CarbOnBal

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.

Parts:

• 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.

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.

Hardware:
I don't expect the basic hardware will change anymore, it has been holding up very well and testing has not revealed any problems. 

Near future:
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.

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.

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!

Wow, doesn't time fly! Its 2018 already.

CarbOnBal basic is well underway by now. I even made a wood (MDF) and plexiglass box for it that looks neat (or it should after I finish painting it) and is quite easy to make without expensive tools or materials. A hand saw, a drill and some screws is all. This sturdy box will protect the electronics and ensure the system can be used in real-world conditions by people wearing size 10 gloves at least. The tiny buttons have been replaced by nice big ones and color coded for ease of use (well, that was the way they were sold).

The battery management system has gone and so has the flammable LI-ION battery. Just a simple 9V block is all it really takes to tune carbs "ad nauseam". I'll add some power saving features to the software when I get it running just to eek out a couple more hours (or days).

The display has a piggy-back I2C adapter which is easy to assemble and disassemble should you ever need to dig around inside the box. 

I'll take a couple of photos soon and post them on the project site.

I'm taking this reduce to the max thing seriously and I hope to have the first 'basic' version available and documented in time for the northern hemisphere's riding season!

Good things are coming your way.. Hang in there!

I've had comments from a few people who were interested in building CarbOnBal and noticed a theme emerging.

There are many people who'd like to build one for themselves but doubt their own soldering skills etc. I've thought about how to help them best and I think the answer is more simplification, not just a step by step guide.

To get to the point where as many people as reasonably possible will be able to build their own CarbOnBal units I've decided to focus development on a basic version first. Once that is achieved and people start building them I will look at implementing a more advanced version.

The first thing I'll do is use a serial I2C display module, eliminating the 74HC595 and associated wiring. This reduces the complexity as far as possible while still having a unit that can sync four carbs or throttle-bodies. The basic version will inherit all the functionality of the current prototype.

The later version will support 4-8 simultaneous connections and probably have a graphic display, lots of RAM, digital waveform diagnosis etc. 

The compromise this requires is that there will be no upgrade path from CarbOnBal-Basic to the advanced version. I will try to build a system to let two units wor in tandem though. I envision this as a master-slave setup to allow tuning up to 8 cylinders at once, albeit on two separate displays. 

Over the last couple of weeks the CarbOnBal software has been enhanced greatly.

• There is now an option to prevent the software from zooming in too far, making the display too jumpy to use in practice. This only affects the relative centered display.
• The display units can be set manually in metric and Imperial units 
• The values indicated can be set to count up from absolute 0 pressure (absolute vacuum) or indicate vacuum relative to the ambient air pressure (detected at startup / reset) This makes it easy to compare the readings to existing systems.
• There's a reset to "factory" defaults setting for when things get screwed up from messing around.
• The smoothing used is now responsive. ie: its smooth when the RPMs are stable, as in when you are trying to compare values, and snappy when you snap the throttle. This makes it much easier to use in practice.

There's also the beginnings of what will ultimately become the manual. For now its just a text document which shows you all the menu options in the system. This should give you an idea of the features this software is loaded with. 

Management summary: Its $%^ Bad-Ass if you ask me!

-------------------

Oh yeah, to get the software you need to visit Github because that's where it lives:

https://github.com/dennisMe2/CarbOnBal

Just download the latest source, a new 'official release is coming soon'. Just get the latest as zip or Git Clone if you are a dev and want to give back to the community.

A couple of people have asked me what this would cost to build.

The answer is if course the usual, "it depends".

For a rough idea I just added up the bill of materials listed here for the exact prototype I built.

When all parts, plus a box are ordered off Aliexpress I come to a total of 56 Euros. If you already have stuff lying around it will be less. I know I spent a good deal less for the prototype because I already had switches, prototype PCB, resistors and capacitors etc.

 The most expensive items are the MAP sensors amounting to 50% of the total cost. The second most expensive item are, hold on to your hats; the four push buttons! I calculated the price using decent push buttons you would mount in a case, not the fidgety PCB mounted ones I have on the prototype. The Arduino modules are cheaper than the Mega328p ICs cost separately. They are in fact dirt cheap, as are the displays.

Now I didn't factor in the soldering tin and odd bits of wire you need. I assume you have a decently stocked electronics setup. If not, you may need to add the costs of a soldering iron and a pair of side cutters etc. In that case it will be as expensive as you want to make it. OTOH, this may be just what you need to reinvigorate that old electronics hobby!

Today I had the opportunity to test CarbOnBal side by side with a CarbTune Pro unit. Not only that but more experienced tuners got their hands on it for the first time and it resulted in a lot of enthusiastic responses.

It took a while to get the damping set up right but we got it tuned in. I'll set this up as default preset in the next version. 

I noticed that one of my vacuum lines was a fair bit longer (more than a foot longer) than the others and this affected the readings a lot. Note to builders: make all the vacuum hoses equally long!

The other thing we noticed right away is that the relative centered display auto zooms way too aggressively. This needs to be more stable because it tends to make the balance look a lot worse than it is. It is in effect 'too accurate' to be easily usable. We ended up using the absolute display to get a good comparison.

Bottom line:

Looks like there will be some software tweaks coming up, and the hardware works well.