Bachmann C-19

Greg Elmassian said:
Using a resistor to drop voltage is a time-honored method for a device with constant current.

dropping 6 volts through the resistor directly states that you have .088 amps through the circuit, i.e. unless the optocoupler is a CONSTANT 88 milliampere load, then you are NOT regulating the voltage to 1.5 volts (and for that matter are you sure your 7.5 voltage is also CONSTANT?

So, you are desiring the optocoupler to be an isolated switch.

so, the absolute max rating on the "transmitting" diode in the 3021 is 60 milliamperes. If your voltage reading is correct, you should have already blown this diode up. It's and LED, so you need to calculate the CURRENT in the transmitting diode, not the voltage, just like an LED headlight.

Once past that, your next hurdle is that the receiving side inside is indeed a triac, which will not turn on and off with DC, used for AC only.

So, if you want to use an optoisolator, you need a different component.

Regards, Greg
Click to expand...
You remember the time-honoured saying that a little knowledge is dangerous :oops::oops::oops::oops:

However, I am tying - very trying :devil::devil::devil:

At least I saved you from having to shoot yourself - although the frustration to my very simple mind is that I can't find a solid state device that will work like a relay - I thought I had that with the optocoupler that I bought. The problem with many components is that all of the information is not necessarily found in one place.

With Google as my friend, having found the optocoupler that appeared, in diagramatic form, to do what I needed, I then in another place found that the feed voltage was fairly low at 1.5v (that figures as there's an LED in it) but it was only when I was searching further after my failed attempt that I found mention of it being a triac and therefore for AC - so three places to find that much info and the third bit too late.

Looking back at Tony Walsham's post about the Mylocosound card - as far as I can make out, while it doesn't need an Annie or Connie type chuff trigger, it's sound pulses don't hook up to the Bachmann optosensors, it relies on voltage draw (unless it's been upgraded and there's more info that's not on Google).

Neil Robinson said:
If you back to the configuration in post number 10 where you state you got it to work with a 9V supply in the tender, does shorting the chuff wires to each other still produce a chuff as before?
Click to expand...

Neil, I think I'll need to disconnect the optocoupler to check that. I've been wandering about thinking what to do, and what is now obvious is to take the optocoupler circuit out.

I'll do that and report back - before I shoot myself >:)>:)>:)>:)
 
yep, get an opto that has a transistor as an output instead of a triac, but I think you will need a bit more logic around it. since this is a C19, I believe the logic will be proper from the "chuff mechanism", that is the output will go to ground when you want a chuff, so you will have to invert the logic so you get conduction on the output when you want a pulse...

I think you will need to invert the logic into the opto with a transistor and resistor... that way the output is stock is "on" only when the chuff is not desired...

active low... but you want active high.

i.e. zero volts from the chuff circuit indicates it wants a chuff... you invert that so the signal is now high when you want a chuff, that high signal drives the led in the opto.

So now when you want a chuff, the output side conducts, and you can use that voltage it is conducting to make the chuff circuit operate.

I think you can use an npn transistor for the inverter, and again I would test your circuit with an led, before hooking in the opto, then you know if you don't get output for your chuff, it's the output side of the opto, not either side.

Greg
 
Greg Elmassian said:
yep, get an opto that has a transistor as an output instead of a triac, but I think you will need a bit more logic around it. since this is a C19, I believe the logic will be proper from the "chuff mechanism", that is the output will go to ground when you want a chuff, so you will have to invert the logic so you get conduction on the output when you want a pulse...

I think you will need to invert the logic into the opto with a transistor and resistor... that way the output is stock is "on" only when the chuff is not desired...

active low... but you want active high.

i.e. zero volts from the chuff circuit indicates it wants a chuff... you invert that so the signal is now high when you want a chuff, that high signal drives the led in the opto.

So now when you want a chuff, the output side conducts, and you can use that voltage it is conducting to make the chuff circuit operate.

I think you can use an npn transistor for the inverter, and again I would test your circuit with an led, before hooking in the opto, then you know if you don't get output for your chuff, it's the output side of the opto, not either side.

Greg
Click to expand...
Yep - I'm totally lost :rolleyes::rolleyes:

I think it's fair to say that the water is lapping at my chin :worried::worried::worried:
 
Last edited:
I don't understand what all this extra circuitry is all about.
Sound systems such as MyLocosound and Phoenix can simply hook up to the standard Bachmann C19 trigger points.
The Bachmann ground must be connected to the MyLocosound ground.
Simples!!!

The only Bachmann Spectrum loco that required chuff signal inversion was the K27 because Bachmann had it back to front. Ever since, every Spectrum loco is easily and simply a straightforward terminal connection.
The Bachmann P'n'P cards usually have a switch to select either 2 x chuffs per rev, or 4 x chuffs per rev.
 
Tony Walsham said:
I don't understand what all this extra circuitry is all about.
Sound systems such as MyLocosound and Phoenix can simply hook up to the standard Bachmann C19 trigger points.
The Bachmann ground must be connected to the MyLocosound ground.
Simples!!!

The only Bachmann Spectrum loco that required chuff signal inversion was the K27 because Bachmann had it back to front. Ever since, every Spectrum loco is easily and simply a straightforward terminal connection.
The Bachmann P'n'P cards usually have a switch to select either 2 x chuffs per rev, or 4 x chuffs per rev.
Click to expand...
Two things Tony - first, thanks for the info on the Bachmann board, that's saved me one job.

Second, you're asking me to prise open my wallet and let the moths out o_O and that's a much trickier task :mask::mask:
 
Rhinochugger said:
Second, you're asking me to prise open my wallet and let the moths out o_O and that's a much trickier task :mask::mask:
Click to expand...
And those moths are so rare, the WWF will need to be alerted.... :eek:
 
Rhinochugger said:
Yep - I'm totally lost :rolleyes::rolleyes:

I think it's fair to say that the water is lapping at my chin :worried::worried::worried:
Click to expand...

You're totally lost, pity us mere morals I've never even heard of an optiwhatsit ;)
 
It's alright, I'm not dead yet.

Mustn't use a relay other wise Greg will go and shoot himself, and we don't want that.

But a reed switch with magnets is OK.

So why not put a reed switch on top of a coil which is connected to the chuff trigger ? Something lice a Peco point motor :rolleyes::rolleyes: I might have one of them - sharrafter get a reed switch though, never had one of them.
 
The relay itself will commit suicide before I get up to shoot myself ha ha!

Funny thing, I was just researching opto couplers yesterday for a similar issue, driving a common cathode bicolor LED from a decoder.

Just mechanically, using the optocoupler was easier. The big thing you need to be sure of is the (hold onto your seats) current transfer ratio, especially the minimum.

For the layman, the opto coupler is a LED next to a photosensitive device, normally a transistor.

This is not inherently an "on / off switch", but the "brightness" of the LED controls how much current flows through the transistor.

What we want here is an "on/off" switch, as much as possible, so we want to ensure that the chuff output (current) from the Bachmann board is basically "transferred" to the output transistor... the more it is "transferred" the easier it is to make sure the output transistor is "fully on".

So, the higher the minimum current transfer ratio of the device, the "easier" (least current) it is to make your output "fully on"....

Many optos have a minimum of 50%, which means if your chuff circuit is putting out 20 milliamps, then you are only guaranteed to get 10 milliamps out of the output. (does not sound good does it?)

I finally found one with a minimum of 300%, which means if your chuff circuit puts out 20 milliamps, then the output should be able to source 60 milliamps... (better!).

The whole thing is about having enough current from the chuff circuit to adequately power the sound system you want, i.e. the current required.

(my desire for myself was I need a number of these running and I was eating up my internal power supply by using too much power).

In any case, the device I settled on was a TPC817D from Taiwan Semiconductor, about 50 cents here in the US and will plug into a 8 pin DIP socket, to make soldering easy.

This device, along with probably 2 current limiting resistors should do the trick easily. (the "D" version is the one with the high minimum current transfer ratio)

TPC817D C9G Taiwan Semiconductor Corporation | Isolators | DigiKey

Order today, ships today. TPC817D C9G – Optoisolator Transistor Output 5000Vrms 1 Channel 4-DIP from Taiwan Semiconductor Corporation. Pricing and Availability on millions of electronic components from Digi-Key Electronics.
www.digikey.com www.digikey.com

You can do it with a transistor too, although then you don't separate the two different power supplies, and by the time you do that and calculate the gain needed for the transistor, it more work in my opinion.

Hope this helps...

Greg
 
Greg Elmassian said:
The relay itself will commit suicide before I get up to shoot myself ha ha!

Funny thing, I was just researching opto couplers yesterday for a similar issue, driving a common cathode bicolor LED from a decoder.

Just mechanically, using the optocoupler was easier. The big thing you need to be sure of is the (hold onto your seats) current transfer ratio, especially the minimum.

For the layman, the opto coupler is a LED next to a photosensitive device, normally a transistor.

This is not inherently an "on / off switch", but the "brightness" of the LED controls how much current flows through the transistor.

What we want here is an "on/off" switch, as much as possible, so we want to ensure that the chuff output (current) from the Bachmann board is basically "transferred" to the output transistor... the more it is "transferred" the easier it is to make sure the output transistor is "fully on".

So, the higher the minimum current transfer ratio of the device, the "easier" (least current) it is to make your output "fully on"....

Many optos have a minimum of 50%, which means if your chuff circuit is putting out 20 milliamps, then you are only guaranteed to get 10 milliamps out of the output. (does not sound good does it?)

I finally found one with a minimum of 300%, which means if your chuff circuit puts out 20 milliamps, then the output should be able to source 60 milliamps... (better!).

The whole thing is about having enough current from the chuff circuit to adequately power the sound system you want, i.e. the current required.

(my desire for myself was I need a number of these running and I was eating up my internal power supply by using too much power).

In any case, the device I settled on was a TPC817D from Taiwan Semiconductor, about 50 cents here in the US and will plug into a 8 pin DIP socket, to make soldering easy.

This device, along with probably 2 current limiting resistors should do the trick easily. (the "D" version is the one with the high minimum current transfer ratio)

TPC817D C9G Taiwan Semiconductor Corporation | Isolators | DigiKey

Order today, ships today. TPC817D C9G – Optoisolator Transistor Output 5000Vrms 1 Channel 4-DIP from Taiwan Semiconductor Corporation. Pricing and Availability on millions of electronic components from Digi-Key Electronics.
www.digikey.com www.digikey.com

You can do it with a transistor too, although then you don't separate the two different power supplies, and by the time you do that and calculate the gain needed for the transistor, it more work in my opinion.

Hope this helps...

Greg
Click to expand...
Sadly that item isn't available in the UK - unless I order 1,000 with a lead in time of 26 weeks.

How about one of these? Again, the 12v versions are only in China, so I'd need a couple of resistors (7.5v feed and 9v load)

249701
 
I've done a lot of research on this... how about posting a link to a data sheet instead of a picture? :)

and I'm sure you could find a vendor that sells the 817d part in the UK, it is a very common part, just getting the higher transfer percentage is the trick.

Greg

ok.. took pity...

so Digikey was the link I supplied...

I went "digikey uk"

got there in a couple of seconds...

then put in 817d in the search....
1 second later got 145 results

narrowed the search to ON semi....

got 2 results

picked the one with 300% minimum transfer

found this:

FOD817D300W onsemi | Isolators | DigiKey Marketplace

Order today, ships today. FOD817D300W – Optoisolator Transistor Output 5000Vrms 1 Channel 4-DIP from onsemi. Pricing and Availability on millions of electronic components from Digi-Key Electronics.
www.digikey.co.uk www.digikey.co.uk

about 2,000 in stock, minimum order one piece.... .43 pound each..

Took longer to type this than to find it.... don't know what to say....
 
Greg Elmassian said:
I've done a lot of research on this... how about posting a link to a data sheet instead of a picture? :)

and I'm sure you could find a vendor that sells the 817d part in the UK, it is a very common part, just getting the higher transfer percentage is the trick.

Greg

ok.. took pity...

so Digikey was the link I supplied...

I went "digikey uk"

got there in a couple of seconds...

then put in 817d in the search....
1 second later got 145 results

narrowed the search to ON semi....

got 2 results

picked the one with 300% minimum transfer

found this:

FOD817D300W onsemi | Isolators | DigiKey Marketplace

Order today, ships today. FOD817D300W – Optoisolator Transistor Output 5000Vrms 1 Channel 4-DIP from onsemi. Pricing and Availability on millions of electronic components from Digi-Key Electronics.
www.digikey.co.uk www.digikey.co.uk

about 2,000 in stock, minimum order one piece.... .43 pound each..

Took longer to type this than to find it.... don't know what to say....
Click to expand...
I had entered the TPC817D into Google and looked at UK suppliers from that - didn't get very far because nobody was stocking on the basis of that search, but equally didn't try any other search route.

Here's the link to th datasheet for the SIP-1A05

SIP-1A05 PAN CHANG | C10496 - LCSC Electronics

SIP-1A05 PAN CHANG $0.6262 - SIP,5.4x19.9mm Reed Relays ROHS datasheet, price, inventory C10496
lcsc.com lcsc.com
 
John S said:
After many hours of experimentation, which proved fruitful for a DCC Animation and Automation project, the conclusion is unfortunately that without some minor surgery on the C19 board, it is not possible to connect up the Annie Sound Card, the two pictures below show the modification.

Probably best to knock the original idea into touch..............and choose another option for sound for this loco.

As for the successful project mentioned above, I'll post some details in the near future.


PS...
The Relay is STILL GOING, shows no sign of fatigue or any inclination towards failure...
View attachment 249719


View attachment 249720
Click to expand...
MMm - thanks John - a bridge too far ??

It was worth a try.

May have to save up in time for Peterborough show :mm::mm:
 
Greg Elmassian said:
I've done a lot of research on this... how about posting a link to a data sheet instead of a picture? :)

and I'm sure you could find a vendor that sells the 817d part in the UK, it is a very common part, just getting the higher transfer percentage is the trick.

Greg

ok.. took pity...

so Digikey was the link I supplied...

I went "digikey uk"

got there in a couple of seconds...

then put in 817d in the search....
1 second later got 145 results

narrowed the search to ON semi....

got 2 results

picked the one with 300% minimum transfer

found this:

FOD817D300W onsemi | Isolators | DigiKey Marketplace

Order today, ships today. FOD817D300W – Optoisolator Transistor Output 5000Vrms 1 Channel 4-DIP from onsemi. Pricing and Availability on millions of electronic components from Digi-Key Electronics.
www.digikey.co.uk www.digikey.co.uk

about 2,000 in stock, minimum order one piece.... .43 pound each..

Took longer to type this than to find it.... don't know what to say....
Click to expand...
That's not UK stock :shake: - there's still a lead time of 9 weeks :eek:
 
Digikey 'UK'
Mouser 'UK'

both supply from the US.. Both deal with customs etc. charges at source. - Excellent! :):rock::rock:

If I order Friday pm, from Mouser, I can track the order over the weekend and it gets to me Monday/Tuesday.

Minimum order for Mouser is about £33.00 for free carriage..


I get parts from Mouser quicker than from Rapid Online, who are in the UK.. Go figure?

John, if you produced that schematic in Pebble, you are a better man than I, Gungerdin. - Not difficult, I agree.
PhilP.
 
PhilP said:
Digikey 'UK'
Mouser 'UK'

both supply from the US.. Both deal with customs etc. charges at source. - Excellent! :):rock::rock:

If I order Friday pm, from Mouser, I can track the order over the weekend and it gets to me Monday/Tuesday.

Minimum order for Mouser is about £33.00 for free carriage..


I get parts from Mouser quicker than from Rapid Online, who are in the UK.. Go figure?

John, if you produced that schematic in Pebble, you are a better man than I, Gungerdin. - Not difficult, I agree.
PhilP.
Click to expand...
Yep it was Mouser who needed an order of 1,000 with a 26 week lead time :nod::nod:
 
You must log in or register to reply here.
Back
Top