Optical Chuff Detection for TMCC upgrades

Good work Norm. Full wave filtered DC is better than half wave. One tip, best if you make a thin plate for the backside of the driver to block ambient light especially on spoked drivers. Otherwise light will cause false triggers. I use .010" styrene.

Pete

Norm, I do it the easy way.  It wasn't easy at first, but now that the board is all designed and working, it's easy.

Chuff-Generator

Nice board, still have a few. But you’re ruining my fun!

I just couldn't resist.

Will the Chuff generator board work with MTH protosound. I have been looking for a way to install protosound into a Piko large scale steam engine.

What protosound?  You mean a PS-2 or 3 upgrade kit?  If you have a flywheel DC motor the PS kits have a tach reader.  Johns, is designed for TMCC.  MTH is integrated.  IF your talking about PS-1, that is voltage dependent and there is no logic to read a tach input.  So no to either.

Yes. I’m talking about PS3. Putting a flywheel in the Piko engine is just not possible

Well, the Chuff-Generator also requires a flywheel, so that wouldn't work anyway.  However, as George says, PS2/3 generate the chuffs internally from the flywheel tach pulses.

Norton, I am planning on using the sensor on spoked drivers, painting the backside of the flange black with 4 silver stripes for a trigger. I did play around with shining a flashlight on my sketchy setup and it didn’t seem to affect the sensor.

I will see what happens when I try to set it up. Maybe a small hood made out of brass or styrene could help if I encounter some issues.

I was kind of surprised the sensor could respond to the 60Hz of the half wave dc powering the IR LED. At least that’s what I think was triggering the machine gun chuff.

Random triggers from ambient light will depend on how much IR is in the light source. Cool LED and fluorescent likely won't be a problem. incandescent maybe, sunlight for sure as some fellow club members who used my circuit found out when we setup at a local fairgrounds. Those detectors are very fast, much faster than 60 hz. Being able to mount the detector on the flange will depend on how much is the way. Usually the cast on leaf springs are the problem. On my last install I had to install the sensor below the frame.

Pete

I would suspect that the machine gun chuffs may not be ambient light issues.  I know some boards will do that with hard contacts, and I'm sure light isn't the issue there.

I spent a bit more time experimenting with the RPR-220 but decided to install one of John’s CGs. I am using one of his nice little 5V power supplies (no smoke so no Super Chuffer to get 5V from). I was able to mount the power supply on the tailbeam and had a nice unused smoke switch location for the cal switch, accessible below the flywheel:

I used the ground light output of the CG in the cab by the engineer so he can check his OGR posts before heading out. This is an 0402 LED, the one above the backhead is always on with track power:

Here’s a quick little vid:

I may revisit the RPR-220 on another project. I found I could actually trigger the chuff from a striped axle but need a reliable mount that would allow me to adjust the sensor’s position for best response.

If you feed the chuff from your optical sensor into the R2LC chuff input, that shouldn't get the machine gun chuffs as it goes to the RS board in the serial data.

The filtered DC for the IR LED seemed to cure the machine gunning. I was just being a wise guy powering it with a diode and a 470ohm resistor for experimental purposes. My biggest challenge is fixturing the sensor in a way that it would be adjustable. I figure it could trigger off a driver or an axle for a no-math proper chuff rate. I am so close to getting a 3D printer to make adapter parts for things like this. I was just fartin' around with TinkerCAD to see how quickly things could be cobbled.

Yep, having pure DC for the IR LED is key for sure!

Norm, I like your idea of using a switch for Calibrating the CG. I think I'll mod my engines when I pull them apart for maintenance.

Since you have to spin the flywheel to do the calibration, I just use a pair of mini clips to jumper the cal contacts.

I was able to set my chuff 'live' with the external switch. With ERR cruise I had fine enough control to get a quarter turn on the drivers in cal mode to set the chuff.

Cool Norm.  Truthfully, I've never tried to calibrate under power, I just spin the flywheel.  Usually, I do the calibration before I fully wire it as well, I just use a bench power supply to power the C-G.