How to dim your remote LED on your ALP system

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09-16-2014, 06:39 PM
dukes

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How to dim your remote LED on your ALP system

Seen many ask about dimming their remote LED so I thought I would make a how to guide. This will obviously void your warranty on your remote LED, but the remote LED can be purchased from BRD.

I used this controller I purchased off Ebay for 2$. http://www.ebay.ca/itm/12-24V-Mini-I...f683b86&_uhb=1

Attachment 2579

Note there are 6 wires. When I cut the LED cable, I gave my self plenty of room in case I messed up.

On the LED controller you will note that one side says "+LED-" and the other says "+12v-". Black wires are ground and red are positive.

Connect the YELLOW wire to the controller's positive cables. Note that it must correspond to the controllers "+LED-" and "+12v-". So obviously the cut cable with the rj11 on the end goes to the "+12v-" and the cut end with the LED to the "+LED-"

Connect the BLUE wire to the controller's negative cables. Note that it must correspond to the controllers "+LED-" and "+12v-". So obviously the cut cable with the rj11 on the end goes to the "+12v-" and the cut end with the LED to the "+LED-"

After that, solder your connections and shrink wrap it up nicely

You are now all done!

You'll notice that the only LED color that is dimmer is the blue one. The rest are still the normal brightness. Which is nice since the blue is constant.

https://www.youtube.com/watch?v=EBHY...ature=youtu.be
09-16-2014, 07:19 PM
icepick

Nice writeup!

I wish AL would have thought of this, the confidence LED is far too bright and dimming it by any other means than what you have designed makes the alert intensity insufficient. Dark mode just makes me wonder... did I lose power?

Great solution!
09-16-2014, 11:11 PM
BestRadarDetectors

Before others jump on board and try this please wait till AL gets a chance to look at this to make sure there is no back-feed or any other possible issues which could lead to a future CPU issue.
09-17-2014, 06:51 AM
radargeek

A simpler way that won't lead to back-feeding is to simply add a resistor in series with the wire(s) for the LED color(s) you want to dim. You might have to experiment with different resistances to get the desired brightness, but a 470 ohm to 1K resistor would probably work well. Go higher for dimmer, or lower for brighter. It's simpler, cheaper, and safer for the CPU (I don't trust those cheap Chinese ebay electronics), plus you can dim more than one color if you like.

If you don't want to cut up the wires to your LED, a compatible modular plug and jack could be used with the resistor(s) wired in between, and then just plug that in between the CPU and the LED.

Perhaps a future firmware update can allow a settable brightness for the LEDs, since the CPU or control set could just PWM them to change the brightness. Or take a page from the V1, Redline, and STi-R+ and add a light sensor to the control set and have the LEDs auto-dim.
09-17-2014, 07:24 AM
BestRadarDetectors

Quote:

Originally Posted by radargeek

A simpler way that won't lead to back-feeding is to simply add a resistor in series with the wire(s) for the LED color(s) you want to dim. You might have to experiment with different resistances to get the desired brightness, but a 470 ohm to 1K resistor would probably work well. Go higher for dimmer, or lower for brighter. It's simpler, cheaper, and safer for the CPU (I don't trust those cheap Chinese ebay electronics), plus you can dim more than one color if you like.

If you don't want to cut up the wires to your LED, a compatible modular plug and jack could be used with the resistor(s) wired in between, and then just plug that in between the CPU and the LED.

Perhaps a future firmware update can allow a settable brightness for the LEDs, since the CPU or control set could just PWM them to change the brightness. Or take a page from the V1, Redline, and STi-R+ and add a light sensor to the control set and have the LEDs auto-dim.

You can bet we are always looking for ways to make the ALP better but many things would require hardware changes.

When they improved the connectors on the sensors we had months of complaining from users with the old connectors.

If we introduced new CPU's with enhansed capability to dim the LED's I am sure we would again hear complaints from early adopters.

Technology does improve and eventually we will have to improve hardware but we will try to find mods like this for those with old hardware.

I will discuss with engineering a safe way to dim the External LED for those concerned with its brightness and one which would not void your warranty.
09-17-2014, 07:47 AM
radargeek

I wouldn't think making the LEDs dimmable would require a hardware change. Just code the firmware to PWM the LEDs at a high rate. Both the CPU and control set have updatable firmware, so I would think it's doable, unless there's some hardware limitation preventing it.
09-17-2014, 07:54 AM
BestRadarDetectors

Quote:

Originally Posted by radargeek

I wouldn't think making the LEDs dimmable would require a hardware change. Just code the firmware to PWM the LEDs at a high rate. Both the CPU and control set have updatable firmware, so I would think it's doable, unless there's some hardware limitation preventing it.

The hardware has no regulators to change the resistance or voltage of the LED's. A simple change like this would require a hardware modifications. Is it a big enough deal to warrant the complaints? I dont think so. There are now 6 different LED configurations available and there are plenty of easy and safe ways reduce the brightness if its that much of an issue. Heck the competition LI, LSP & HP-905's dont even have a status LED that shows when the system is activated and Jamming let alone tell you the direction from a single LED.

Just get one of these.....

https://www.youtube.com/watch?v=6TZ7uS93mSo#t=24
09-17-2014, 08:11 AM
Mirage

Quote:

Originally Posted by BestRadarDetectors

https://www.youtube.com/watch?v=6TZ7uS93mSo#t=24

I was going to mention these... a permanent marker works good too! That's what K40 users use! :rolf:
09-17-2014, 08:21 AM
radargeek

Quote:

Originally Posted by BestRadarDetectors

The hardware has no regulators to change the resistance or voltage of the LED's. A simple change like this would require a hardware modification.

Pulse width modulation (PWM) can be done entirely in software; it's just turning the LED on and off at a high rate of speed so to the eye it looks like it's constantly on and by changing the duty cycle (% of time on vs. off), the brightness of the LED can be changed entirely in software.

Just about everything uses PWM now, from the backlight in your smartphone screen to the display in your RD, and even the lights in your car. Unless there's some limitation in the ALP CPU's design in how it addresses the LEDs, it should be simple to implement in firmware.

A Sharpie works too. :)
09-17-2014, 08:25 AM
Mirage

Quote:

Originally Posted by radargeek

Pulse width modulation (PWM) can be done entirely in software; it's just turning the LED on and off at a high rate of speed so to the eye it looks like it's constantly on and by changing the duty cycle (% of time on vs. off), the brightness of the LED can be changed entirely in software.

Just about everything uses PWM now, from the backlight in your smartphone screen to the display in your RD, and even the lights in your car. Unless there's some limitation in the ALP CPU's design in how it addresses the LEDs, it should be simple to implement in firmware.

I agree PWM is simple and should be easy to implement, but how much effort do you want AL putting into dimming a LED vs working on other add-ons. I personally don't want anything to detour the Android ALP Connect. I'm telling you light dims or a permanent marker work great and won't void your warranty if you mess something up!
09-17-2014, 10:07 AM
awj223

Quote:

Originally Posted by icepick

Nice writeup!

I wish AL would have thought of this, the confidence LED is far too bright and dimming it by any other means than what you have designed makes the alert intensity insufficient. Dark mode just makes me wonder... did I lose power?

Great solution!

I don't know, the only thing a constant LED tells me is that the system is powered up. But it doesn't tell me that the CPU is still running. Assuming that the blinking LED is controlled by some process on the CPU, the blinking action to me indicates that the CPU is actually doing something (the watchdog timer is firing, the CPU is switching the LED on, and then off). But a constant LED? Well if the CPU were to hang, wouldn't the LED simply remain on? Knowing that the system has power is not the same as knowing it's running. That's why I'm probably just going to keep on using dark mode. If I want to confirm it's running, I'll hit a button and make sure it responds.
09-17-2014, 10:36 AM
radargeek

Quote:

Originally Posted by awj223

I don't know, the only thing a constant LED tells me is that the system is powered up. But it doesn't tell me that the CPU is still running. Assuming that the blinking LED is controlled by some process on the CPU, the blinking action to me indicates that the CPU is actually doing something (the watchdog timer is firing, the CPU is switching the LED on, and then off). But a constant LED? Well if the CPU were to hang, wouldn't the LED simply remain on? Knowing that the system has power is not the same as knowing it's running. That's why I'm probably just going to keep on using dark mode. If I want to confirm it's running, I'll hit a button and make sure it responds.

If the LED is dimmed via PWM it's essentially blinking at a fast rate (faster than the eye can see), so if the CPU were to hang, and software PWM is used, the LED would either get stuck on full brightness or off.

That's not a 100% reliable indication of system stability, however. Depending on the nature of the failure the PWM loop could still be running but other functions stop working, or vice versa. Or PWM may be implemented in hardware or in a CPU peripheral that keeps working even if the main CPU hangs. A good design uses a watchdog timer to reset the CPU if it hangs (another feature built into most microcontrollers).

Pressing a button is a better way to know "for certain" that the system is functioning correctly.