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This page was last updated on: 10/28/10.
Specifications for the Hahntronix Bike Light User Interface
All Hahntronix bike lights use high intensity LEDs driven by a current controlled buck converter. The buck converter is controlled by a small 8 pin microcontroller. Software programmed into the microcontroller determines the user interface for the light and handles tasks such as warning the user when the the battery is getting low, and dimming the light if it becomes too hot.
The user interface:
At first glance, it seems sort of obvious. There is a button on the back. As expected, you push it to turn on the light. About 1/4 of a second after you push the button, the light will turn on at a low power level. When you release the button, the light will switch to it's last remembered mode. The initial 1/4 second press helps keep the light from turning on accidently.
You can think of the light as having three states: light, flasher, and off. Each of the states have modes. You switch between states and modes using different length button presses.
The light responds to two kinds of button presses: push, and hold.
A push is a short press of the button from around 1/10th to 1 second. The lower number is done to prevent the light from banging against something and switching modes accidently. A push switches the light between modes. The light will change what it is doing after you release the button.
A hold of the button is a press that lasts for more than 3 seconds and less than 15. If you hold the button down for more than 3 seconds, the light will change states. The normal change that happens is if the light is on and you hold the button for longer than 3 seconds, it will turn off. You can change between light and flasher states by continuing to hold the button down. For example if you are using the light as as an always on headlight and you wish to switch it to be a flasher, hold the button down for 3 seconds and the light will turn off. Hold the button for 3 more seconds and the light will begin to flash.
When your light is in the light state a push of the button will switch the light to the next light mode or level. The light is factory set to have 3 light levels: high, medium, and low. High is 100% power. Medium is 66% power. Low is 33% power.
Why use different levels? One reason to use a lower level than high when climbing, or riding slowly, is it will conserve battery power. If you run your light at the medium level all the time, your battery will last 1.5 times as long as it would if you had the light on high. If you run your light at the low level all the time, your battery will last 3 times as long.
You can set the brightness levels for low and medium. I'll cover that in the programming appendix. You can also change the number of levels to be just 2, so you don't have to cycle through as many. This might be handy if using the light when racing. A racer might be interested in having a low level that allowed her to see the trail when racers in front of her had churned up a lot of dust, but she would run the light on high the rest of the race to allow her to ride at the fastest speed.
The flasher has 4 modes or patterns: beacon, flash, blink, and hi-lo.
Beacon is 3 quick bursts of light, followed by about 2/3 of a second of no light. It looks very much like the flash pattern you see on tow trucks or emergency services vehicles. I've had people stop me and say they thought I was some kind of police vehicle when I've been running this flasher pattern. Which is just fine with me. When the flasher mode gets traffic's attention, they often slow down. Beacon runs the LEDs for about 25% of the time. If your battery would normally last 2 hours with your light on high, it will last 8 hours in the beacon mode.
Flash is a simple on, off, on, off, etc. kind of flash. It flashes about twice a second. It gets folks attention, but is a bit less intimidating than the emergency beacon. Flash runs the LEDs about 50% of the time. If your battery would normally last 2 hours with your light on high, it will last 4 hours in the flash mode.
Blink runs the LEDs on for most of the time. About once a second, it will switch to a dim level for less than 1/10th of a second. The overall effect is kind of subtle. I like to use this mode on my headlight when road riding near dawn or dusk, when it's nice to have a bit of light to see by. The 1/10th of a second blink gets oncoming drivers attention. This mode is equivalent to running the LED about 95% of the time.
Hi-Lo runs the LED through a high-low pattern about twice a second. It looks very much like a motorcycle headlight that has a headlight modulator. It's good for daylight running. It's pretty noticeable to oncoming traffic when run on your headlight. On a tail-light it is very noticeable in bright sunlight.
All of the flasher patterns use the last light mode level to set the maximum output of the LED. For example, if the last light level was medium, the Hi part of a Hi-Lo flash would be about as bright as the headlight is when it's run at medium. The Lo part will be pretty dim.
Why does the flasher state use the last state brightness level? It allows you to make the flasher brighter or dimmer as needed. By running the flasher at a lower brightness, you will greatly extend your battery run time. The ability to adjust the flasher brightness levels is very handy in the BRL-2010 tail-light when riding in a group. Turn the level down to avoid blinding riders right behind you. If using a tail-light, you will typically not need as much light to be visible on a dark country road as you would need in city traffic.
Off basically turns the LED off. It also remembers the last way you had the light set up when you turned it off. When you turn the light on again, it will remember the last mode it was set to. The light also remembers how you have set it about 10 seconds after you change a mode or state. Sometimes when it does this you will notice the light dim for just a few hundredths of a second. The light remembers it's last setting like this in case you loose power, like if a tree branch rips your headlight cable loose, or if you have a bad connection somewhere between the light and your battery.
You enter off mode by holding the button down for about 2 seconds. The LEDs will turn off. Release the button. I decided to use a long press to turn the light off to prevent a rider from accidentally turning off the light.
You exit off mode by pressing the button for at least 1/4 of a second. The LEDs will come on at about half power. When you release the button the light will return to the last state and mode it was in before you turned it off. So for example if you were in the flasher state and turned the light off, when you turn it on again, it will be in the flasher state.
Some people have reported that earlier versions of the lights turned on when stored in their packs. The 1/4 second button press requirement will hopefully eliminate the chances of that happening. The best way to avoid having your light turn on unexpectedly in a backpack, is to unplug your battery before storing it there.
While your light is in the off state, it will continue to draw a very small amount power, typically something like 1/2 of a mA per hour. You could leave it plugged into a 2200 mAh battery pack for 2 weeks and drain less than 1/5th of the batteries capacity. If you are not using the light for a few hours, it's a good idea to unplug the batteries.
The user interface has a few features to let the user know if things aren't going well. It will warn you of intermittent connections and low battery voltage. It will also dimm the LED if the light becomes too hot.
When you plug the light into a battery, it will blink on and off very rapidly 3 times. If you notice this blink happening while you are riding, you should look for a loose connection between the battery and the headlight. If you plug the headlight in and it doesn't blink, it is possible the microcontroller failed to reset. This doesn't happen very often (I have only had it happen to me a couple of times and that was due to a misprogrammed microcontroller). Try unplugging the headlight, wait 10 seconds, then plug it back in. If trying this a few times fails to work, you may have a dead battery, a break in your power cable or a malfunctioning light.
The light's microcontroller measures and regulates the temperature of the LEDs to avoid frying them. LEDs are way more efficient at producing visible light than an incandescent bulb, but they don't radiate IR heat the way an incandescent does. Usually this is not a big issue when riding. A speed of 3 or 4 miles per hour usually provides enough air flow to keep the light's housing cool. If you stop to check a map or chat at an intersection, the LEDs may start to warm up. Eventually the microcontroller will detect that the LEDs are too hot. It will then automatically turn down the brightness. If the light continues to get hotter, the microcontrller will continue to turn down the brightness. Once you start riding again, the microcontroller will return your light to full brightness, but it may take a couple of minutes if the light has gotten very hot. You can avoid having the light take time to return to light level you want by turning down the light level when stopped or climbing a long hill.
The light's microcontroller measures battery voltage. It will flash the LED five times when the battery voltage gets below a warning level. For a 9.6 volt NiMh battery, it will start doing the warning flashes when the battery voltage gets down to around 8.5 volts. This is above the level that you should not run your NiMh batteries below (generally accepted as 1 volt per cell, or 8 volts for a 9.6 volt battery). It will flash the LEDs 5 times about every 30 seconds. If you switch the LED to a lower brightness level, this will sometimes stop the warning flashes for a little while, as the battery voltage will climb up from the warning level due to the reduced load. But you should still think about replacing your battery soon. In the appendix on programming the light we will discuss how to set the warning level for the type of battery you want to use with the light.
You can temporarily halt low voltage warning flashes simply by changing light level or flasher mode. Doing so will stop the warning flashes for about 10 minutes.
Appendix A: Hahntronix User Interface User Programming Options
The user interface behavior can be changed pretty easily for different types of riding. A road rider may want 3 light levels. A mountain bike racer may only want 2, low for riding through dust kicked up by other riders and high. Users may find the factory programmed low and medium light levels to be too dim or too bright for the conditions they are riding in. The user will also need to change the low battery warning level if switching to different voltage batteries.
To access the light's programming features, press the button and hold it like you would to turn the light off, but keep holding the button down. If you were in the light state, the light will turn off, it will enter the flasher state for about 5 seconds and will then turn off for another 5 seconds. Keep holding the button down. Eventually the light will begin to do a series of bright / dim flash patterns. Each pattern is repeated twice. There is a 1 second pause between flashes that make up the pair of flashes where the LEDs are off. Once this pair of flashes has started and during the 1 second break in between, if you release the button, you have selected to change a programmable option.
Between flash pairs, there will be a 3 second pause where the LEDs are off. You may release the button during that time to exit programming mode return to normal light operation.
3----------2 or 3 light levels
5----------set low brightness level
7----------set high brightness level
9--------- set battery warning level
2 or 3 light levels:
This option is a toggle. If your light cycles through 3 light levels and you release the button while it is cycling through the 3 blinks for this option, your light will now only do 2 light levels. With 3 light levels you cycle through high, low, medium, high, low, medium, etc. With 2 light levels you cycle through high, low, high, low.
Set low brightness level:
This option is allows you to select the light level used for the low headlight setting. As before, enter programming mode and wait for 2 sets of 5 flashes, releasing the button sometime during the flashes. The light will begin to ramp up in brightness, taking about 5 seconds to go from a very dim setting to full brightness. It will repeat this ramp 5 times. Just press the button to select the level the light is at any time during the ramp in brightness
Set medium brightness level:
This works exactly like setting the low level, except you need to wait for 7 flashes. Please note that you can set your medium brightness level to be dimmer than your low brightness level if you want to. That would make your 3 level light switch like: high, medium, low, high, etc.
Set the low battery warning level:
Enter programming as mentioned above, and wait for 9 flashes. If you start with a fresh set of batteries, the light will automatically figure out what warning level to use. About 2 seconds after you release the button, the light will flash a 3 digit value to indicate what the battery warning voltage level is set to. The value is flashed with 10 flashes representing 0, with leading 0s skipped. For example, the pattern 8 5 would represent a low warning voltage of 8.5 volts.
6 5 ... 6.5 volts, good for 7.4 volt LiIon battery or 7.2 volt NiMh battery
8 5 ... 8.5 volts, good for 9.6 volt NiMh battery
9 9 ... 9.9 volts, good for 11.1 volt LiIon battery or 12 volt NiMh battery
1 2 5 ... 12.5 volts, good for 14.8 volt LiIon battery or 14.4 volt NiMh battery
1 6 5 ... 16.5 volts, good for 18.5 volt LiIon battery or 19.2 volt NiMh battery
2 10 10 ... 20.0 volts, good for 22.2 volt LiIon battery or 24 volt NiMh battery
The above warning levels should cover most of the battery packs you'll find commercially available.
That's All Ffffolks!