You can also use a proportional valve (SMC PVQ valves for example) and a current control switch (can be a push button) to get the full control.
Proportional valves have go from closed to wide open in proportion to the amount of current they receive. That said you can either use a dial type control to change the current, or find an analog push button that controls current (not voltage! proportional valves use DC solenoids, so the voltage must be static).
The two-stage switch doesn’t sound like a bad idea though.
A proportional valve is exactly what we need. Unfortunately the SMC PVQ series is only rated up to 100 psi and the largest opening is 4mm (0.15 inches) which is not large enough for our train horn applications. SMC has a VEP product that can handle up to 145 psi but that is still too low. So we need to find a similar product that supports up to 200 psi and 1/2 inch NPT ports.
I will keep looking but I had hoped that someone out there had already found a solution. It would be really cool to have a knob, button, or lever that lets you manually control the air flow just like a manual valve without running air lines into the cab.
You’re right; I didn’t look into their standard ones too far.
We had them custom engineer 1/2in PVQ valves for this application. Unfortunately we never saw enough interest from customers to make it worth our time to make them. I wouldn’t be surprised if they exist somewhere already though.
If theres a group of you interested in this kind of setup we can look into stocking them.
My truck does have a dedicated website but I am in the middle of upgrading and updating it so I don’t want to publicize it right now. I posted the original site more than a year ago just to share basic info with a few friends and forum members. It quickly got out of hand and I soon had thousands of hits to every page and people from all over the world contacting me for help with their trucks. Some people went so far as to track down my personal unpublished email or phone numbers, call me in the middle of the night or repeatedly during the work week, and two people illegally used financial or government institutions where they worked to get my contact info. I was even offered an expense paid trip to the UAE to go customize a pair of exported trucks, which I turned down due to my day job and family commitments. So please understand that I can’t launch the site again right now but I will perhaps in a few months when I get some of my other projects completed including this train horn upgrade.
The odd thing is that my mods are not anything super expensive or crazy like you see on the reality garage shows. Most of them are basic mods, accessories, and upgrades which have been professionally installed by me, usually to make them just a bit cleaner or customize them just a little beyond what you would normally get. Some of them are very unique devices which I invented and built myself and these are the pages which usually attract the most attention. I even sell a few of the devices when I have spare time to make them, which is rare, but I try to get to it every few months or so. My current order waiting list has dozens if not hundreds of people on it and I try to help them when I can fit the time in.
I just wish I had enough to retire so I could do this full time. I love the work and helping people too so it would be a thrill. Maybe someday…
With all the people buying K3s, K5s, and Shockers I am sure it would sell. Look at how many people buy the Graham White manual valve from you and triple that number for an estimate. I think more people would go for the electric valve since nobody wants to run air into the cab, but many would want the variable control valve. The key would be price-point. Even if the Graham White valve was electric I would never pay more than $100 for a control valve, and I even had a hard time justifying the second optional Shocker valve but I did it. If you could get SMC to make a valve identical to the Shocker but with variable control and the price was around $80 or less then I am sure it would sell like wildfire. Count me in for 2 if you can get them!
I talked to a guy from proportionair.com
his name is larry he said they can make the valve just tell him what parts from their bruchure you need and the application, psi, flow etc. that you want
Thanks aob! I sent a detailed note to the local inside sales rep for my state and gave them the specifications we would need. I will update this thread when I hear back from them.
I haven’t tested anything, but if the electric valve works off of the amount of voltage that is put to it (meaning it opens all the way with 12 volts), if you limit the voltage, it should only open part way right? There you would have to install a “box” with a potentiometer and use your horns that way.
There are several ways to limit the voltage or current to electric solenoid valves. The trouble is that the electric coil has to be designed to operate across a range of settings with reduced voltage or current and it needs to be consistent. Forcing an on-off solenoid to perform like a variable control will result in failure to operate, inconsistent operation, and/or a burned out coil. Most of the electric solenoids operate against spring pressure so they snap open and snap closed. It would be a very fine line to try and hold the middle ground with a solenoid that wasn’t designed to do so. It is possible but I wouldn’t want to mess up my valve through experimenting and I would want consistent, repeatable performance so that I could learn the right touch to produce certain sounds.
No response from the sales rep yet. I doubt they will respond. They are usually only motivated by large corporate sales. I am hoping that someone at HB will call them or a similar vendor and find us a solution.
Dude, that is hillarious! I am sure the space shuttle contains a few of these same valves as well but I don’t have a NASA or Obama budget for my train horn project.
We need something designed for hobbyist, tool, or residential use. Not a high grade commercial product designed to control the temperature of the sun. I never received a reply from my inquiries to SMC or ProportionAir so it appears that they are not interested in individual sales. Too bad HB can’t get them to make a product like this at a reasonable price.
and i have a "couple " mods to boot 
Which sometime when i get a couple hours to sit down and think of them all , i will list em…
