# Marching band dad looking for prop design help, LED lighting, random flash

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#### M Smith

##### New Member
First off, I am a contractor, primarily a carpenter. I also am a hobby mechanic (hot rod guy) so while I have mechanical ability, I am not an electronics expert by any stretch. I have partially build a stand alone ecu fuel injection computer system, megasquirt, but all of the parts can in the package with step by step instructions for dummies like me.

My son is in a competitive high school marching band. I donate my time building props for the show they put on. This year, I am building spinning platforms that are 12 feet long, about 2 feet tall. The actual design and construction is complete. Now, the band director want to make them flash, literally.

My idea is to install battery driven LED flashers in the sides of the platforms. 12 or so lights on each side run on a battery installed in the platform. I want to make the lights flash randomly to give them a sparkle appearence. I have 6 platforms and lights need to go on both sides, so 24-30 lights per platform. The lights need to be bright enough to show up under stadium lighting. We typically end up competing on the state level in a professional sports arena, so the brighter the better.

Did I mention since this is a fine arts program in a public school, the entire budget for this comes out of my pocket? I could use specific parts and sources. Designing specific use pcbs is not my expertice. Can anyone give me guidence?

Thanks.

#### Musicmanager

##### Active Member
Hi M Smith, Welcome to ETO .. .. ..

Firstly, I'm no expert .. there are those on here who are and would describe me as a Deputy Assistant Trainee Novice quite rightly, and no doubt they will pitch in if I falter.

Nevertheless, a worthwhile and interesting project ..

Have a look here .. http://www.picprojects.org/projects/480/pro481/#Description

This is the detail of a board that will give you a series of 8 LED's that 'chase' one another, back and forth. I understand that you need 24 - 30 lights, but the microchip has a limit to the load it can handle, around 20mA. However, if you substitute the first LED with a basic transistor that can handle a greater load that will give you more lights than you need. a flashing effect could be achieve by spacing the lights on alternate sides of the platform.

I've recently used this scheme for a project of mine so I know it works well and I still have all the schematics for it and I'd be happy to help/

I presume you are UK based and it would be useful to know a rough area for sourcing supplies at the right price.

S

#### M Smith

##### New Member
Actually US based. But with the internet, we are all neighbors. Not writing code to run the lights is appealing. And yes, I can randomly string the lights. I thought I had a picture of the prop, but don't see the file in my phone.

I will run by my local electronics shop and see what they have that fits this oist you gave. Thanks.

#### Musicmanager

##### Active Member
OK, you're welcome.

As I said I'd be glad to help, and there are many like minded folk on here who have considerably more ability than me.

Let me know how you get on .. .. ..

S

#### MrDEB

##### Well-Known Member
Not to step on musicmanagers toes but the proposed idea is way to overboard.
Look at using a couple of 4017 chips, 2 - 555 chips and several n-mos transistors to drive the large leds.
Will look for schematic etc. When do you need this done because it sounds like you need a total of 6 circuits thus having a PCboard made would be the easiest method.
Will get back to you asap. Look up knight rider circuits

#### Musicmanager

##### Active Member
Not to step on musicmanagers toes but the proposed idea is way to overboard
there are many like minded folk on here who have considerably more ability than me
There you go ... Thanks Mr D

#### Misterbenn

##### Active Member
I agree with MrDEB, Musicmanager's idea is over kill and looks like it would require you program the PIC.

the suggestion by MrDEB is simple and uses discreet parts ... no programming ... and could be made on breadboard if needed.

However for speed and minimum build effort i would suggest:
1) an arduino with transistors on the outputs directly connected to LEDs ... cheep ... easy hardware build
2) Alternatively use an Arudino connected directly to neopixels (programmable LEDS) .... off the shelf solution ... code to talk to LEDs is online already (its easy trust me) .... but cost a bit more

#### MrDEB

##### Well-Known Member
here is a video of method using a 4017 or 74hc4017
the expensive part will be bright high powered leds.
A microcontroller would be the best and most versatile solution but time and ability are a concern.
IMO the 74hc4017 circuit is perhaps your best option unless you want more "patterns" instead of just back and forth.

#### Misterbenn

##### Active Member
This is how you could make a 12 LED flasher, a small amount of simple programming would be needed for the Arduino.
To increase the number of LEDs you could use more of the aurduino's outputs or have groups of two LEDS together like the last LED chain in this picture.

#### Musicmanager

##### Active Member
Guys ..

Whilst I bow to your expertise, I have to say I cannot see how the schemes you are proposing are any better than, or cheaper than the scheme I suggested at the outset.

S

#### Misterbenn

##### Active Member
Musicmanager

From the link you posted you would have to build your own PCB with 5V regulator, PIC, decoupling caps and such. It didn't look like you could just buy the module . I admit you could make the circuit on a breadboard or proto board but its still more complex than just using the off-the-shelf arduino.
Also the PIC would require a PIC programmer.

With the Arduino you just need a computer, and a bit of breadboard work.

MrDEBs solution is nice and expandable. It can be put on a breadboard with relative ease and densest require any programming, which is great if perhaps you don't get along with computers. The only issue with this is the limited number of patters, a micro controller will be more versatile.

The OP has no interest in learning electronics, he just wants something quick and simple (and cheep) which he can throw together with limited knowledge and help. To me that calls for an Arduino, ideally i'd find a shield for the Arduino so the OP doesn't have to do any hardware work at all.

#### Nigel Goodwin

##### Super Moderator
I'm in the software camp (with MM), using either a PIC or another device (such as an Arduino) - the huge advantage of these over crude hardware designs is that they are much more versatile, and easily configured in seconds to change there exact use.

I did this a good many years ago, for a work mate, for use on a floating river display at Matlock Bath, here's a more recent example of the boats:

My device was very simple, using a PIC 16F628 and (if I remember correctly) 4 darlington driver transistors (the design accommodates 8, but he only needed 4 at the time). It was programmed VERY quickly, using a small (and efficient) BASIC compiler I'd written, the simple code is shown below. The data statements have two values, the first is the pattern on the port, the second is the delay time in mS - so it was absolutely trivial to alter. Obviously this could very easily be written using any other language, and it's easy to understand.

Code:
Device 16F628
Freq=4

Data 4, 200, 2, 200, 1, 200, 2, 200, 4, 200, 2, 200, 1, 200, 2, 200, 4, 200, 2, 200 ,1 , 200, 2, 200 ,4 , 200
Data 2, 200, 1, 200, 2, 200, 4, 200, 5, 200, 2, 200, 5, 200, 2, 200, 5, 200, 2, 200 ,5, 200, 2, 200 ,5 , 200

Dim A, CL, B
Define PortB=%00000000
Loop:
For CL=1 To 52
B=B*10
OutB(A)
DelayMS(B)
Next CL
Restore 0
Goto Loop
Stop
End
However, my device was for use at night (as you can see from the video above), and actually used incandescent bulbs as well - and the OP actually specified that it needs to be visible under stadium lights, so 30mA LED's aren't likely to be big enough.

#### Musicmanager

##### Active Member
OK, well I disagree .. ..

1. The notion of either a breadboard or an Arduino on a platform that a marching band is going to march up and down on, to my mind, is asking for trouble.
2. The schematic is very straightforward, it would have to be, or I couldn't have built it. There is a pic attached of two such circuits driving 140 LED's built for Christmas last year.
3. The scheme provides the .hex file, no programming is required; surely somebody stateside would have helped him with that.
4. When you add the cost of an Arduino to the cost of shield, I'm not sure whether 'cheap' has any argument or not ...

The above are the reasons I disagree, not the basis for an argument as I bow to your expertise.

S

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#### Misterbenn

##### Active Member
as ever with engineering there are many many solutions, and most of them will work equally as well.
Its up to the OP to decide what his capability is, and what he has available to him to work with, the school technology block might already have an arduino he can borrow or similar

#### MrDEB

##### Well-Known Member
before we get too far we need to determine design criteria.
need 6 platforms w/ electronics for each
platforms are 12ft diameter, must be light weight
have bright leds around circumference of platforms

There are Leds that are extremely high powered but are upwards of $50 each. Perhaps clusters of leds instead of expensive leds. May not be as bright but costs less and lighter weight. How many leds (clusters per platform??) budget?? with Adrino or Pic you need a code written and a method to load your chip using the decade counter one could cobble together on a bread board but you lose versatility. #### M Smith ##### New Member Let me get a picture of the platform. Right now, it is just a skeleton. We were testing some concepts. The prop is a visual effect that spins manually. It is a diamond shape. At times, a member of the Flag Guard (think baton twirler) will stand on the center of the rotating diamond, other times two may sit on the ends of the diamond and spin, other times marching band will manually spin the prop. I have tried some different "flash" effects using holographic chips and clear coat polysporic sealers (I do some work with epoxies and acrylics for decorative finishes on concrete). From the distances involved, think high school football stadiums and professional baseball stadium, nothing really pops. Would I be better off identifying the light source first, then determine how to control it? #### M Smith ##### New Member Again, this is the skeleton. It rotates on a 12" lazy susan with caster wheels for stability. The battery and electronics will sit in the center, there is a solid base. It will get 3/8" plywood sides, and some more framing to extend the sides from end to end. I would install a hatch to access the electronics. #### Attachments • 124.6 KB Views: 68 #### M Smith ##### New Member What lighting options exist to give a flash or strobe effect? The lighting and electronics are probably coming out of my pocket. Ideally I would like to keep it around$50 per prop. I am already commited to $500 of the material cost through my company, plus my high dollar labor....free. I am not afraid of computers, but other than a laptop I do not have any equipment. I will need some understanding of how this works because I am the guy who will fix it when the kids break it. Last edited: #### MrDEB ##### Well-Known Member a light source would help but then you need a spot light to high light the reflective paint etc. If being covered by a band member then your out of luck. here is a basic circuit using a pic. Programming is not really an issue. A pcboard could be done to save construction costs and time. The light source is really the issue. in the schematic, it has only one output but adding additional is easy. This schematic has a reverse polarity protection that is not necessary if going with a pcb but it still needs a voltage regulator section. I guessestimate about$25-30 per board with 8-10 output circuits.
The pic = $2.50, the mosfet for each led =$1.56, voltage regulator w/ caps = \$2, pcboard depending on size of board.

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