The new heater for Pearl thread II

Damn, and I thought I was going to be able to pick up a used and tuned gas heater when Gordon installs a new one.

This is just a software upgrade. Though, a useful one.

Nice! I'm loving all of the cheap, pre-built circuits you can pick up for next to nothing these days. That should keep you busy for a while and on the road until they start spreading the salt!

One of my friends an EE, does a lot with arduinos Gordon, have you thought of that. 

Ray, what Gordon is trying to do(and will succeed at) is a pretty simple thing. He just needs to vary the pulse speed of a square wave(on-off) at a 50% duty cycle.

Early BN-2 gas heaters had a diaphragm pressure regulator and a weird pump. Diaphragms fail, and there simply aren't any more. Mine worked for a while, but the fuel pump would overheat and then stop working. Or maybe the diaphragm cracked open, I don't know.

Late BN-2s have a solenoid fuel pump, and a set of points on the blower motor to turn the solenoid pump on and off and make it work.

Gordon and my former heaters are the early style, not a chance of using the OE fuel arrangement though. So what to do?

I found a later heater with pump. But the blower motor was non-functional. SO I have a later model pump, but an early heater.

I know, I'll use a 555 timer to make a simple pulse-modulation circuit to turn the pump on and off X times a minute. Simple really. So I made two, and mailed one to Gordon after I verified it works

An Arduino is way more capable than Gordon needs. An Arduino Mega runs Mike and my EFI. But it needs software written for it. I've written some C++ for them, and it's kind of a real PIA.

Gordon, you merely need to measure the resistance of the pot at the lowest and highest pump speeds you need. Then install a fixed resistor(for the one end speed) and a potentiometer that will get you to the other end.

I know what you mean, if you can get a circuit already made it is a big bonus.  In my friends case he has coded Iphone apps, even used an arduino to do an intelligent, or smart blinking  3rd brake light, I guess each person has their favourite tools and skill levels '

He has helped me to do my cruise install and a few other, he can read a schematic in his sleep essentially and he modified and reduced the complexity of the schematic of my cruise down to only two bidirectional toggles ... It was great fun. 

I've been messing with electronics since I was around ten. 

I've done a bunch of Basic, Pascal, and Assembler coding(which really sucks, BTW). I learned a little C++ just for Arduino. I've done servo control, a 4 thermocouple reader with serial communication of data to a remote reader and display with two separate Arduinos.

Now I find code, then copy and paste. Like my EFI, download and bootload the code, it's rather large. And then there's the EFI tester, another download. Not hard at all if you know where to find stuff, and can modify it to your needs.

I think what Gordon is doing is cool, but I wouldn't set the heater's output much beyond 180F. Things get too hot, and you're in a plastic car.

And THAT is why I throttled it back as much as I did.  It works, but is slightly luke-warm-ish.  Considering the time and components I need to make what I have perfect for me, buying this circuit actually saves me time and money.   Using this function generator I can much more easily set up a range of heat on demand by turning a knob.  Easy-Peasy.  It is very much like using a Coleman camp stove.  Start it on a low flame and then turn a knob to increase the flame to what you want.  It's kind of that easy, but instead of a valve creating more or less gas flow you have something that supplies little pulsed squirts of gas.  Run it faster and it squirts more gas and vice versa.

There are a few safety factors included, like a thermo switch that turns on a glow plug when the combustion chamber temp gets too low, a circuit breaker switch for when the combustion chamber temp gets too high and a circuit that keeps the combustion chamber fan running for a while after the heater is turned off to evacuate the chamber of any unburned fuel (although Dan's newer heater has a few more, like a circuit to watch for a flame in addition to combustion chamber temps - it's pretty sophisticated).  

Including a cabin climate control thermostat on mine has been pretty cool and it works great, it just needs a bit more heat output, but that was my own doing.  This new stuff will just be "Rev 01" of my (and Dan's) original work.  If it works, I can spec it out for other people with BN2 heaters with failing fuel pumps (see Danny's note of dead fuel pumps up above) and maybe resurrect a few more of them.  Without this approach you simply can not get BN2 fuel pump parts anymore.  

I, too, got my first Ham Radio license when I was ten and built my own transmitter, an Eico 720.  That was back in the days of vacuum tubes (1960).  In junior high ('64) Science Fair, I built a transistor logic demonstration using Dual J-K flip flops, the basic building block of digital computers (it's basically an electronically latching toggle switch).  Absolutely none of the judges understood what I was showing them.  

I have no idea what you are talking about, but it sounds very, very cool.

Rock on, gentlemen.

Gordon--you amaze me---always have.  In ham parlance I am strictly an Appliance Operator. "Plug and play" is how I roll whenever I can but you actually understand what's going on.  I am not worthy.  Keep us posted on your heater project, pls.  73s, W4LSU 

@Stan Galat posted:

I have no idea what you are talking about, but it sounds very, very cool.

Rock on, gentlemen.

Neither do I, Stan, which isn't unusual.

But I do like to be warm.  That's why I carry a wool blanket in my car.

It isn't that complicated, gentleman. You all know how points work, correct?

On-off-on-off. Dwell is time in degrees around a circle, remember setting the point gap and then checking for correct dwell? Too small a point gap gives you too much coil on time, the coil can overheat. Too big was no good either. Too big and the coil may not fully charge: weak spark. You needed to adjust the gap just right to get proper dwell.

50% duty cycle just means equal time on and equal time off. The circuit Gordon is using(and just like my original 555 timer) generates a square wave, i.e. on(high) then off(low).

Instead of mechanical contact points, the signal is generated electronically.

Then instead of contacts or a relay, the on-off(square wave) signal is sent to a MOSFET(really a high-current) transistor/switch(instead of mechanical contacts). 

Gordon just needs to be careful, because the fan speed of the heater stays the same. I fear that as Gordon increases the fuel(and burner temp!) that the fan won't be able to remove the extra heat generated.

@Stan Galat wrote: 

 "I have no idea what you are talking about, but it sounds very, very cool."

This, from the man who methodically explained the heat retention characteristics of different viscosity fluids without ever sitting through a Thermodynamics class (Both Kathy and I had to take Thermo twice before we "got" it).  Different strokes for different folks.

Every generation needs a "Buckminster Fuller" or a Mary Grace Hopper or a Charles Bolden for inspiration.  Someone who looks at something, sees it lacking and then pioneers a solution to improve it, over and over again.  

Kind of like building the ultimate T-1 engine, eh, Stan?  Something I don't have the patience to do anymore.  Or others on here fabricating custom parts or systems (Like Piperato and Pickett) to make their cars better.  It's fun.

Electronic stuff is simply building blocks, like concrete blocks to a building.  They can be configured in different ways for different purposes.  You just need to understand how they fit.  I had no clue how this circuit worked, but looked into it, it made sense for my application and I'm learning as I go along.  And it's fun.  Besides - You can google "12 volt variable frequency pulse generator",  get a bunch of hits and go from there.  It's a great learning experience.

There are a lot of BN2 heaters out there that are dead because of the lack of fuel pump diaphragms which are now unobtanium because all of the newer heaters use fuel delivery that's similar to what I'm now using.  This is a simple, elegant and cheap way to replace the old dead fuel pump and bring some of those heaters back to life.  There is a bunch of them on eBay all the time and several threads on them on the Samba.  Someone's gonna want something like this.

73's, Jack!  (W4LSU - Louisiana State or Luck of the Draw?)
K1FRV/HR1GSN

I'm an electromechanical guy in a solid-state world. I understand what you are doing, and why you are doing it, and would probably have a pretty good idea how to fix it if it broke.

But the "building blocks" were something I never got into, nor were there good classes for basic electronics in the small-town HS I attended.

Regarding understanding thermodynamics, etc.-- those are physical (rather than electronic) principles. I can "see" what's happening in my mind's eye with heat transfer, flame fronts in combustion, the Bernoulli effect (and how it relates to carburetors and exhaust headers), etc.-- but electronics and DDC logic never "clicked" the way that electromechanical stuff did, which hampers me. If I do go to EFI on my T1, I'll definitely have a lot of questions.

As it stands, I'll probably send my (modern) gasoline heater to Danny for some modification (I'd like the controls/safeties to be greatly simplified).

@Stan Galat , the Electro-Mechanical dude!  My very first job "off the farm" was figuring out relay logic for rotary-phone-based telephone switching systems.  That's what's controlling my heater!  Electro-Mechanical Relays are cool!!

So I got my teeny-tiny logic board delivered, along with the MOSFETs I need for it (and 9 others just like it - if you're gonna buy one, you might as well buy ten!)  Those are essentially like adding a relay to your headlights.  Danny P. uses a MOSFET on his board that works just like a relay:  A tiny positive voltage pulse comes from the logic board and goes into one side of the MOSFET to trigger it and it electronically closes, just like a relay.  The beauty is that it can handle more current that the pump needs.  To make it work with my fuel pump we put +12 volts into the hot side of the fuel pump, then connect one side of the MOSFET to the ground side of the pump, and the other side of the MOSFET to ground, just like putting a relay on the ground side of your headlights.  When it is triggered with that tiny voltage pulse it closes the circuit and pulses the pump.  Seriously, that's all there is to it - a basic building block of a relay with no moving parts.

Anyway, I've been slammed with things to do lately and sandwiching in a few bike rides, but I'm trying to get the logic board drilled to accept the MOSFET so I can get it wired in and start to play with it.  I'm looking for an oscilloscope to borrow so I can see what's going on with the waveforms and frequency and that will let me begin to adjust how fast the pulses come and how wide they are, but can work without it if I have to.  @DannyP or @Michael Pickett   Have you played with one of those $20 dollar DIY 'scopes I see on Amazon or a 'scope app for your phone?

https://www.amazon.com/Treedix...6061659720&psc=1

Life goes on at the "Five Cent Racing Advanced Heater Labs"

@Gordon Nichols, Agreed, MOSFETs are versatile! I had nursed an old tube based analog HP scope from my early twenties until it just couldn't keep up with computer timing speeds. I felt like a super geek when my dear wife bought me a digital USB scope for my laptop. I've had it nearly 10 years and have no complaints. It's been superseded by the manufacturer with this scope: 

https://www.amazon.com/Hantek-...DCFBMGEPJ5MJMVB6QMQ5

I like the idea of a phone connected scope but always worry about the rapid changes in connectors for phones.

Ugh!

I use a MAC!

I’ll check out Hantek, though......   Yah nevah know.

Monthly update for you erstwhile gas heater aficionados and would-be electronic Geeks!

Things have been a bit busy, lately, what with sitting around watching TV or riding my bike looking at leaves, but I have made some progress on this variable-heat gas heater thing.

First, remember that I'm trying to drive a solenoid fuel pump, similar to a Facet, like this:

But a Facet is self-pulsing.  I need something with a range of 150 - 300  pulses per minute or 2.5 - 5 pulses per second.   I already have the pump that can do that, I just need a circuit that can do that, too.

I also need a way of accurately seeing how many pulses are really being produced (it's kinda tough to count them while watching a light or listening to the pump click) so I ended up buying an oscilloscope.  This is an updated version of the USB scope that Mike Pickette's wife bought him (see above post) and you can use it to see waveforms and pulses over time, select the time interval and duration and see it all on a screen.  Pretty cool.

What I bought fits on a computer strip the size of a 4" wooden ruler, it plugs into my Mac for the output screen and the software that runs it and it cost me about $50 bucks.  I've been looking for a decent used 'scope for a few years to use on other projects, so now I'm in Geek Heaven!  In the photo, that is a AAA cell battery on the left, the logic analyzer in the middle and a variable speed pulse generator on the right.  It is amazing how cheap (and small) electronic stuff is these days.

So far, I've been learning about the pulse generator since it came from Amazon/Asia with ZERO DOCUMENTATION!  I've found enough info on the Interweb to figure out how it works, what components do what and I can begin to tailor the pulse speed to what I want. Right now it pulses from about 50 per second to about 5000 per second, but I'll fiddle with a few parts to get me into a range of 150 - 300.  Those parts should be here today and I'll be off and running.   This is almost as easy to change as changing carburetor jets, once you know what's going on and have the right parts.  To do that I needed 2 teeny capacitors but ended up buying a mixed-value-range kit of 180 of them for $7 delivered the next day.  wow.

So that's it.  I'll let you know how this all works ot in the next few days.

Latest Update:

The damn thing works!  (but then, Danny knew it would, eventually...)  

I needed something to test it with after the circuit mod, so I decided to just use a big honkin' ol' 12V relay so you can hear the pulses.  Remember, I'll be driving a solenoid (click-click-click) fuel pump, so a relay makes a lot of sense - it makes the same sound, at least, sitting on my desk.

So I changed the cap, jury-rigged a MOSFET to drive the relay/pump, hooked up the relay and got this:

THAT, my friends, is a heater fuel pump speed in the ballpark's infield of being "perfect"!  I may have to play with it some more to just use the middle 2/3'rds of the range, but that's an easy change, too.  I also have to decide where/how I'll mount the MOSFET (it's a solid-state relay for the pump) and make that look professional, and then get a nice little box to put it in for under the dash.

Now I'll be able to turn the heat up and down just like Danny and Jack Crosby.  

I love it when something I do actually works the way I want....