Using ESU Logic-level function outputs

[peteski]

Are you sure that AUX 3 and 4 on that decoder are logic-level outputs?  Because on the the decoder used in IM SD40-2 AUX3 and 4 are regular (high power) outputs.  The ESU manuals are somewhat confusing (at least to me).

See https://www.therailwire.net/forum/index.php?action=dlattach;topic=40941.0;attach=13239;image


Maybe you could those newly released decoders in your project (they have 6 high power function outputs).

[RBrodzinsky]

Yep, here is the relevant part of the product description from ESU site, and yes, I have already checked the outputs using the LokTester

Shining lighting effects
LokSound Select Micro decoders have 4 function outputs with the possibility of using constant current of 180mA. These outputs can be assigned individually. Apart from that, there are two more non-amplified outputs with logic level. All important light functions like Flash, Gyrolight, Mars light, fire box and so on are provided including the individual adjustment of brightness for each function. Besides D312 Rotary beacon, strobe and alternate flashing, there is a firebox flicker, smart flicker, Mars light, Gyralight, Ditch lights (two types), Oscillating Headlights, Stratolight and many more.


Unfortunately, I would have to perform different surgery in the Kato P42 for the new ESU boards. I know how to make these work, just need to wait for the USPS to declare my package truly lost, and will get new amplifier boards from Bryan at SBS.

[woodone]

Rick,
To put those adapter boards into an N scale P-42 is going to require a big grinder= These adapters are meant for HO scale or larger.
Is that not correct?

[RBrodzinsky]

Jerry, the SBS boards are a 1cm square. Smaller than the little PCB boards I typically use for the SMD resistors and contact points for lights. Will just require some extra arrangements, but not much.  I've also ordered some of the MOSFET chips from DigiKey, both single circuit and double, to play with.
http://www.sbs4dcc.com/aux34functionboard.html

[woodone]

OH! I thought you were using the ESU adapter.
I would guess that the SBS 2115 is what you are waiting for?
I could not find any spek’s on it.
Took me awhile to find the board on SBS web page.

[peteski]

Shouldn't need any adapters. All that is needed per each logic-level function output. is a tiny MOSFET transistor and possibly a resistor.  Basically those outputs seem to be the same as what ESU uses for the rest of the functions on the decoder but, for those two they simply skipped the high-power "amplifier" (actually a switching transistor is a more accurate description).

[woodone]

Well that is what is on this board. Maybe I should have refere as an amplifier board.
You got have away to hook up to the decoder and get the outputs.

[RBrodzinsky]

Shouldn't need any adapters. All that is needed per each logic-level function output. is a tiny MOSFET transistor and possibly a resistor.  Basically those outputs seem to be the same as what ESU uses for the rest of the functions on the decoder but, for those two they simply skipped the high-power "amplifier" (actually a switching transistor is a more accurate description).

That is what I have ordered from Digikey: single circuit (FDV303NCT-ND MOSFET N-CH 25V 680MA SOT-23) and dual circuit (FDC6301NCT-ND MOSFET 2N-CH 25V 0.22A SSOT6).  The single circuit can handle more current than necessary, but was ordered simply because the lower current version (FCV301N) is back ordered until next year. I figured with the single circuits, I can just hang the three wires off of it, and encase in heat shrink tubing. Probably can do the same with the dual (only need 5 wires, since only need one ground wire, and connect the pins) but may make a small board just larger than the chip. $0.33 each for the singles; $0.40  for the duals.

It is the lost shipment from SBS where I had the boards ordered; my holiday weekend searching of the internet is what led to this thread.  Bryan uses a bi-polar NPN transistor, which requires a 10K-ohm resistor; the documents I have found (and linked at the top) show no resistor needed for the MOSFETs.

[peteski]

It is the lost shipment from SBS where I had the boards ordered; my holiday weekend searching of the internet is what led to this thread.  Bryan uses a bi-polar NPN transistor, which requires a 10K-ohm resistor; the documents I have found (and linked at the top) show no resistor needed for the MOSFETs.

I checked the ESU decoder I have and they use a 10k resistor between the logic-level output from the microcontroller and the gate of the function output transistor. I'm pretty sure those are MOSFETs. Adding the resistor doesn't hurt anything and it protects the microcontroller's output from damage in case the transistor shorts out.  Cheap insurance.

[RBrodzinsky]

Thanks. Will do

[RBrodzinsky]

Success!  I received my DigiKey order yesterday, so this morning I hooked up a dual channel MOSFET switch to the logical out inputs on a LokPilot V4 Micro. For these decoders, even Aux 1 and Aux 2 are logic outputs. Here is my test setup

[ Guests cannot view attachments ]

I didn’t have anything small enough to cut traces onto the PC-board for the pin pitch, so just wired directly for this test. I hung 10Kohm 1/10 watt resistors off the Gate (logic input) pins, then connected those to the decoder. The source pins (middle two) are connected to the decoder ground, and the Drain (output) pins go to the LEDs. These are 1206 warm whites, with 1k resistors

Hooked the decoder up to a LokTester/LokProgrammer, and the lights come on when the function button for each was activated, just as it should.

[Sdynamo]

Rick this is a great thread - thanks you for sharing your findings with all of us

[jdcolombo]

Success!  I received my DigiKey order yesterday, so this morning I hooked up a dual channel MOSFET switch to the logical out inputs on a LokPilot V4 Micro. For these decoders, even Aux 1 and Aux 2 are logic outputs. Here is my test setup

(Attachment Link)

I didn’t have anything small enough to cut traces onto the PC-board for the pin pitch, so just wired directly for this test. I hung 10Kohm 1/10 watt resistors off the Gate (logic input) pins, then connected those to the decoder. The source pins (middle two) are connected to the decoder ground, and the Drain (output) pins go to the LEDs. These are 1206 warm whites, with 1k resistors

Hooked the decoder up to a LokTester/LokProgrammer, and the lights come on when the function button for each was activated, just as it should.

I'll probably never need to use this many function outputs given my era (1957), but this is great stuff, Rick.

Did you solder additional wires  to the V4 for this?  If so, can you show us where?

John

[RBrodzinsky]

Here is a close up of the underside of the LokPilot V4 Micro. Starting with the Blue wire, the pads are
    Blue = common +
    Blank = Chg (for ESU PowerPak)
    White w/ black stripe = Ground
    Violet = Aux2
    Green = Aux1
[ Guests cannot view attachments ]

Here is the underside of a LokSound Select Micro. In the lower right corner is the ground wire. The two added wires on the top are
     Orange w/blue spots = Aux4
     White w/blue spots = Aux3
[ Guests cannot view attachments ]

[RBrodzinsky]

And, for 1957, there are always Mars/Gyra Lights, Cab lighting, step lights, etc.   But, I do agree, 4 lighting outputs in N is usually enough.

I've mentioned earlier in this thread, and as can be seen in the photo directly above, I am doing a LokSound conversion for a friend on his Kato P42 Genesis.  As supplied by Kato, there are front and rear headlights and front ditch lights, which take up the normal 4 outputs.  There are "red markers" on the front and rear ends of the locos, made of red plastic.  As I was disassembling the shell, to cut the light pipes to make the ditch lights independent, I realized I could pull the whole interior structure out, an Lo and Behold!, those red plastic markers come out and there are a pair of holes, fully isolated from the other lights.  I put a pair of 0603 Red SMD LEDs, wired in series, into the front and back, and (when this loco gets fully assembled, tomorrow) these lights will now be fully directional and independently controlled from the headlights (just like the model's HO-scale big brother), necessitating the additional two function outputs.  No shell modifications required for these lights!

I will take some photos of this install as I get it together, and post in its own thread.