05/24/2019 at 19:44 •
Someone just asked me why it isn't possible to calibrate all four sensors.
The reason is simple, its not a bug, its a feature!
What happens is that the other sensors are calibrated to respond the same as that one (0 in software) 1 in the menu. This means that if that one has a different response curve, after calibrating all four sensors will respond the same way. That actually means its possible that the sensors are responding with less accurate results and that's actually a good thing!
When calibrating a set of carburetors or throttle bodies, we need them all to respond the same way over the full pressure range the engine can produce, so the sensors need to do the same! We are only interested in differences between the cylinders of the same bike, you are not getting a reading and transferring that to another bike somehow. No we are only interested in relative differences between the sensor readings. All sensors could be off by 50% and it would still work as long as they were all off by the same 50%!
Luckily these sensors seldom have more than 2% variation and that is easy to calibrate out. Actually doing this is what makes CarbOnBal crazy accurate.
Don't believe the hype on those expensive electronic units that claim to not require calibration. They never bother to explain why... And no "Advanced electronics" is not an explanation. The only system that actually doesn't require calibration is a mercury manometer setup even the old aquarium hoses (at least in theory!)... The others are just always off by a bit, but they should be within usable tolerance anyway, certainly well within the manufacturers specs.
Compare it to using the old aquarium air lines to tune. You don't care how much liquid is in the tubes as long as all the tubes are the same diameter and one line is not pinched, for example. Nobody takes their aquarium hoses in to get them calibrated, there's no need.
08/25/2018 at 17:58 •
I was experiencing intermittent noise from the boost converter I used to run the system off 2 AA batteries. I tried different capacitors but I just couldn't get it 100% ironed out.
Unfortunately I no longer have a really good high frequency scope to check out what was actually going on. Maybe I should have sprung for a better quality boost board with post regulation or something, but I couldn't be bothered waiting for Ali Express.
In the end I decided to just go with a whopping 6 (yes, six) rechargeable AA batteries and feed that into Vin. That way the Arduino's on-board regulator takes care of voltage regulation, and it does a pretty decent job at 7.2V (much more efficient than at 9V). I haven't done the math but these should last me more than long enough.
The hardest part was extending the housing. But that is still the same ugly-ass MDF board and not hard to do. I just bolted an extension on the back with some left over IKEA screws I salvaged from an old piece of furniture. Looks ugly, weighs a ton bot no more intermittent noise throwing off my calibration and really easy to hook up.
06/11/2018 at 09:18 •
Wouter was my fellow contributor to this project, and a fellow electronics and motorcycling lover.
Unfortunately Wouter recently died in a traffic accident while touring in Luxembourg.
I never got to meet him personally but he was a likeable guy, and a very active member of the Dutch motorcycling community and a couple of classic car clubs also. He will be sorely missed by many, many people. Not least of which are his girlfriend, friends and family.
My condolences go out to all those who feel the loss.
06/07/2018 at 18:31 •
I couldn't resist and after a bit of kicking around I decided to build my own graphical app for the laptop. Its written in Java and should run on Mac, Linux and Windows.
This allows me to simulate an attached engine for easy and faster debugging. It also has the added advantage of not waking up, or gassing, the neighbors kids.
What it also does is provide lots of cool new ways to visualize and save the data coming out of CarbOnBal. In the first prototype version I have Bar graphs, a running plot and four gauges, which pretty much covers the ways we all used to balance our carburetors, for nostalgia's sake!
Right now its clunky and probably broken in more ways I'd care to count but ts a start and I figure it will be a great addition, especially for those looking to balance 6 carbs.
The software lives in its own location:
Right now its pre-alpha so you're on your own! I'll let you know when it becomes usable.
05/19/2018 at 19:14 •
Just a quick update to let you know what's up!
I'm getting to the stage when I need to clean up some of the clutter that has made its way into the code. I have three different approaches to calculating averages and I need to settle on what works best. Probably a mix of the different approaches.
I also added a diagnostic (text only) display to help me see what's going on under the hood. I might even leave that in, it seems to have merit now that I have come up with a good responsive averaging method.
Planned is a Bluetooth interface to a mobile phone or tablet which could run an app to support up to 6 carbs, much better graphics and advanced diagnostics etc. This is one for the long term though, and I may let it go if it turns out to be too involved. We'll have to wait and see where it goes.
Its also great to hear from those who have built their own units! I look forward to hearing more from you and would love to get your feedback on how to make CarbOnBal even better!
03/03/2018 at 16:16 •
It turned out that the little el-cheapo boost converters I have laying around are a little too cheap to use out of the box. They wrought havoc with my calibration routine and general accuracy.
Luckily I was able to borrow a 'scope' from a friend and come up with a practical (simple, cheap) solution.
What this converter needed was a filter so I tried just slapping a humongous capacitor on the end. I like to keep things simple. Unfortunately the capacitor on its own wasn't working because it caused the switching regulator to unregulate. It needed a proper coil to make what is known as an LC filter. This can be tailored to lose the high frequency switching noise from the regulator and the mains noise which is picked up over the air.
So I unsoldered a couple of coils from an old broken down router I had lying around and tested those, they worked well, very well. I also tested a coil I made from gaffer tape and 1.2m (4ft) of wire I had on stock. I just wound the wire on the end of a marker pen and glued it together with the tape. It works, not as good as the 'commercial 150uH coil I unsoldered, but well enough to not impact the calibration routines.
The capacitor I ended up using was a 470uF 6.3V electrolytic. Small enough to fit well.
Here's a picture of the hand wound coil I tested. That's the purple and black round thing above the center of the LCD screen. You can see the 'scope indicating a ripple of about 4mV which is actually really good. This big a coil will aggravate the 50/60Hz mains hum though, but the capacitor will handle that, no sweat.
To be honest I ended up using a 150uH coil I unsoldered from the old router because it was much more compact and works a tiny bit better. But this will do in a pinch!
It also helps if you mount the boost converter physically farther away from the sensors and Arduino. I ended up sticking it in the same place anyway, because of space constraints, no biggie.
02/25/2018 at 10:18 •
So my 9V battery started to die on me yesterday, which prompted me to go to plan B.
I know a 9V block is one of the least efficient ways of powering an Adruino, but it IS simple and it DOES work. For a while that is. I estimate I got just over two hours worth of run-time out of the one I had.
But I just wasn't interested in buying another mucho expensive 9V block while I had better options lying on the shelf.
The problem is that the Arduino has an on-board regulator that is very wasteful. It was designed to take a higher voltage than 5V and regulate that down to 5V for the Arduino and some accessories.
Thing is, it basically does this by burning off the excess energy. That's kind of like stoking up the fireplace and opening some windows and doors to keep from getting too hot! Arduinos were designed for rapid prototyping, not really for putting them to permanent use, and at the current price of clones I'm not complaining!
Nowadays you can get some ridiculously cheap and easy to use modules that take voltages between 1 and 5V and regulate that up to 5V which we can use for our Arduino. These work by very quickly causing voltage spikes and storing them up in spools and capacitors while constantly regulating the process so the output stays at 5V. It sounds complicated but there's so much call for these today that they have become dirt cheap.
To use these I rigged up two AA batteries in a battery holder and connected the leads to the DC DC Boost Converter. The outputs go to the Arduinos ground and 5V connections.
Here's the big difference, by using the 5V directly instead of the VIn we can bypass the wasteful regulator on the Arduino and save almost half the power. In fact, where CarbOnBal was drawing almost 300mA from the 9V battery (good for a couple of hours total) its down to 150 from the 3V battery its now using (2x1.5V)! These batteries should last me 10 hours or so and rechargeables can be used with no ill-effects.
I've added a schematic to the files section in case you are interested in this option.
- 1 pce. 2x AA battery holder (3x works even better, but wouldn't fit in the case I made.
- 2 pcs. AA batteries
- 1 pce. DC-DC Boost regulator 1-5 to 5V output rated for 250mA minimum
In the Bottom left you can see the tiny module in place. Its stuck in with automotive grade Velcro. The black lead is the battery negative and the red (I ran out of black) that shares its pin is connected to the Arduino GND. Notice the unused VIn pin! The Module's Vo(ut) pin goes directly to the Arduino's 5V pin to power it.
Note that this 'solution' turned out to be too simple. The boost converter I used was too primitive and put out a lot of switching noise and mains "hum". See the next update for a fix.
02/24/2018 at 08:32 •
Time to inform you of how the project's going.
- Since updating the hardware to the current specs I have focused on the software side of the project. These are the things I've been able to add and fix the last couple of weeks:
- Much better calibration system.
You need to calibrate one sensor at a time but this saves memory for other functions and gets a much better result. Also, you can now calibrate incrementally, so each round of calibration adds to the accuracy in stead of replacing the previous data. You can still wipe and start over, per sensor, if you want.
- Advanced menu.
To accommodate the many additions to the menu system I created an "advanced" option which hides a lot of the internal software settings from casual users. Great if you want to lend CarbOnBal to a friend but don't want to confuse him with a bazillion settings!
- Demos and tests.
I added a "Matrix" style demo and also two bar graph self-tests like the digital meters in vehicles have these days. You can disable them from the advanced menu if you get sick of them.
- Reorganized menus.
Just adding advanced menus was not enough. I replaced some features to put them in a more logical grouping, making it easier to find the right setting in one go.
- Dutch language translation.
For those who'd like CarbOnBal in their own language I came up with a simple translation system. It requires one simple change to globals.h to switch to Dutch. Due to time constraints English will remain the primary language and other translations may lag from time to time. Contact me if you need help with any translation, or would like to add one.
- Settings are now saved immediately.
You no longer require a separate "save settings" action.
- An Arduino-IDE compatible mode.
This is for data transfer to a PC. It means you can now do live graphs from the Arduino IDE without requiring extra software. The original mode is still available in case you need accurate (+/- 1ms) timing data.
- removed lots of little and some nastier bugs.
See the commit log on Github for details.
I don't expect the basic hardware will change anymore, it has been holding up very well and testing has not revealed any problems.
I will probably do some additional power options for those who'd prefer AA batteries or Li-Ion. These will be an optional low-cost add-on which you can do after building the CarbOnBal Basic version if you want.
02/07/2018 at 19:56 •
OK, today I received the micro-mini USB adapters I ordered off Aliexpress. That was the last bit I needed to mount the Arduino board properly. Because its quite difficult to access the Arduino USB port through a thick layer of MDF I decided to use an adapter and mount that in the MDF, then stick the Arduino on the end of that and screw down the Arduino with a single screw. Hey, I'm not lazy, I'm efficient!
It may not be pretty or professional but it sure works for me! I now have a flush-mounted micro-USB port!
To celebrate this laudable achievement (ahum) I uploaded some pictures of the insides of the project. I'm not saying you should do it my way, I suggest you do it better and send me the pictures! I'd love to see the results from some of you real crafty folks.
The pictures show all the detail you need to see of the Arduino and sensor mounting, the LCD screen pillars and a bit of the front panel with it's switches in place. The wires are colored making it reasonably easy to track where they go, but I suggest you follow the schematic to see what goes where! I swear I followed it to the letter. The 47uF capacitor is an SMD type I soldered directly to the bottom of the LCD circuit board, so that isn't actually visible. Other than that you should get a pretty good idea of the total project from the gallery.
02/02/2018 at 21:15 •
I managed to simplify CarbOnBal Basic even further.
Testing with the I2C interface board taught me this isn't the way I wanted to go. There are too many variants and they are all different. You lose out on adjustable contrast and backlight. Yuck. It also means you might have to piddle around with the software and I want CarbOnBal to be easy, you know, "doable". So I redesigned it from the ground up with NO NONSENSE!
This means its now just a battery, switch, buttons, a display and four sensors topped off with only three little gizmo's (or discrete components, for purists). Oh yes, and lots of wires. I hope you like spaghetti!
Check out the schematic I just uploaded. It looks a LOT simpler right? I drew the components manually so they would be easy to recognize and wire up, even for first time builders.
I have a working copy of the modified software and I'll upload it "real soon now" ;-)
I started modifying the description and instructions but kackaday threw most of my edits out! Oh well, better luck next time I guess.
Photos and video will follow the software upload so stay tuned!