# Bell222 strobe light project

#### vane

Joined Feb 28, 2007
189
i am going to make an rc helicopter in the shape of a bell 222 and add some strobe lights which will be a sequence of red leds along the nose of the helicopter(cylon eye or kitt scanner), this must be as simple and as light as posible with the component amount as low as possible. it must have around 20 leds. i was wondering if someone could draw me up a circuit diagram, i would want it to run off an input of 4.8v and 3.6v - 4.8v output to leds

i am also gonna be adding some leds that go strobing led 1 for a second, led 2 for half a second, led3 for half a second, one second delay(optional), led 1 for a second, etc. if you could draw a circuit for this, with the same led output voltage and input volts. have any questions please post.

#### vane

Joined Feb 28, 2007
189
according to my dad that first link circuit will just go (1= led1 2= led2 etc) 1, 1 2, 1 2 3, 1 2 3 4, 1 2 3 4 5, 1 2 3 4 5 6, 1 2 3 4 5 6 7, 1 2 3 4 5 6 7 8, 1 2 3 4 5 6 7 8 9, 1 2 3 4 5 6 7 8 9 10, 1 2 3 4 5 6 7 8 9, 1 2 3 4 5 6 7 8, 1 2 3 4 5 6 7, 1 2 3 4 5 6, 1 2 3 4 5, 1 2 3 4, 1 2 3, 1 2, 1 then repeat. what i wanted was like a trail of partly lit leds going behind the fully lit one and what about theother strobes the one that flashes the three leds.

#### lightingman

Joined Apr 19, 2007
374
Hi,The easiest way to do this is using a PIC microcontroler, and programming the sequence in to it.... That way, it is just 1 x I.C and a few other components.Something lika a PIC 16F628 would do the trick, with it's 13 I/O's. In surface mount it could be built very small indeed.....Daniel.

#### thingmaker3

Joined May 16, 2005
5,084
what i wanted was like a trail of partly lit leds going behind the fully lit one
That part was not specified in the first post.

Go with Lightingman's solution. PWM technique will give you your dim trailing lights. I don't know how you'll do 20 LEDs with 13 outputs, but I'm confident there is a way.

#### lightingman

Joined Apr 19, 2007
374
I can't count....In that case (20 LED's) we can just move up to a PIC16F876....Let me have a couple of days to think about it...Daniel.
NO!!! hang on a min,,, arn't the LED's paired end to end, making it only 10...

#### thingmaker3

Joined May 16, 2005
5,084
I guess we'll have to capture a Cylon and dissect it...

#### vane

Joined Feb 28, 2007
189
sorry bout the misunderstanding thingmaker i assumed everyone on this forum would understand knightrider scanner as having, not meaning to be offensive or patrionising
maybe have ten outputs then solder two leds in parallel

also, how do you write the eeprom to the pic?

#### thingmaker3

Joined May 16, 2005
5,084
IIRC, the ugly black car in the TV show used incandescent bulbs in the grille. My memory may well have been dulled by the decades, though.

LEDs in parallel are normally not used because of inconsistencies in current draw and brightness. For this application, they might do all right - who would notice the variation with the "movement" going on? Still, putting them in pairs in series would do the same trick without any variance at all. Tomorrow night when I'm back at home, I'll throw together a quick drawing to show what I mean.

#### lightingman

Joined Apr 19, 2007
374
Hi again,Leave it with me, and I will write the program for you and give it a try. It may take a week or so as I am quite busy at the moment.......If you are happy assembling it, I can program up a PIC for you and stick it in the post......If not, I can build one for you but this will take a couple of weeks because of not getting enough time to get into the workshop......What are your size limits ?????....Daniel.

#### vane

Joined Feb 28, 2007
189
do you write to the pic through a interface plugged in to a pc?

#### lightingman

Joined Apr 19, 2007
374
Hi again,I would write the code using Crownhill's Pic Basic Proton compiler, and program the PIC using Microchip's MPlab with a picstart programmer....Yes, it is all done using a P.C. (well a laptop actualy)..Daniel.

#### vane

Joined Feb 28, 2007
189
it would be good if i could pull the chip out, put it in a reader/writer at the flying field and make the leds do different sequencies, but if i cant make a reader the original program will do fine, i assume you made that writer interface, cant you give me more details about it? thanks, vane

#### vane

Joined Feb 28, 2007
189
would it be possible to make two sequences(the scanner and the strobes)on one processor if it has enough outputs?

#### lightingman

Joined Apr 19, 2007
374
it would be good if i could pull the chip out, put it in a reader/writer at the flying field and make the leds do different sequencies, but if i cant make a reader the original program will do fine, i assume you made that writer interface, cant you give me more details about it? thanks, vane
It is posible to do this by writing the program in the PIC, so that it will accept serial data to program the sequences, and then use a P.C's serial output to send the data....The problem is the time it will take to write a program in V.B. to use on the P.C. to send the data to the PIC. This is the best way to change the data without having to buy the programmer and compiling software, and without removing the chip.....A PIC will be able to do the strobe bit's as well....Daniel.

#### bloguetronica

Joined Apr 27, 2007
1,453
A 555 (CMOS) timer and a 1 of 10 counter (4017) should do, if you want to light one LED at a time.

Also, you can replace the LM3916 by the LM3914, which is the linear version (the LM3916 is a VU meter) and cheaper.

#### vane

Joined Feb 28, 2007
189
ideally i want a trail going behind the leds and using a pic will be better so i can set it to do two "sweeps" then flash all the LEDs twice, etc

so i could wire a serial connector to the module and use my laptop at the field by plugging the serial port at the back. although a serial connector will be a bit heavy, could i solder the serial connector to a light weight connector so i could plug it into the module? then program it, i cant wait till this is finished and amazing all the battlestar fans

#### thingmaker3

Joined May 16, 2005
5,084
Top set has LEDs in parallel. Inconsitencies in the manufacture of the LEDs can result in differing brightness between the two LEDs in a pair. Bottom set has LEDs in series. Same number of solder joints, same number of parts, no problem with brightness difference.

I've been spending some time with Google...

Hollywood writer Glen Larson devised both the Cylons and KITT. He copied the Cylon eye over to the ugly Pontiac because he liked the panning red light.

KITT was designed by Hollywood visual effects guru Michael Scheffe. He also did the DeLorean in Back To The Future

Both the Cylon eye and the KITT scaner were indeed incandescent bulbs.

The helicopter is a cool idea.

#### vane

Joined Feb 28, 2007
189
I'm going half cylon and half airwolf here the front section is gonna be chrome, back will be airwolf black (not as dark) with red and green leds for the horizontal stabilizer left and right and random words and decals, maybe even for a laugh write "this space for rent"
I've got plenty of leds bought 100 of them for an rc car project for the red and green ones i use permanent OHP pens to colour them, ill also have loads of spot lights shining out the bottom, might need a seperate battery so i dont steal all the power from the reciever and end up crashing my new heli