djpark
Enlightened
Edit: This thread started with the original Subject line "Arc-AAA-Lux Multi Brightness Multi Feature" to introduce the Arc-AAA head modded with a Luxeon and POP (PIC-O-PWM) driver. Now it is turned to a gallery of lights modded with the POP driver. The subject line is changed to reflect it.
Edit: New version of POP driver is made with more features. There is new post below.
Edit: DIY Kit soldering instruction and usage instruction video is added at later post.
I have tasted the sweetness of using PIC micro-processors to control the brightness and provide more features to the lights during H&M Contest 2004, and it rewarded me with well.
Class 2: Arc-AA 8mm ISP + Micro-P Multi Brightness
Class 4: Pager Light with 6 * 100mA LED & micro-P
Since then, I made a few more pills with 8mm led. But I have been always wanting to use the similar logic to control a Luxeon led for Arc-AA or AAA. So at last I got this done.
Arc-AAA-Luxeon-POPL with Multi-brightness, Multi-feature using PIC Mirco-Processor
- Using AAA size li-ion erchargeable battery (300mAh)
- High (300mA) and low (50mA) brightness levels using PWM
- Constant current regulation
- Turn on to last used brightness level
- Survival mode with super low current (15mA)
- Strobe mode and SOS mode
Changing brightness level is done by turning on the light, turn off within 1 second and turn on again. Current regulation is done using TPS73101 and I owe this knowledge to Doug_S.
Survival mode is not on PWM, but direct output from PIC io pin.
5th turning on triggers survival mode (dim mode). 6th turning on triggers strobe mode (5 Hz) and 7th turning on triggers SOS mode.
Head construction
I used a blank (no HA) Arc-AAA head acquired long ago and ground the front section deeper to U-shape to make it a better reflector. It is not perfect since I had to work with hand tools only, but reasonable after polishing.
I added a little epoxy to top part of the plastic led holder along the side of the dome. This strengthens the bonding of the dome to led so that it will not drop out. It also seals the dome, so it can be exposed to the environment without using a lens or optic to cover. A bit of GID powder was mixed in the epoxy, so it gives slight hint of blue-green when the light is off.
I cut a small piece of aluminum sheet to a round shape as the heatsink. It is made to be very tight fit within the Arc-AAA head cavity. I don't have thermal epoxy, so I mixed Arctic Silver 5 with Devcon 5 minutes epoxy and applied between the Luxeon slug and the heatsink. Then it is inserted in to the head with some force. Then a little more epoxy was added at the back of the heatsink to fix it to the wall. It appears to be quite acceptable. When I turn on the light on high level, the head gets warm pretty fast, but not too hot at 300mA. 700mA made the head quite hot.
The controller board has only 3 SMT parts -- PIC12F675, TPS73101 and 0.1uF capacitor. They are put on the original Arc board after stripping all parts and pcb traces. Without having a facility for pcb making, I had to resort to 3D soldering and also have to skip the reverse battery protection as used by Doug_S.
Crimp back, then the new head is ready.
Beamshots
The Luxeon I use is taken out from Arc-LSH-P and it gives very nice warm tint and I like it. I paid a big buck to get this warm tint.
Due to the poor reflector I made, the hot spot is smaller than 17mm IMS reflector and more to the flood. But it still has a small hot spot in the center and the it is quite well focused. Not just flat flood output.
The following pictures are taken with the light on the floor and 50cm away from the wall. High and low brightness with different camera setting. f2.8 2 seconds exposure gives me the picture closest perception to my eye adjusted to the darkness.
Ceiling 3m away.
To compare the brightness of survival mode.
Not to forget the strobe and SOS mode.
Run time
This run time chart of the light running on High brightness level. The low brightness level is on logging now and it is still showing no sign of brightness change after 2 hours.
The brightness went up a little during the initial 2 minutes. Then it stayed very flat till 45 minutes when the battery nearly got used up. The sun mode is followed by 15 minutes of gradual dropping moon mode plus long period of star mode.
Considering the battery capacity 300mAh and the current draw 300mA, this run time seems very acceptable.
One thing good about the LDO regulation of li-ion cell is that it never bring the battery voltage below 2.5V with white led since the current will simply drop when the voltage drops. So the over-discharge protection is not necessary.
Here is a logging done with 14500 (AA) li-ion battery, measured battery voltage, current draw and the relative brightness.
The battery was charged during H&M Contest, that means about 6 months in storage. Then it still gave more than 600mAh worth discharge from 700mAh battery capacity.
The battery voltage dropped below 4V immediately, then gradually dropped to 3.2V next 110 minutes. During this period, the brightness and the current flow is very flat. It started showing sign of going off current regulation at 3.2V. Then 15 minutes of moon mode followed by many hours of star mode.
It indicates that the Vf of the Luxeon taken out of LSH-P is very low and the current limit of TPS73101 is very stable.
I will add run time chart of low brightness level when the logging is complete.
Enjoy!
-- dj
Edit: The current values were changed according to the actual measurement.
Edit: New version of POP driver is made with more features. There is new post below.
Edit: DIY Kit soldering instruction and usage instruction video is added at later post.
I have tasted the sweetness of using PIC micro-processors to control the brightness and provide more features to the lights during H&M Contest 2004, and it rewarded me with well.
Class 2: Arc-AA 8mm ISP + Micro-P Multi Brightness
Class 4: Pager Light with 6 * 100mA LED & micro-P
Since then, I made a few more pills with 8mm led. But I have been always wanting to use the similar logic to control a Luxeon led for Arc-AA or AAA. So at last I got this done.
Arc-AAA-Luxeon-POPL with Multi-brightness, Multi-feature using PIC Mirco-Processor
- Using AAA size li-ion erchargeable battery (300mAh)
- High (300mA) and low (50mA) brightness levels using PWM
- Constant current regulation
- Turn on to last used brightness level
- Survival mode with super low current (15mA)
- Strobe mode and SOS mode
Changing brightness level is done by turning on the light, turn off within 1 second and turn on again. Current regulation is done using TPS73101 and I owe this knowledge to Doug_S.
Survival mode is not on PWM, but direct output from PIC io pin.
5th turning on triggers survival mode (dim mode). 6th turning on triggers strobe mode (5 Hz) and 7th turning on triggers SOS mode.
Head construction
I used a blank (no HA) Arc-AAA head acquired long ago and ground the front section deeper to U-shape to make it a better reflector. It is not perfect since I had to work with hand tools only, but reasonable after polishing.
I added a little epoxy to top part of the plastic led holder along the side of the dome. This strengthens the bonding of the dome to led so that it will not drop out. It also seals the dome, so it can be exposed to the environment without using a lens or optic to cover. A bit of GID powder was mixed in the epoxy, so it gives slight hint of blue-green when the light is off.
I cut a small piece of aluminum sheet to a round shape as the heatsink. It is made to be very tight fit within the Arc-AAA head cavity. I don't have thermal epoxy, so I mixed Arctic Silver 5 with Devcon 5 minutes epoxy and applied between the Luxeon slug and the heatsink. Then it is inserted in to the head with some force. Then a little more epoxy was added at the back of the heatsink to fix it to the wall. It appears to be quite acceptable. When I turn on the light on high level, the head gets warm pretty fast, but not too hot at 300mA. 700mA made the head quite hot.
The controller board has only 3 SMT parts -- PIC12F675, TPS73101 and 0.1uF capacitor. They are put on the original Arc board after stripping all parts and pcb traces. Without having a facility for pcb making, I had to resort to 3D soldering and also have to skip the reverse battery protection as used by Doug_S.
Crimp back, then the new head is ready.
Beamshots
The Luxeon I use is taken out from Arc-LSH-P and it gives very nice warm tint and I like it. I paid a big buck to get this warm tint.
Due to the poor reflector I made, the hot spot is smaller than 17mm IMS reflector and more to the flood. But it still has a small hot spot in the center and the it is quite well focused. Not just flat flood output.
The following pictures are taken with the light on the floor and 50cm away from the wall. High and low brightness with different camera setting. f2.8 2 seconds exposure gives me the picture closest perception to my eye adjusted to the darkness.
Ceiling 3m away.
To compare the brightness of survival mode.
Not to forget the strobe and SOS mode.
Run time
This run time chart of the light running on High brightness level. The low brightness level is on logging now and it is still showing no sign of brightness change after 2 hours.
The brightness went up a little during the initial 2 minutes. Then it stayed very flat till 45 minutes when the battery nearly got used up. The sun mode is followed by 15 minutes of gradual dropping moon mode plus long period of star mode.
Considering the battery capacity 300mAh and the current draw 300mA, this run time seems very acceptable.
One thing good about the LDO regulation of li-ion cell is that it never bring the battery voltage below 2.5V with white led since the current will simply drop when the voltage drops. So the over-discharge protection is not necessary.
Here is a logging done with 14500 (AA) li-ion battery, measured battery voltage, current draw and the relative brightness.
The battery was charged during H&M Contest, that means about 6 months in storage. Then it still gave more than 600mAh worth discharge from 700mAh battery capacity.
The battery voltage dropped below 4V immediately, then gradually dropped to 3.2V next 110 minutes. During this period, the brightness and the current flow is very flat. It started showing sign of going off current regulation at 3.2V. Then 15 minutes of moon mode followed by many hours of star mode.
It indicates that the Vf of the Luxeon taken out of LSH-P is very low and the current limit of TPS73101 is very stable.
I will add run time chart of low brightness level when the logging is complete.
Enjoy!
-- dj
Edit: The current values were changed according to the actual measurement.
