The Official BatMon Web site
Q. Where can I download the BatMon article that was printed in Circuit Cellar Magazine?
A. The article is copyrighted by the magazine, so we are not able to provide reprints. You can purchase back issues directly from them. You will want issue #143, June 2002. You can even order online PDF files of the article. Just request the article with author name Thomas Black. Please contact www.circuitcellar.com.
Q. I understand that BatMon monitors the discharge state on a R/C model's receiver battery. I hear that it uses "battery fuel gauging" technology. What does that mean?
A. The batteries used in R/C applications (NiCd and NiMH) are odd fellows. Determining their state of discharge cannot be done with a voltmeter, other than as a pass/fail sort of effort. Although the expanded scale voltmeter (ESV) method and its LED monitor cousins are popular, some R/C'ers have felt that this method is short sighted. Frankly, a voltmeter cannot tell you how many mAH's are remaining in your R/C battery pack.
Battery Fuel Gauging is a modern technique where the charge and discharge currents are constantly monitored and recorded. By keeping track of the number of electrons that have been consumed, via coulomb counting, it is an easy task to determine what is remaining in the R/C battery pack. The process is a matter of subtracting the consumed current from the battery's known mAH rating.
The results can be reported as a true mAH reading, or scaled into an empty-to-full display value. BatMon can report the results either way. Measurement accuracy is very high, which makes this method MUCH better than using a voltmeter.
Q. I really do not have time to build a BatMon using the magazine information. How much would you charge to make me one?
A. Although we originally had plans to produce an advanced (LCD) version of BatMon for retail sale, those plans are on hold. To our surprise, we discovered that the battery fuel gauging concept was not readily accepted or understood by the modelers we spoke to. It is all a matter of educating the market, something that would take a substantial investment in time and money to accomplish. This issue, along with the already small R/C market size, makes mass-production uneconomical for now.
In the meantime you will need to roll up your sleeves and get out the soldering iron. It is a low parts count endeavor, so it can be built in a couple of hours.
Q. I need technical help on the BatMon that I built. I called Digital Products, the firm that is listed on this web site, and they politely told me that I needed to send my questions by email. What is going on?
A. Digital Products is hosting the BatMon site as a courtesy to the Circuit Cellar Magazine readers. Although they created the original design, it is not a product that they officially sell or support at this time. For your convenience, the main design engineer from the BatMon project has volunteered to provide email support. This is done on his own time and reflects his enthusiasm towards the project. Please send your emails to .
Q. I do not have time to design my own printed circuit board. Do you have any available?
A. [UPDATE: THIS OFFER NO LONGER AVAILABLE]
We currently
have some PCB's available (same as seen in the magazine article). They are
double-sided, through hole, solder masked, and silk-screened. Price is $X
USD (+ shipping). Payment is by PayPal
or money order. Please contact us at
.
Q. I want to buy a BatMon parts kit. Or, at least some of the electronic components. What do you sell?
A. [UPDATE: THIS OFFER NO LONGER AVAILABLE]
We do not
sell a kit, but in an effort to help put a BatMon in your R/C model, we are
currently offering the programmed PIC16C63 for $X + shipping cost. Payment
is by PayPal or money order. Please contact
us at .
For your convenience, all of the components are available from Digi-Key Corp, a respected electronic supplier located in the USA. They sell to professionals and hobbyists alike. The Bill-of-Materials lists all of the part numbers you will need to order.
Q. I discovered that U3, the V-reg IC, is discontinued. Is this IC special, or can I use other 4.0VDC voltage regulator IC's?
A. This part is a TO-92 packaged 4.0VDC low drop out (LDO) linear voltage regulator that is rated at 100mA. Other than being a LDO type, it is really not that special. If all you can find is a suitable replacement in a SMD package, then just use your assembly skills to devise a way to solder it to the existing PCB layout.
Q. I want to modify the firmware for my application, but I cannot figure out how to do it. Can you help me?
A. We currently do not offer software support on a casual basis. We are available for contract work, but frankly, the cost to make even minor changes is not attractive to most hobbyists. Keep studying the code and with some effort you should be able to modify it on your own.
Q. I represent an established R/C hobby manufacturer/distributor and my firm believes that a design like BatMon would make an ideal R/C model accessory. Are you interested in working with us?
A. Absolutely. If you have the marketing muscle to successfully sell it then we would love to talk to you. You will need to demonstrate that you have a large presence in the hobby industry and the experience to support it. You may contact us at .
Please be aware that the BatMon software represents a considerable investment in development effort. It is copyright protected and commercial use is not allowed. It is offered license-free for use in your personal hobby project. If you intend to use the firmware/software (hex files, source code, etc.) in whole, or in part, for possible commercial use, then you must contact us for licensing. This is standard industry practice and we encourage you to respect this request.
(c) 2002-2006 T.Black. This web page is sponsored by Digital Products Company