 before I got my technique perfected for this next part:
The HP LED bars come with each LED (4 per bar) pinned out seperately. You must wire them in series per this schematic close-up:
This is a pain in the butt. The right way would be to etch a little circuit board to do this, then solder the LED unit to the circuit board. I figured it would be easier to just hand-wire it using ultra-fine guage wire. Now I'm not so sure. I ended up doing it under a magnifying glass, with tweezers and the daintiest soldering pencil I could find. I still ruined 2 units (by overheating the pin, probably) before I got 4 good units wired. I made each connection as close to the backside of the LED unit as possible, then trimmed the LED pins short so the finished unit will be nearly flush against the guage glass.
After wiring and testing the LED bars, I super-glued 2 together to make a stack of 4 bars. I painted them flat black (except around the LED lenses).
I soldered the grounds from each bar segment together, and soldered on one long ultra thin power wire per bar, plus one ground wire for the whole stack. So, the finished stack of 4 bars now has 5 long (6 inches or so) fine wires extending out. all these wires must exit at the bottom of the stack, as closely together as possible. I tested the units again. A 9v square battery makes a perfect test supply for a single bar (4 diodes in series).
I assembled the dimmer circuit on vector board, packing everything in pretty tight (the board for each dimmer is about 3/4 inches by 3/4 inches). For each connection in/out of the dimmer (12v, ground, guage lamps, and output to switch), I added a length of fine wire and left it dangling. I wrapped the finished, tested dimmer in electrical tape to prevent shorting. At this point, it is a 3/4 inch cube with 4 wires dangling.
I set the bar stack into the face of the guage, and marked the inside edge of the bezel at the LED wire bundle. I then carefully lined up a dremel-style bit (maybe 1/32) so to drill a hole from the back edge of the bezel (where the bezel is swaged over the guage housing) out to the front inside edge of the bezel where I had marked it. I drilled 3 holes side by side then used an awl and jeweler's file to form a slot from the 3 holes.
I then loosened the movement from the housing (nuts on back of the guage), got the movement as far to one side as possible, and vacuumed out the drill flakes using a keyboard vac with shrink tubing as an extension, thru the hole for the light bulb.
I then fed the LED unit wires thru the bezel slot, from front to back. There is a rubber gasket in there that hinders this process. Stripping and solder-tinning an inch of wire makes them stiffer and helps them poke thru the gasket.
with the wires fed thru, I then test fit the guage in the pod (not pushing it in all the way) and mark where the wires will want to go thru the pod. I removed the guage and carefully filed a slot in the pod plastic to allow the wires to pass thru alongside the guage body when it is installed in the pod.
I then test-fitted the empty pod to the pillar, and marked a spot where the switch will extend vertically down. I drilled the holes for the rotary switch.
I attached the LED bar stack to the guage face, using a dab of silicone caulk. I carefully positioned it so it would be level with the guage graphics, and set a weight on it during the caulk cure. I touched up the flat black paint, and added a tiny filler panel (sheet styro-plastic from a hobby shop, painted black) to fill in between the flat bottom of the LED stack and the curved inside edge of the bezel. I attached the filler panel with a tiny dab of caulk.
I installed the guage in the pod, then soldered the LED wires to the switch contacts. I soldered light guage wire to the guage sender contacts on the switch.
In fact, I used the multi-conductor comm wire from which I got my LED wires. This makes a tidy bundle for the 8 wires going out to various senders. I terminated the light guage wires in the driver side fender, beside the wiper washer reservoir. I put in-line connectors to 14 guage wire, and ran the 14 guage wire to the senders.
Back to the guage. With all wires soldered to the switch, I connected the switch output to the guage input, then mounted the switch in the hole I drilled. I then completed connections to instrument lamps, power, ground.
With everything connected, I test-fitted the pillar pod and adjusted the guages rotation in the hole to my satisfaction. I removed the pod and installed the mounting clamps. I installed the pod.
Then I used Avery transparent mailing labels to print the graphics for the LEDs. I played with font, border, etc until I had the best compromise. If you can print on a laser printer, the grahics will be pretty sturdy. I only had inkjet, so I took a 2nd clear label and "laminated" over my printed label, then carefully cut the 2-label stack to size using a straightedge and xacto knife.
I got the knob handles at RatShack, I think.
Holy crap. Did I really waste my time doing all that? For the same effort, I could have installed enough mods to be in the 11's
I dunno, having read back over this, if it is worth the trouble. I did it over the course of 6 months or so, a few hours here and there. This kind of electrical prototyping was part of my job back in my radar-detector-industry days. I guess It didn't seem that unreasonable compared to some of the stuff I did back then.
Anyway, I wanted you to know what you were getting into. If you want to do it, I'll stand by with sage advice and sympathy.
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