Ron3KL
08-29-2002, 12:22 AM
My 10 year old son is an avid reader and does not appear to be prone to car sickness. So he likes to read when we travel, using one of the rear reading lamps at night.
In our old 850 that wasn't a problem because the reading lamps were off to the side near the passenger grab handles. However, in the XC the lamps are located in the center so that they do not interfere with the inflation of the air curtain. The downside of this is that when the lamps are on there is a lot of reflection in the driver's mirror.
Thinking about this problem I realised that we could make use of two innovations
1) the 12V outlet in the cargo compartment, and;
2) recently developed high intensity LED technology.
My son and I built a small reading lamp that uses a super-white LED with a light output of 6000 mcd (standard LED's outputs range from 5 - 500 mcd). It is contained in a small box that is stuck to the headlining with hook and loop tape. We have positioned it above his lap for reading but away from the air curtain for safety.
The advantage of using a LED over a standard bulb is that it has a very narrow beam which is barely visible in the driver's mirror. It also has a very low current draw; so low in fact that the ECU does not detect that the 12V socket is in use. This means that the normal dashboard warning message you get when the socket is in use is not displayed. Accidently leaving the light on is not a problem either.
We worked on the design together and designed the gadget to use either the 12V car supply or a built in 9V battery. This means it doubles as a pocket torch. We also decided to include a dimmer. I did the mechanical bits like drilling and cutting, but he did most of the soldering and assembly, which just goes to show that it is a suitable project for a youngster interested in basic electronics.
The following photos show:
# 1 - The cicuit diagram, including the dual voltage supply and dimmer. It could be made a lot simpler by deleting the 9V battery, the switch/socket and dimmer.
# 2 - The parts we used.
# 3 - Picture of the simple circuit board.
# 4 - Picture of the inside of the completed gadget.
# 5 - The lamp in position in the car.
In our old 850 that wasn't a problem because the reading lamps were off to the side near the passenger grab handles. However, in the XC the lamps are located in the center so that they do not interfere with the inflation of the air curtain. The downside of this is that when the lamps are on there is a lot of reflection in the driver's mirror.
Thinking about this problem I realised that we could make use of two innovations
1) the 12V outlet in the cargo compartment, and;
2) recently developed high intensity LED technology.
My son and I built a small reading lamp that uses a super-white LED with a light output of 6000 mcd (standard LED's outputs range from 5 - 500 mcd). It is contained in a small box that is stuck to the headlining with hook and loop tape. We have positioned it above his lap for reading but away from the air curtain for safety.
The advantage of using a LED over a standard bulb is that it has a very narrow beam which is barely visible in the driver's mirror. It also has a very low current draw; so low in fact that the ECU does not detect that the 12V socket is in use. This means that the normal dashboard warning message you get when the socket is in use is not displayed. Accidently leaving the light on is not a problem either.
We worked on the design together and designed the gadget to use either the 12V car supply or a built in 9V battery. This means it doubles as a pocket torch. We also decided to include a dimmer. I did the mechanical bits like drilling and cutting, but he did most of the soldering and assembly, which just goes to show that it is a suitable project for a youngster interested in basic electronics.
The following photos show:
# 1 - The cicuit diagram, including the dual voltage supply and dimmer. It could be made a lot simpler by deleting the 9V battery, the switch/socket and dimmer.
# 2 - The parts we used.
# 3 - Picture of the simple circuit board.
# 4 - Picture of the inside of the completed gadget.
# 5 - The lamp in position in the car.