Front hull with embedded head light by Oger

Last crawled date: 2 years, 11 months ago

This is a remix of the file " Chassis_2_V1" for Staind's RC Tank.
I wanted to add some headlights and I found a cool looking USB bike light for about 6 Euro on Ebay. It is somewhat oversized, but I like this asymmetrical "hull mounted laser gun" look of the light embedded in the hull.
The light is held in place by a M3x5 screw, which is a bit of a hassle to unscrew. I recommend removing the right motor, to avoid breaking your fingers. ;-)
The next step is to replace the LED driver which requires to push a little button on the back plate of the light to switch it on and off. A constant current driver operating from 6 V to 15 V should do nicely for powering it directly from the main battery and to add an RC switch to control the light by the transmitter.
I printed the chassis without supports using PETG and lots of cooling.
Here is the url of the light:
http://www.ebay.de/itm/MINI-USB-5000lm-XML-T6-LED-Fahrradlampe-Licht-Fahrradbeleuchtung-Fahrradlicht/142130574338?ssPageName=STRK%3AMEBIDX%3AIT&var=441208015357&_trksid=p2060353.m2749.l2649
The same light is also available from AliExpress. The size is 28 mm x 28 mm.
Edit:
2017-12-16
Added a back cover for the USB bike light.
It uses the screws from the original back cover of the light and it has an opening for the wires to the PCB which drives the LED. The PCB is glued into place in the ring on the inner side of the cover plate.
2017-10-18
Made some measurements of the lights current draw and power consumption:
Input 5V from USB Power Bank
LED current:
mode 1: 0,3 A
mode 2: 0,6 A
mode 3: 1,15 A
So when powered from a USB source, the LED runs with a forward current up to 1,15 A. I personally would aim for something between 0,75 A and 1 A. Just to be sure. The difference in brightness is not really that great.
After removing the build in driver and control board with the bothersome 3 mode switch (which prevents the light from being controlled via an RC switch) I coupled the LED with this constant current LED driver:
http://www.dx.com/de/p/3-6v-9v-800ma-regulated-ic-circuit-board-for-cree-and-ssc-leds-4-pack-3256#.Weee2DtpGpp
It says the output is 925 mA constant current, but like with all cheap Chinese circuit boards the actual value might be somewhat different:
Input voltage | input current | Power Consumption | LED Current
4,5 V | 0,59 A | 2,6 W | 0,78 A
5,5 V | 0,48 A | 2,68 W | 0,78 A
6,5 V | 0,42 A | 2,7 W | 0,78 A
8 V | 0,4 A | 2,73 W | 0,77 A
9 V | 0,3 A | 2,9 W | 0,8 A
9,5 V | 0,43 A | 4,14 W | 1,1 A
10 V | 0,51 A | 5 W | 1,28 A
So between about 4 V to about 9 V input voltage the driver gives a reliably stable constant current of about 0,8 A which I consider a good trade off between brightness, power consumption and heat generation -> long-time safety for the LED. Perfect for powering the driver with a 2S LiPo.
I would not recommend running the LED with 1,28 A @ 10 V input voltage, as it might reduce the LEDs lifespan.