TOPIC:

Before I go too far down the rabbit hole, have a couple questions about hooking up LED's (I did search on here, but couldn't find anything, so please link if I missed it).

Where are people pulling power for their LED's.  Straight off the battery plug, or via a controller, or the VCC plug on the Rx?

Does the Tamiya TLU-01 do anything special or just a glorified switch, plugs, and resistors?
Considering it's about $60, any suggested alternatives?

Cheers,

Personnaly, I build my own lights system. Standard leds plugged on the rx batt connector for a single front and rear system. Or I use a cr2032 cell.  Without resistor and all in parallèle wiring. 

TBH there are so many options it's hard to be specific - you'd have to say what you want to achieve, how many spare channels you've got on your RX & TX, what your budget is, and how willing you are to do a bit of maths & soldering yourself

IMO the only good reason for buying a TLU-01 unit is that it's all plug & play - but you can buy a $10 setup that will do that, and give you more features like brake lights & turn signals. 


The only thing I've written up on LEDs for TB was a bit of an aside in one of the bits on scratchbuilding (tamiyabase.com/...-interiors).



My basic setup now tends to be taking + & - from an unused channel on the RX, and using resistors to drop that down to whatever the LEDs need, or wiring them in series pairs depending if they're close to 3v each, so the basic lights come on as soon as the RX is powered up.  I also like flashing beacons, but don't want them on all the time so I tend to power them off a receiver controlled switch, controlled from a switch or pot on the TX. 



 

There is other solutions with less functionalities than the Tamiya TLU-01, which are also plug'n play while being way cheaper.
If you only want front and rear leds, Carson propose light set, include a switch that could be triggered from a remote (you need an available channel for this). And by the way, you will notice if you search for it that in many places, the kit with 4+4 (white+red) is way cheaper than the 2+2 version...
On a car on which I want the leds to be switch remotely, I would take this in 4+4, even though I would only use in most of the case 2+2 leds.
I part the 2+2 additional leds and keep them for future usage on a car on which I would not need/want a switch (and in that case, I just solder the led in parallel and I instal a servo connector at the end, to plug it on the vcc plug of the RX.

By the way, I never implemented stop lights, reverse light or blinkers as the behavior is based on channel positions, and not as much realist : you would never see a rally car with blinkers switched on on the side the driver is turning the wheel while trying to turn the car in the other direction .

Wow.... Ok more info than i needed
Thanks guys. I'm enjoying this forum more and more everyday!

The Rx are all 3ch + VCC/Batt. My Tx is 3ch and kids 2ch.
At the moment just doing headlights. Sounds like the VCC plug is the way to go.

Turning on/off via Tx was gonna be next ques. My 3rd ch is a switch, so potentially the underbody lights could be on that. Hmmmm.

Parts isn't a problem, and happy to build my own. Messing around with Arduino is another side hobby.

Brake lights yeh...... I've got couple of ideas for some working lights. My understanding of transistors is flakey, so at the moment the brake lights are a bit flakey too   

Cheers,

I've never got on with crimping the tiny JST connectors that RXs use (despite buying the correct tool(s) ) so I cheat & use servo extension leads and/or y-leads to start with


First step is to find what voltage the ESC is putting into the RX, it should be 4.8v to 6v (nb don't use a Tamiya TEU101BK without a separate BEC as it puts out whatever the main/drive battery voltage is) & knowing the figure is more important than what it is at this point. A "cheap" analogue multimeter ($15 or so?) is a good place to start.



LEDs come in lots of varieties, I'd avoid pre-wired as they tend to have the correct resistors for 12v. For headlights, if you want to drive at speed in pitch black, the bigger, brighter & more of them the better. Like 10mm, 10,000mCd (milliCandela, measure of brightness) in white (blue white, ort "cold" white), and lots of them.

For realism though, you're probably looking at fitting them in existing buckets, most likely of 5mm size. In most cases "warm white" is going to look better/older (and if they don't specify "warm", they're not).
Claims are still going to be made that 5mm warm white are "hyperbright" / 10,000mCd etc, but they're not going to perform like that. Wider angle the better really, but often it's a choice between 30 degree & 22.5 degree, or not knowing at all  

You also need to see that the Forward Voltage & current draw (in mA) are stated. The values aren't that important for the moment (they're typically be 1.8 to 3.2v and 20 to 30mA) but you do need to know them. 



LEDs do tend to come in anonymous gripseal bags - so write the colour, size, mCd, fV mA on a bit of card & stick that in.


I've never been that bothered about brake lights, but 400mCd is plenty for brake/rear fogs & would give room to drop them down a bit for normal tail lights. I like rear lights & turn signal/markers to have red or orange (respectively) encapsulation - and that can be surprisingly difficult to find sometimes, with most LEDs having clear/colourless encapsulation regardless of the colour they emit.

7/0.2mm, 7 strand / 1.4A "equipment" wire in a couple of different colours is enough for LED wiring & is fine/flexible enough to keep tidy in an RC car. Small bore heatshrink tube is better than tape, but do get a hot air gun to shrink it - a micro blowtorch is not the right tool

I don't know what you have in the way of tools, but for me a soldering iron is a must, 25w should be delicate enough for this kind of work & still give some flexibility. You can buy a cheap iron, but don't skimp on the solder.



At the risk of bombarding you with too much info, don't get scared off by the resistor maths -  once you gathered your info it's quite straightforward

Resistor needed = voltage your RX is running on, minus the LED forward voltage ... divide that by the LED current draw mA, then multiply the whole thing by 1000.

For example, lets say you measure the ESC output/RX voltage at 6v, and you know your LEDs run on 3v, and draw 25mA.

6v RX, minus 3v LED = 3.  Divide that by 25mA = 0.12. Multiply that by 1000, = 120, so you need a 120 ohm resistor:)



For on/off controlled by your TX, take a look at something like this (hobbyking.com/e...witch.html) as it's a simple plug in. Higher current models work more like a relay to switch main/drive battery current & are more expensive & need more wiring.

Jonny wrote:

6v RX, minus 3v LED = 3.  Divide that by 25mA = 0.12. Multiply that by 1000, = 120, so you need a 120 ohm resistor:)

 

Considering that x leds set in parallel are actually consuming x times the consumption of one, the result would be the the same if you consider one single resistor for the whole circuit, when setting the leds in parallel after the resistor. That maybe very useful as well to deal with the fact that the resistor maybe difficult to place hidden near the light bucket if it is not hidden inside the bodyshell...

And you know what?
I just checked the leds I have been using on all my cars for those which were not coming from Carson led kits. I never really bother about this.
They are all prewired for 12V with a resistor. I generally mount them in parallel, all on the same RX port.
And they just work
Maybe sometimes we are just overthinking

I'm undecided on colour, whether I want to go for realism or just super bright.  For the Comical Frog, I'm leaning towards some bright Ultra Violet/Purple, just because I have some, it's "Comical", and a 6yr old is driving it.  The Comical comes with proper light buckets too, which was a nice bonus.  The Rising Fighter will be a bit more effort, if at all.  The big one will be my Lunch Box.

So this w'ends task will be checking output from the Rx.

Math doesn't worry me, my background is in civil engineering.  And I've also setup a google sheet to do the LED calc's for me   .
Most of my LED are from bulk bags, so yeh I generally use Vf = 2.2 - 2.5V and I = 20 - 25mA.  And then depending how conservative I want to be, add 25% to the resistor value.

silvertriple wrote:

Jonny wrote:

6v RX, minus 3v LED = 3.  Divide that by 25mA = 0.12. Multiply that by 1000, = 120, so you need a 120 ohm resistor:)


 

Considering that x leds set in parallel are actually consuming x times the consumption of one, the result would be the the same if you consider one single resistor for the whole circuit, when setting the leds in parallel after the resistor. That maybe very useful as well to deal with the fact that the resistor maybe difficult to place hidden near the light bucket if it is not hidden inside the bodyshell...

For LEDs in parallel, ideally you want a resistor for each LED.  Series can use a single resistor.  So a short length of wire from the LED to the resistor just inside the car body.

I should have said, "as long as you dimension the resistor for the 4 leds running in parallel instead of one resistor for each leds... Now, that being said, if you run those leds with a rx switch, each of them as its own specifications, which is another point to take into account...

That being said, you may also want to identify the best way to power the leds. If you run only two on the body shell, it is easy decision if the RX is easily reachable when the body shell is removed. This is not the case for every cars. 

In my Turbo Scorpion, It's running with a switch. The switch is fixed in the tub. The rear leds are solder on the switch (they were delivered with the switch). I have 3 additional powered canals available and one of them is powering the 4 leds on the bodyshell (I generally avoid to have more than one single plug to remove when I remove the body shell. and iI would even consider making it thru contacts that are going on near the body mounts to avoid manipulating plugs if it is possible...