[Dr_C]

@Drifter2,

I’m very much enjoying your brushless motor projects - if these would benefit from some application of the smart LED hardware/firmware reconfigured to interface with standard radio control receivers - please let me know. I have a three wire version of the Smart LED which could electrically interface directly onto a servo port (with that tweak to the software you proposed).

Setting up the modified firmware code would take no more than a ‘coffee-break’s-worth’ of effort… dead easy.

Let’s do it.

c

[Dr_C]

One coffee break later…

The modified code has been written and it’s ready for testing.

For pulse repetition rates >500Hz the input signal is considered to be an ‘SSD style’ mark-to-space signal (any ID). This is for SSD decoders and O2 decoders (the latter in O2/SSD hybrid mode).

For pulse repetition rates between 33Hz and 500Hz the input is considered to be a standard radio/control servo control signal (where 1 millisecond pulse is usually the servo midpoint). Hence, It’s set so that a pulse of less than 1 millisecond equals StayStraight and a pulse greater than 1 millisecond equals LaneChange.

For pulses with repetition rates below 33Hz, or DC levels, these trigger StayStraight when at zero volts and LaneChange when at supply volts. This provides input compatibility with SCX decoders (using the voltage signal that normally drives the solenoid plunger).

With Drifter2’s kind and innovative thinking the Smart LEDs are now designed for compatibility with SSD, O2, SCX as well as standard radio control servo control pulses.

Next for some testing :)

c

[slotspeed]

Good to see your project moving forward Dr_C, looks very well thought through in terms of compatibility with the components used from other systems. I admit that for me its a little tricky to follow because I'm not all that familiar with how all the systems work, but it seems you have a logical approach that will achieve a good robust platform/integration, looks like fun.

Hope its not too early for this but what are the minimum suggested requirements/system components for a system say with 8 cars?

Have fun.

[slotspeed]

OK I decided to apply myself and re-read the thread, have I got this right... I could start with a 6 car SSD setup, add the smart LEDs, add a few Oxigen O201 equipped cars and achieve a higher car count while using PC lap counter as the RMS? Sounds like a pretty cool upgrade path for someone who already has an SSD system and wants to run races with more cars.

One application option here is to run six standard SSD cars (strobing on IDs 1-6) and then to add in up to twenty additional cars running O201 decoders with Smart IR LEDs. So that’s a SSD/O2 combined system limit of twenty six cars.

--------

1/ A Scalextric ARC PRO or APB C7042 powered system with six SSD chipped cars plus additional O2 or SCX chipped cars with the latter two types using Smart LEDs for lap counting cross-compatibility. In our trials to date we have focused on 10 cars.

[Dr_C]

Hi Slotspeed,

Thanks for your interest in the above posts. You raise a great question and then your response is a perfect example of a potential usage case. A nice summary - so big thanks for this :)

c

[MrNightdrive]

Always interesting to read what you're working on!
I did some playing around reading Car IDs a few years ago. iD 6 was the one least likely to be read at speed as the frequency was quite low compared to the window of opportunity.
So I presume ID 7 and above are switched to using higher frequencies?
I can't imagine the new IDs being squeezed between existing ones... Too much potential for error. Doppler shift must come into it at some point.

[Dr_C]

Hey MrNightdrive,

I took a slightly different approach to increasing the maximum readable ID number. My method uses four phototransistors in a row along the slot to extend the interaction length. Also I set up ID detection algorithms which require only two identical pulse reads to register an ID detection. The system detects IDs up to 36 at normal racing speeds. I need to measure the maximum vehicle speed for 100% accurate ID detection (especially for ID36 which is the lowest frequency) and report back in due course. It will be fast!

Thanks again for your post and interest.

c

[Dr_C]

Apologies for bringing an old thread back to life. It’s now 18 months since the experimental work on ‘Smart IR LEDs’ was completed, conclusions drawn and the work reported here.

First the name ‘Smart IR LED’ is used because the device is an IR LED with its own tiny microcontroller onboard.

The finalised version of the Smart IR LED uses a ATtiny 6 pin microprocessor, a precision crystal oscillator and an opto isolator. The latter is to accommodate voltage level shifting between the host decoder and the Smart IR LED.

So to recap:

The Smart IR LED can be connected to any SSD decoder or oXigen decoder to translate the decoder IR strobe output from whatever mark/space ratio is in use … to … one of the 36 proprietary IDs of System-D.

As the ATtiny chosen for this work doesn’t contain any user programmable SRAM, the Smart IR LED is pre-programmed with a fixed ID at the point of program flashing (an obvious limitation … but all is fair when testing feasibility).

So what input signal does the Smart IR LED require?

The answer is any of the following:

1/ Any of the six Hornby SSD IDs.
2/ Any of the six Slot.it SP15c/d IDs.
3/ Any of the Slot.it oXigen wireless decoders’ IR strobes either when emulating SSD IDs 1-6 or in O2-SSD hybrid mode.
4/ A simple logic high or logic low (for SCX-A compatibility).
5/ A standard R/C receiver output (pulse length modulation around 1ms mid point).

Method 5 was added thanks to a kind recommendation from Drifter2.

These Smart IR LEDs are quite small (I believe I showed the dimensions earlier in this thread), they exist and they function correctly.

As an interesting point of detail, my most experienced test driver found an earlier version of the firmware locked after about 70 minutes of continuous driving (without any de-slots). This was traced to an overflow of a timing register inside the ATtiny - easily fixed once diagnosed :)

Thanks for reading!

c