RC Lights

Electronics

Radio Controlled Lights

This module is designed to switch on/off a set of Ultra Bright LEDs suitable for a model helicopter by using a spare channel on the receiver (usually the undercarriage toggle switch). The power is supplied by the RC receiver (5.2v if you use a higher voltage you will have to limit it to 5.5v for the PIC) the current doesn't exceed 100mA, around 20mA when off.

The LEDs were a problem, the ones I used are made by Kingbright needed 4v forward voltage except the Red ones which need 2.5v - so I used a limiting resistor to restrict the current.

The circuit is a constant current source, published in the Elektor Magazine (July/August 2010 page 45), controlled by an output from the PIC, I have modified it to allow 5 LEDs to be used from a 5.2v source.

Component List

PIC16F628
BC547B NPN Transistor
ZVN4306A MOSFET N
47k resistor
6ohm resistor
39k resistor
Red,Green,White Ultrabright LEDs
Servo lead
ABS Box
Strip Board

The internal oscillator is used in the PIC hence no external oscillator is needed.

Constant current = 0.6v/R2

Basic Program written in the Proton Basic Language.

'****************************************************************
* Name : RC-Lights.BAS *
* Author : *
* Notice : Copyright (c) 2010 Mr D.Murrell *
* : All Rights Reserved *
* Date : 04/08/2010 *
* Version : 1.0 *
* Notes : Internal oscillator 4Mhz, input = PortB.0 *
* : output = PortB.4 *
****************************************************************
Device 16F628
REMINDERS = off
Config INTRC_OSC_NOCLKOUT, CP_OFF, WDT_OFF, MCLRE_OFF, LVP_OFF, PWRTE_ON, DATA_CP_OFF, BODEN_ON
REMINDERS = On
XTAL = 4
WATCHDOG = false
ALL_DIGITAL = True
PORTB_PULLUPS = On ' Enable PortB pull-up resistors
Setup:
Dim RCPulse As Byte, Temp As Byte
Declare RSOUT_PIN PORTA.1
TRISB=0 ;PortB=outputs, Pulsein changes state of pin.0 to input
DelayMS 500
Main:
RCPulse = Pulsein PORTB.0, High
If RCPulse >170 Then
PORTB.4 = 1
Else
PORTB.4 = 0
EndIf
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