I have installed the Zimo decoder in the USA Train Hudson several times and I used the USA Trains smoke unit.
The Zimo decoders allow you to control the heater element at 3 different values (standing/slowing down, running, accelerating).
The fan is controlled for stopped/idle, running, and heavy load/uphill. The fan circuit in the decoder does have a clamping feature for the fan motor bemf. Newest decoders have 2 fan control circuiits (steam chimney and steam chests, or 2 diesel stacks).
Thanks, Dan. I’m using a G3, so that’s not an option. I’ll figure something out.
The Zimo will drive anything, so will a QSI:
Yes, but those are DCC decoders, right? I already have a decoder, and G3 DCC output certainly can’t drive a smoke unit. I’ll have to use the DCC data to cobble together a driver that directly powers the heater.
Sean or Greg do either of you have the wiring data on that Train Li unit?
the wiring on the smoke unit?
2 wires to fan, 2 wires to heater, just like my video of the USAT smoke unit.
Greg
Eric Reuter said:
Yes, but those are DCC decoders, right? I already have a decoder, and G3 DCC output certainly can’t drive a smoke unit. I’ll have to use the DCC data to cobble together a driver that directly powers the heater.
Eric doesn’t your decoder have a smoke driver that you could put a DCC switch in between the smoke unit and that?
Richard
The G3 has a 3-Amp switched output for an on/off smoke unit. It also has a DCC output, but it’s a low-current driver, meant for sound modules and function decoders.
I think I can use the output of the chuff sensor to determine speed and acceleration/deceleration and control the fan and heater accordingly.
Antenna time. Obviously, with the metal body, the stock G3 antenna would be useless. I built a 1/4-wave whip to mound alongside the boiler among the other pipes to hide it. On the left side, there is also a convenient screw to ground the coax to the chassis.
Here’s the antenna before installation. The little plastic clips snap onto two of the existing pipes.
Here it is installed. The bent the end up to make it less obvious.
The cable snakes up through the slot under the firebox.
And a little paint.
Works great!
Great idea !
I like the idea but I have to ask will being horizontal not vertical hurt the range and on only one side?
thanks Richard
The antenna polarization would be worth considering if the transmitting antenna were fixed and vertically polarized. However, the Anaren module in the T5000 uses a PCB antenna that is a circular trace, so it doesn’t really have a specific polarization - particularly since it’s handheld and constantly changing orientation. Co-polarization (matching polarization) is more important for directional antennas, anyway. A whip like this is essentially omnidirectional in the plane perpendicular to its axis.
But yeah, it would be better to have the antenna up higher and above the body of the engine. It’s a tradeoff between visibility and performance.
As it is, I expect this perform as well as the stock antenna inside of plastic locomotive with no ground plane, surrounded by noise. We’ll see. I was able to get plenty of range in a quick test here at my office, which is a pretty noisy RF environment,
Hi Eric, cool looking antenna. Did you explore a handrail antenna to keep the antenna above the boiler?
Is it possible to make an antenna for 2.4Ghz? For those using the Revolution and RailPro systems.
Hopefully you can visit my layout and we can do a range test of your Hudson. With all that motion of the wheels and side rods.
Don
The handrails would be pretty hard to isolate on this engine. I did first look at using the vertical grab iron on the side of the cab. That’s a possibility, but I ultimately wanted something attached to the frame instead of the cover, since the U.FL connector is a pain in the ass to engage. I don’t think there will really be much difference. I’m not really worried about the moving stuff, since the motor is up in the body. But I would like to try it outdoors.
A whip for 2.4 GHz would only be 1.25". The biggest concern would be loss through the cable and connectors at that frequency. Does RailRro have an external antenna connection?
Actually polarization is important on virtually all antennas that are not circularly polarized. But the biggest thing is what you have identified, get as much antenna outside the loco as possible.
So “whip” in your last post means 1/4 antenna which needs a ground plane. (that indeed is 1.23" long) You hand holding the transmitter does not do a great job, but it helps.
But in the post for the antenna on the loco, you use the word “whip” to describe your antenna, and that does not look like 1.23", looks longer.
If you made a proper 1/2 wave, the length would be 2.46", closer to what I see, but your “whip” looks even longer.
What wavelength did you target for the loco antenna?
I’m not hassling you, I’m interested in your design, and how you decided things, being a Ham Radio operator besides engineer.
Greg
Mine is a quarter wave at 900 MHz (~3.3”) for AirWire. Don was asking about the possibility of a 2.4 GHz version.
My point about polarization was simply that whether the receiving antenna is vertical or horizontal doesn’t really matter if the transmitter’s orientation isn’t fixed or dependable.
The Anaren R09 modules that the current CVP products use come in two versions: one with a UF.L connector and one with a tiny PCB antenna on the module. The T5000 uses the latter. The G3 can be ordered with either.
I’m a fellow ham, BTW - AB1XO
Sean McGillicuddy said:
In this picture is not a Zimo Smoke unit. It is an Aristocraft Smoke unit made to fit the Hudson. Zimo looks close to this because they copied Aristo’s box The Zimo has a round hole at the top. The unit in the picture is oval shape to fit all the Aristo Holes in the underbody !
Good catch Rex… I think in the beginning, Train-Li offered some modified Aristo units.
Greg
I acquired a Train-Li smoke unit. The directions say to drive it at 5 V, which produces no smoke. I think they meant to drive the fan at 5 V, and the heater at track voltage. I built a simple MOSFET driver with a P channel to power the fan, and an N-channel to brake it when unpowered, and hooked it to my function generator. I’m driving the fan at 5 V and the heater at 18 V in the video below. The trigger is a 2 Hz pulse at 10% duty cycle. I’m pleased with the result. I think I’ll likely reduce the heater voltage a bit. I wanted to try 18 V, since that’s the battery I have in the Hudson. The heater is 16 Ohms.
I’ve ordered, but not yet received, a Super Chuffer. I’ll report back on its performance.
Yeah the heater it the Aristo unit is about 4-5 ohms if I remember right.
The cool thing would be a “brake” between pulses to make the “puffs” more distinct. Actually all you need is a diode across the fan right?
Greg