I have a flashlight that I would like to change what it does.
I want the blinking LED circuit(one bulb) to be used to run the 4 LEDS that are used for the "flashlight".
In other words, I would like the 4 LEDS to blink.
I don't care if the blinking LED is no longer available.
Here is the circuit.
Blinking LED circuit has positive going to one lead of the blinking bulb.
Other lead going to bulb has a resistor going between 2nd lead of blinking LED to one lead of the LED #4 that make up the 4 LEDS previously mentioned.
Can I wire it so that the 4 LEDS blink instead of the single LED?
Thanks, Andy
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T
Tim Wescott
Try posting a schematic of what you propose.
Tim Wescott
Wescott Design Services
http://www.wescottdesign.com
Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html
M
Mint
I don't have a schematic.
That's why I posted what the circuit board looks like and all it's connections.
Andy
E
ehsjr
Draw one in ascii. Make up understandable symbols as needed:
Resistor = ---[R]--- or ---/\/\/--- LED = ---[LED]--- Bulb = ---[Bulb]--- Blinking LED = ---[BlinkingLED]--- Battery = ---[+Batt]---
Show values where needed. For example ---[470R]--- is a
470 ohm resistor.
Ed
W
Winston
(...)
Or download Andreas Weber's excellent AACircuit program:
formatting link
--Winston
M
Mint
Thanks a lot Winston.
Andy
M
Mint
I will do that.
I will have to look up the value of my resistor.
Andy
M
Mint
DS
In making this, I realized that the blinking LED is not controlled by a circuit. It blinks when voltage is applied to it.
It looks like I would have to replace the 4 "regular" LEDs with the "blinking" type or a circuit to make those blink.
Andy
[LED1] [R1]
[LED4] [BlinkingLED5] [LED2]
[R2] [LED3]
Notes: LED5 emits red light [R1] =3D 20 ohms [R2] =3D 10 ohms + to one lead of all LEDS
Resistor =3D ---[R]--- LED =3D ---[LED]--- Bulb =3D ---[Bulb]--- Blinking LED =3D ---[BlinkingLED]--- Battery =3D ---[+Batt]---
J
John Fields
You have to show connections, and don't use the tab key; use the
spacebar instead.
From what you've said so far, it appears this is what you have:
(View in a fixed-pitch font like Courier)
. +------+---------------------------+
. | | |
. | [10R] [20R]
. |+ | |
. [BAT] +------+------+------+ |
. | | | | | |
. | [LED1] [LED2] [LED3] [LED4] [LED5]
. | | | | | |
. +------+------+------+------+------+
1. What is the battery voltage?
2. Is there an ON-OFF switch anywhere?
Where?
3. Are the resistors shown in the correct locations?
3. Are the resistors brown-black-black-gold and red-black-black-gold
or brown-black-brown-gold and red-black-brown-gold?
Or something else?
J
John Fields
I forgot... what color are the non-blinking leds?
M
Mint
LEDS
ng
=A0 =A0 |
[20R]
=A0 =A0 |
=A0 =A0|
=A0 =A0|
Non-blinking LEDS are clear.
Battery voltage is 4.5 Volts D.C.
It has an on/off switch, one side of switch turns on 4 Leds which serve as a flashlight, the other side of switch turns on the blinking RED Led.
Resistor values are what my pics shows, under Notes:
in the ON position, the flashlight array will throw a steady light and the red LED will be dark.
In the OFF position, both the flashlight array and the red LED will be dark.
In the BLINK position, both the white LEDs and the red LED will flash at the same rate.
That is, providing the LED looks like a low-valued resistor when it's on and a high-valued resistor or an open circuit when it's off. If it doesn't, then the circuit won't work.
Earlier, I made the assumption that the flashing LED was dropping about 1.2V with 165mA through it, but neglected to add in the drop for the flashing circuitry, of which the pass element is in series with the lamp.
The problem is, after having looked at several blinking red LEDs, their voltage drop is all over the place and, not knowing which one yours is, there's no way to tie down the value of R6.
If you have a voltmeter you can measure the voltage across the red LED when it's on and then figure out the value of R6 like this:
That'll give you the value of R5 for 20mA into the base of Q1, which should be enough to let the red LED flash and flash the rest of the LEDs as well.
If you don't have a voltmeter, I'd guess at about 2V across the LED when it's on, and about 0.7V across the base-to emitter junction of Q1. Then R5 would be:
91 ohms is a standard 5% part and should work well if the LED will flash with 2V across it.
If it won't, try lowering the value of R6 until it does.
BTW, I have all the parts on hand and they're just pennies, so if you email me with someplace to send them I'll just pop them in the mail and save you the hassle of having to buy them.
Unless that creeps you out, of course. :-(
JF
M
Mint
F
=A0 =A0 =A0 | =A0 =A0
=A0 =A0 =A0 |
|/ =A0OFF |
O =A0/ =A0 =A0|
=A0 |
----+
=A0\ =A0 =A0
I tried testing the voltage across the red LED.
Both leads came off. (Will replace with better wires.) ($3 special from Northern tools. :-)
Will get back with you.
Andy
M
Mint
OFF
| =A0 =A0 =A0 | =A0 =A0
| =A0 =A0 =A0 |
=A0 |/ =A0OFF |
=A0 O =A0/ =A0 =A0|
=A0 |
------+
=A0 =A0\ =A0 =A0
t
I made some jumpers to test things.
I hooked up the red LED wrong, and it went nite-nite.
The other 4 white LEDs still work. :-)
Andy
M
Mint
F
=A0 =A0 =A0 | =A0 =A0
=A0 =A0 =A0 |
|/ =A0OFF |
O =A0/ =A0 =A0|
=A0 |
----+
=A0\ =A0 =A0
John, did you get my email?
Andy
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