A way to control 86 LEDs on 8 outputs with IR control?

[jensmith25]

I have a possible project from a customer who wants to light up a Star Trek Voyager model using Infra Red remote control. The problem I have is that he's planning on using 86 LEDs which, even if rated at 10mA each is 860mA which is too high for a Darlington Driver.

The CHI035 18m2 high power board does have 4 outputs at 1.5amp but that's not enough outputs. Ideally need a minimum of 8 outputs.

Is there a way of doing this easily?

Thanks.

 

[Buzby]

Do you mean he wants to have 86 little LEDs like navigation lights dotted over surface of the model, or are they more like flood lights illuminating the model from outside ?.

 

[jensmith25]

They are all to be inside the model.

This is the list:
Basic illumination 30 white LED
Anti-collision bacons 5 flashing white LED
Base 5 blue LED strip
Bussard collectors 2 red LED
Impulse engine 4 red LED
Warp nacelle 15 blue LED
Position lights A 4 green LED
Position lights B 4 red LED
Position lights C 4 white LED
position lights D 2 green Led
Position lights E/
torpedo launchers 6 red LED
Position lights 2 white LED
Beacon 1 red LED
Shuttle bay 2 white LED

He says he can get them combined to 8 outputs but it's still too many LEDs.

 

[JimPerry]

You seem to have 15 sets of lights - do any of them have to do special effects?

 

[jensmith25]

No, no special effects as far as I know.

Yes, 15 sets of lights but he says he can get it down to 8 sets as none of the Picaxe PCB's seem to have more than 8 darlington driver outputs that I can see. All but one are more than 1 LED so I can't see that I can use input pins as outputs.

 

[Buzby]

If there's no effects required why does it need a PICAXE ?

 

[jensmith25]

Because, as I said in my original post, he would like it controlled by infra red remote control having seen other projects I've done with it.

 

[Buzby]

It certainly looks like you could do a lot more with this. How about using the IR to switch from docked to impulse mode, then to warp drive mode, with the lights all changing to suit, with the engines changing colour and running lights pulsing down the sides. It would look really cool !.

Something I started, but ( as usual ) never finished, was this pinball playfield : http://www.picaxeforum.co.uk/entry.php?199-Pinball-playfield-wallart-project
This used a couple of antique MM5451's, which givea total of 70 outputs at 15mA each. More modern I2C devices are available, but the 5451 is hard to beat.

Even better would be to multiplex or Charlieplex, I got over 500 LEDs running from a 40X2 with no driver chips.

How much space is in the model ? What's the biggest size PCB you could fit ?.

 

[premelec]

@jensmith25 - looks like you could do this even with a 20M2 - I didn't check the IR in pin being ok but it has the 15 outputs - suggest you use a MOSFET for each line of LEDs - the control to a MOSFET is very small and they easily siwtch high currents - you'd need common V- on the LED clusters - you don't say if they will have higher voltage than 5volts on the strings but that isn't really a problem...

 

[hippy]

Yes, 15 sets of lights but he says he can get it down to 8 sets as none of the Picaxe PCB's seem to have more than 8 darlington driver outputs that I can see.

This could be the perfect opportunity to make your own PICAXE board.

Putting a PICAXE and two Darlington Drivers on a piece of stripboard would probably be a good starter project.

 

[bpowell]

On the Intrepid class ships, the impulse engines are blue, not red. Same for the Photon Torpedoes; they haven't been red since 2267.

Also, what about the deflector array? You'll need some Blue LEDs for that...but the deflector array can transmit a variety of colors depending on what type of particle it's being used to transmit...Green, White, etc.

 

[Dartmoor]

The original post mentions a CHI035 high power board.
As I understand things, it should be possible to use this for 8 outputs?
You already mention the 4 x FET but there is the option of the L293D chip to plug in as well?
That gives another 4 outputs that can be used as reversible (H Bridge) to drive 2 motors @ 900ma/1A?
If I am right (usually not!) then those H Bridge outputs can be used as 4 indidual outputs @ 900ma?
Or you could use the reverse polarity to change between groups of LED's? (sorry but I am not familar with what colour lights go with which ship etc!).

Hippy's suggestion that this may be a good time to design your own board is a good idea, but I just question if you need to?

 

[jensmith25]

Thanks for the replies.

@bpowell - Agreed, but I'm not involved in the lighting of it or providing the LEDs in this case, just the remote control capability so it's not my fault if the lighting is wrong. It a complicated situation where my customer is building and lighting the model for his client so I assume it's what that guy wants.

@hippy - Since electronics isn't my strong point I'd prefer to use something off the shelf, especially when it's being sold.

@dartmoor - I saw the motor driver outputs but didn't know if these could be used. Does anyone know if Dartmoor is correct?

I have asked if it's possible to use fibre optics for some of the lighting rather than LEDs to cut down the numbers.

 

[jensmith25]

@jensmith25 - looks like you could do this even with a 20M2 - I didn't check the IR in pin being ok but it has the 15 outputs - suggest you use a MOSFET for each line of LEDs - the control to a MOSFET is very small and they easily siwtch high currents - you'd need common V- on the LED clusters - you don't say if they will have higher voltage than 5volts on the strings but that isn't really a problem...

I think it would just be run off 4.5v/5v. I've used MOSFETs before but wouldn't this get really messy trying to connect them up to each of the 15 outputs?

 

[hippy]

@hippy - Since electronics isn't my strong point I'd prefer to use something off the shelf, especially when it's being sold.

That's a fair point. It would be possible to use two or more PICAXE boards with 8 output Darlington Arrays, have one board take in the IR and instruct the others when to turn on or off.

The CHI030 (18M2) or AXE118 (20M2) would probably be best for what you are attempting to do.

 

[jensmith25]

That's a fair point. It would be possible to use two or more PICAXE boards with 8 output Darlington Arrays, have one board take in the IR and instruct the others when to turn on or off.

The CHI030 (18M2) or AXE118 (20M2) would probably be best for what you are attempting to do.

Thanks Hippy. I did consider this but couldn't find much info in the manuals or on the forum as to how to link the Picaxe boards together. Is there info somewhere on how to do this?

 

[hippy]

Thanks Hippy. I did consider this but couldn't find much info in the manuals or on the forum as to how to link the Picaxe boards together. Is there info somewhere on how to do this?

There is a mention in PICAXE Manual 1 on increasing the number of outputs which involves sending a byte of data using SEROUT to another PICAXE executing SERIN so its output can be set as the sender desires.

Sender:
  SerOut TX_PIN, BAUD, ( %10101001 )

Receiver:
  dirsB = %11111111
  Do
    SerIn RX_PIN, BAUD, b0
    pinsB = b0
  Loop

 

[premelec]

@jensmith25 - a lot depends on your client's specifications - driving lots of LEDs from 5 volts is not very efficient - the individual LEDs use about 1.5 to 3.2 volts depending on color and current. I had in mind various series & parallel LED combinations with higher voltage supplies - minimizing current limiting resistors [only one per series LED string]. E.g. using 12vdc and 6vdc supplies could work well - the 30 whites in 6 parallel strings of 5 each with one resistor in each parallel string running on 12vdc... etc... The MOSFETs would simply be voltage level shifting switches from the PICAXE outputs - they can switch 12 volts or whatever. As far as messy - all the source terminals go to V- and the gates through a 1k resistor to PICAXE outputs - Drain connections to LED combinations to be switched - since the circuitry is repetitive it's not too hard to build and with this many circuits there's always going to be a bit of tangle. BTW I have used common CAT5 or 4 wire telephone wire for hookup - 8 pins on Ethernet cables and plugs - two Ethernet cables gives you 16 wires - I'd probably use a separate V+ wire though you could try it with the CAT5 cable 16th wire which might have too much resistance... and give some flicker.

 

[LilDi]

Here is a cheap IR controller you might be interested in for this project.

http://sparkfun.com/products/13235

 

[jensmith25]

Thanks guys. It looks like the client of my customer has decided to just go with simple on/off switch for his model but I'll keep this all in mind should someone else want to go for the remote control option.