The Thule Coaster XT bike trailer comes standard with two red reflectors at the back. There's no tail light. This project adds a LED array to the bike trailer. It serves as tail light and allows for showing warning messages.
Legrand DLP50X105mm, cut to 70cm length
End piece for cable tray
Televic LED array 7x80 LEDs
Available from Buda::lab
Christoph Tack •
03/27/2019 at 20:03 •
Powering the LED array
The LED array has the following power consumption:
The LED array seems as bright on 3V0 as on 3V9. 3V0 is really a minimum voltage. Lower voltages leave artefacts in the LED array.
Using buckboost module
The current draw from the LED array is simply too big for the AliExpress 32757272432 and the AliExpress 32892547111.
Using boost module followed by buck module
I used the HWA YEH SX1308 boost module and set it to 5V output. Somehow the IC got fried and I replaced it with a MPS MP3221. The buck module is the WAVGAT XM1584. It has been set to 3V3 output.
This solution works well for a few minutes, but then the components are getting hot and the modules repeatedly enter a thermal shutdown state.
This solution draws about 1.7A from a 3.3V power supply.
Using linear regulator
AP7363-33D-13 (IC REG LINEAR 3.3V 1.5A TO252)
Adding an MBRS240L schottky diode after the 3V3 output of the LDO reduces the voltage to the LED array to 2.96V. This reduces current consumption by about 500mA.
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