Shane Zettelmier
Project MadMaXX
www.projectmadmaxx.com
Check this out! Electrotek make a product called the Gem2000, and it's much more than just a voltage monitor, it also monitors your whole electronics system for shorts, radio interference, and more. With the electronic system status displayed by the pattern of a super bright blinking light, that was designed to be seen from RC helicopters and air planes, and you can see the condition of your system from hundreds of feet away. Now they've decided to add a new twist for us T-Maxx guys. They've added a lighting kit into the monitoring unit. They have kits available with 5, 7, or 9 lights.
The kit comes with 2 white and 2 red for head and tail lights, and the larger kits come with your choice of white, blue, or amber lights to use for fog, interior, or roll bar lights. You can order extra lights in extra colors, and can get the green too. The lights come 2 to a cord, and have a deans mini connectors so it's super easy to make extensions, swap lights, or have multiple bodies with different lights that can work off of a single monitor unit.
The kit comes with the monitoring unit, lights, metal fixtures, Velcro mount, extra wire, and shrink tubing to extend the wires for custom applications. The main unit that plugs into your receiver, via an open plug or Y cable connector. The 'Y' connectors are pretty easy to find, I was able to find a 'y' connector at my local hobby shop, and see them wherever they have lots of servos and airplane parts.
The lights are super bright, and you can easily see them from several hundred feet away, yet don't take much power at all. I left my battery box (5 AA cell Nimi's) with the lights on for about 3 or 4 hours and it was still fine, with plenty of charge to go out and run the maxx the next day without recharging.
Here are 2 pics of the lights, one with the flash and one without. The one on the left is with the flash. On most light kits, you wouldn't see anything because the flash is so bright, on this shot you can clearly see the blue fog lights, green indicator light, and even the reflection off of the linkage & reflective parts in the picture. On the other pic, I turned the flash off, and put it next to a fairly bright flash light, so you could get an idea of how bright they really are.
I decided to setup a new Ford Excursion running body with a set of the new lights. Instead of using the supplied fixtures, I decided to try and make the lights look like they were more like the real trucks. I wrapped the LED in clear plastic, and glued it to the headlight area of the body, which I masked off and did not paint when I made the body. You can use clear silicone or shoe-goo, and after it's dry, paint it over with some black paint so the light only comes out through the body, and not the interior. Because I used the plastic, It'll be easy to get the lights out when I've trashed that body.
IMPRESSIONS: You will not believe how bright these are. They are LED's and use very little power, but are super bright, about the same as a 2xAA mag-light bulb.
LIKES AND DISLIKES: I like the deans mini connectors it gives it a lot of options for how it can be set up! The lights are super bright and clear.
November/December 1998
Radio World
By Bill Grove
This month I have a review that I am very glad to give. I received this item in the mail and was very pleasantly surprised at the quality of the packaging and the presentation of the product on the package. Even though this product is not very large in size it does a big job very well indeed. I expected some problems with the device at the start but had absolutely none. The product is the battery/voltage monitoring system from Electrotek. The device is very small and compact. It is also very easy to mount in your aircraft due to its small size.
Specifications:
WEIGHT: 8.42 grams with chrome led holder.
Current Drain: .0057 amps (5.7 ma.)
LED Intensity: 3000 mcd plus
10,000 hour life expectancy
Simple plug and play operation
This product passed every test I could conceive of. I started by setting up a precision power supply to check the adjustment setting and to ascertain the cut off points. 25 out of 25 times the GEM 2000 started blinking at 5.95 + .01 volts. This is well within the claimed specifications of the manufacturer and as steady as some mil-spec devices. The system went steady light at 5.935 volts every time I tried (25 tests). I put the LED in a darkened room and turned on the system. What a mistake! The LED is so bright under this condition it is hard to look at. I than installed the unit in one of my aircraft and put it out in bright 95-degree sunlight. I had absolutely no problem seeing the LED in direct sunlight from 5 feet away as long as I was within about 20 to 30 degrees either side of dead center to the LED.
I took the aircraft to the flying field and flew the aircraft through the roughest flight I could including hard touch and goes with no discernible effect on the GEM 2000 nor did I notice any adverse radio problems from adding the device into the circuit. The LED is visible from the ground but you have to look hard to see it when you are flying. The GEM 2000 will and does detect switch faults, including vibration induced failures, bad cells in the battery pack under real time load conditions, will give an indication if you have a servo stall and will tell you if the battery needs recharging. I will continue to fly this unit and will not fly another R/C aircraft without this device installed in the aircraft.
This is a great device and will save aircraft for you, but you have to get one first!!!
Contact Electrotek at www.electrotekrc.com or Toll Free at 1-888-567-2862 for further info and to find out where to get your hands on one.
Till next month safe flying
Floyd
May 1999
Product Review
By George Steiner
GEM 2000 "Electronic Guardian" by Electrotek
An airborne battery alarm condition indicator
Through the years of radio control the concern of the onboard battery in the model always has been a high point with the modeler. The usual routine is checking the battery with an ESV meter on the ground during the use of the model depending on how you feel about those NiCds. Many devices have shown up through the years to give an indication of the power left in the battery but never seem to have a matter of convenience to give the message that the battery was OK or in trouble. As time goes by each new device that shows up for this job gets better and better in simplicity.
A new upgraded product from Electrotek, 14667 Lafayette Cir. Magalia, CA 95954 is the on board multi-function battery driving indicator device to give indications with a very bright LED mounted in a very conspicuous place in your model. This LED is not the typical type, but one that can be seen even in the sunlight from some distance away. It has laser bright brilliance that is outstanding.
What are the functions with convenience and reliability when plugged in an unused channel spot in the receiver? It will show first by a flashing LED that the battery is 4.7 volts or higher when using a standard 4 cell battery. Normal starting point with the batteries just off charge would be about 5.2 volts in the green with a standard ESV. When the battery gets down to 4.74 or lower the LED will be lit in a steady state. At this point some calculations have been made that represent that you have about 25% reserve power left. When the LED is of a very low brilliance or out, your battery is no longer alive and well or the connection to it. These are the three basic conditions of the GEM 2000, but it does have other features that can be recognized by the operation of the R/C system. If you have a loose battery connection, bad switch harness, stalled servo or a low capacity battery by operating the system the LED will be in a steady state to a blinking condition or not on at all to further give details of the power to your R/C system in the model. It gives you the true power load of your R/C system while in use rather then a static minor load of an ESV plugged into the charging jack. This is OK but sometimes can be deceiving. This is a considerable strong point for having the GEM 2000 mounted in use in a model with no heavy wiring being involved. Plug it in and use it philosophy. Electrotek has two versions for mounting the GEM 2000. One with the LED being with flexible wiring as shown in Photo #1 that can be mounted remotely and a second version with the LED right on the electronics board. This version can be mounted right into the side of the models fuselage facing outward with the LED in a chrome holder fastened in a convenient location. Simple, effective and convenient.
Some of the specifications for the nitty gritty that it uses less than 6 milliamps drain when plugged into the receiver and power is turned on. The size is ¾ by 1-1/8" and weight is 8.5 grams when using the chrome LED holder that can be mounted most any place in the model. The construction makeup is of the state of the art design using a programmed microprocessor chip to give accurate set of indication for the values used. The GEM 2000 also can be adjusted for other voltages depending on your requirements. You must have suitable test equipment to make changes on your own, otherwise order the GEM 2000 for a 4 cell or 5 cell is recommended. The unit can also be ordered with most any type of servo connectors depending on your R/C system use. What is this little gem going to cost you? The published retail price at this time is $39.95 (street price under $25.00). The Electrotek company has a toll free phone number you can call for more information or ordering a unit by dialing 888 567-2862. They also have a Web page if you are curious and have a PC. www.electrotekrc.com. Great after market add on device.
November 1998
RCOnline.com Product Showcase
Edward Walker
What is it?
The GEM 2000 is an "electronic guardian". Basically it is an onboard battery monitor that instantly tells you whether everything is OK to fly... as soon as you turn on the model.
Why did I choose this product?
It has been selected for the RCO product showcase because it is an exceptional product that I can offer to you with confidence... the confidence that you will be completely happy with it.
I have come to rely on the GEM2000 in my modeling. I think that every modeler, whether they have airplanes, helicopters, cars or boats would benefit from having one.
Introduction
The new Electrotek Gem 2000 is an improved version of Electrotek's already impressive BVMII. I have several of these units and I use them with all of my helicopters and my airplanes. I also own some "other brands" of onboard battery monitors, but I no longer use them. Why? Because this one works better.
With the other brands of LED monitors I have, I cannot see them while flying or for that matter, even in normal daylight. To check my batteries with every other type of onboard monitor I have owned, I have had to walk up and "cup" my hand around it to see the LEDs.
I have been using the Electrotek products for quite some time now (a year?.) and it has become one of those "how did I ever live without" items.
Not your average LED...
The reason I really like this unit is because I can easily see it in sunlight. I can even see the GEM2000 in flight! I have had my helicopter hovering 50 feet away and had people come up and say "what is that blinking light?"!! ...I have it mounted in my helicopter. It faces rearward so I can see it during most of my flying (tail in). In my airplanes I usually mount it under the wing. I can even see it during a flyby!
It couldn't be easier...
The unit is simple to install. You simply plug it into any open receiver port, or into a Y-adapter (if all of your receiver sockets are in use). That's it. If you turn your model on, the GEM2000 is instantly in use and you instantly know how your batteries are doing.
Never again will you...
forget to turn the power off. With the GEM2000 I now never forget to turn off my models when done flying. With other battery monitors I have forgotten to turn off my models and not noticed. Have you ever [gone] over to fire up your model and found that it is already on?
With this unit blinking so brightly on your model, you will never leave it on by mistake again. It gets your attention so there is no doubt that your model is on... even in broad daylight.
Jan-Feb-Mar 1999
From the Ground Up
by Steve Campbell
GEM 2000 Onboard Battery Monitor
I have been wanting to try this gadget ever since I first saw it advertised on RCOnline. The GEM 2000 has a very bright LED mounted directly onto the device's circuit hoard. This is more of a beacon than a traditional LED. It reminds me very much of the old "gumball machine" flashing lights that were mounted on most police cars when I was a kid. Trust me, you won't be able to miss this one, even under a heavily tinted windscreen.: And there are no different light configurations to figure out. If the LED is flashing, you're safe to fly; If it is not, stay on the ground. Easy enough.., but how does it know?
Low amperage is just one of several battery evils that can kill your model. Low voltage is another. Expanded scale voltmeters were devised to check for these two problems. However, unless the ESV puts an actual load on the battery, simulating flight conditions, whatever leading you get is worthless. The manufacturer claims that the GEM 2000 uses the model's entire onboard electrical system for a load. Here's how it works; all electrical energy in all airborne flight pack system (which includes battery, servos, and switch) goes through the receiver. When plugged into a vacant or shared receiver channel, the GEM 2000 now has access to this energy. It can detect a multitude of problems, from a low battery to a binding servo. The latter can be particularly important in a helicopter, because, a push-pull linkage that isn't right can bind up a servo. Sometimes the servo will buzz and let you know, and sometimes not. A binding servo will draw excess current; the GEM 2000 sees this. A damaged circuit trace in your receiver, which will not manifest itself if the battery alone is checked with an ESV (and the servos are at rest), will be detected by the GEM 2000 when the system is put under load. Simply cycling all the servos together creates this load; after the light pack is turned on and the transmitter is on, "stir" both sticks around a bit at the same time. This loads the system much more than a typical ESV, which usually puts no more than a 500 milliamp load on the battery: 'While standard servos draw only about 60 milliamps, the more commonly used super servos or BB scoreless servos can draw well above 100 milliamps each, and all of them working together far exceed what an ESV pulls. The actual load in flight is even higher, due to increased servo demands to propel the machine, maintain lift, and so on. It doesn't take a nuclear physicist to figure out that your basic ESV is not telling you the whole story, particularly if you only check your battery before each flight. Try checking it after a flight, and you'll see what I mean.
From what I have seen, the GEM 2000 is indeed a better mousetrap. When the battery is above 4.8 volts for a four cell or above 6 volts for a five cell, and there are no problems with the energy path (for example, bad switch wire or servo problems), the LED blinks at a steady rate, telling you all is well. When the LED stays lit constantly, you have a battery problem: low voltage or amperage, a bad cell, what have you. If the LED stays dark or goes dark during the load cycle you initiated, something is wrong with your electronics. Bottom line; if the LED is not blinking steadily, you have a problem somewhere that needs to be found and fixed before you fly.
Here's another interesting tidbit. If everything is good to go, but the battery is just running down through normal use, the LED stops blinking and goes steady at 4.74 volts for four-cell batteries, and at 5.94 volts for five-cell batteries. In effect, the device tells you ahead of time that the battery is about to give it up and is providing a 25% or so cushion of available power before it actually does quit. This is one of those "have your cake and eat it to" deals that sounds too good to be true, but it apparently works as advertised.
This device has been in use by plank flyers for quite some time, and several very knowledgeable and respected plank guys (such as George Steiner, known for his electronics expertise) say that the GEM 2000 does indeed deliver on its claims. Now, our helicopters are a much more hostile environment than most airplanes, and I have always been a hit leery of applying plank technology directly to helos. But electricity is electricity; r/c batteries, receivers, and servos work by the same principles regardless of what they're in. So 1 feel comfortable that the GEM 2000 will be as big a boon to us as it has been to the fixed-wing pilots.
Here's the real news; this puppy sells for only 25 bucks. Bob Johnston al Eleclrotek (the maker) offers a 120-day buyback policy; use it for 4 months, and if you don't like it, send it back for a full refund. There is also a lifetime replacement warranty, including crash damage. Yes, you read that correctly. Bust up your GEM 2000 in a real mainshaft-bender, regardless of the cause, and Electrotek will repair it free of charge (excepting postage, of course). I would say that is about the best deal going, wouldn't you?
This unit was sent for evaluation to Mike, who forwarded it to me. I have been using it for several weeks, with no drama. I have been determined to run my battery down deliberately just to see if that light stays on, but bad weather and other problems have conspired against me. In desperation, I cycled my flight pack, and tried it just after the Alpha 4 kicked over into charge mode. The LED glowed back at me steadily. So I know that part of it works, anyway! I'm a bit excited about this gadget, because it appears to be the ultimate simple (and practically foolproof) method of knowing for sure if your battery has enough juice for - famous last words - "just one more flight." The GEM 2000 also can tell you if something else in the power loop has puked on you, or is about to. Needless to say, I have cut a check to Electrotek, and will purchase several more of these things for my other models. The unit even comes with a nice cylindrical aluminum housing for mounting in a plank or scale hell fuselage. The GEM 2000 is one of the best values I have seen in a while.
December 1998
Dick Pettit
ELECTRONIC GUARDIAN
Several months ago I wrote about a device called the BVM-11, from Electrotek, 14667 Lafayette Cir., Magalia, CA 95954, 1-888-567-2862. The BVM-11 is a device designed to give the user a visible indication of battery condition in the airplane itself.
I just received a brand new version of this item, renamed the GEM 2000, advertised as an "Onboard Multifunction R/C Electronic Guardian''. The 1-1/8 x 3/4" printed circuit board uses surface mount technology for high reliability, and the LED indicator is significantly brighter (they call it "laser bright") than the Previous unit. It can actually be seen in a flying airplane in bright sunlight, giving an indication that the battery system is working correctly. GEM 2000's can be obtained at local hobby retailers preset to 4.8 volts or 6.0 volts, and they can be set to any trip voltage between 4 volts and 10 volts by the user.
The GEM 2000 has three distinct status modes of operation, which coincide with the state of the electrical system onboard your airplane. If the LED is flashing, the battery has at least 30% reserve power. If it is illuminated steadily, the battery is approaching the point at which it needs to be recharged. If the LED is dark, there is a problem with the receiver, switch, wiring, or battery, which should be diagnosed and corrected before flying.
Two versions of mounting the GEM 2000 are available, either directly to the surface, or using a remote LED on an 7" cable. The circuit board can be mounted using double-sided tape or with hook and loop material, both of which are supplied in the package. The LED mounts in either a chrome or a black bezel, and the power cable is plugged into an unused receiver channel. It monitors battery voltage under actual system loads. In the air, the LED indicates battery condition under current flight loads. It is water resistant, weather and fuel proof, has a gold plated connector, and is really easy to install.
I was able to adjust my GEM 2000 to trip at just about any voltage by adjusting the board mounted potentiometer, using a stable power source and an accurate digital voltmeter. I set my GEM 2000 to transition from blinking to steady at 4.7 volts, a little less than the factory set point. Using an ammeter, the steady state current at 5.0 volts was a little more than 9 ma. The average current drain while the LED is blinking is approximately 6 ma, quite close to the self discharge current of the battery itself.
Probably the best feature of the GEM 2000 is the Unconditional Lifetime Warranty. If you ever manage, to damage or destroy one, send it back with $5.00 to cover shipping and handling, and you'll get a new one in return. Also, if you send a letter about your GEM 2000, Electrotek will send you a $2.00 rebate and make you eligible for a monthly and annual drawing for another GEM 2000, and a brand new computer radio system.
The GEM 2000 is available With JR/Hitec, Futaba J, or Airtronics connectors, factory adjusted to either 4.8 or 6.0 volts, at your local R/C hobby retailer. It carries a suggested retail price of $39.95, but actual purchase price may vary. It seems to me that the GEM 2000 is an inexpensive insurance policy for just about any airplane.
1998
Eric Hawkinson
Recently, I have come across a new gadget that I really like. It's one of those things that at first may seem frivolous, but it's actually a pretty useful device. Called the "Gem 2000", the device is a small, light (6-9 grams depending on installation) electronic device that drives a very (VERY!) bright LED. It draws just barely more than the NiCd self discharge current, but it lets you know several important things about your on-board system, When the light is flashing, your pack is in a safe state of charge. When it stops flashing, you need to charge before flying. And if it doesn't come on at all, there is a problem with the pack or radio or some part of the electronics or wiring. Al the most basic level, it will definitely give you an obvious indication that the radio is turned on, and make it pretty hard not to notice if you accidentally bump the switch or forget to turn it off. I could tell you more, but there's an add in this issue that has all the details you need. Ii my opinion the unit with the remote LED is the only one that makes sense for our planes. I've been using these in a couple of helis all summer and they work great and really grow on you.
Warren Cross
I reviewed a product made by this manufacturer last year. I thought it was the neatest electronic device I had seen or used to that time. I received a call from Bob Johnson at Electrotek, about a week ago, he told me of a new and improved unit that he has designed and wanted me to try out and to do a review on his product. Being that I already used the unit on several aircraft, I was glad to try the new unit.
The new unit is called the GEM 2000, it is a battery monitor and a monitor for other units as well. It will tell you if your switch is on, if the batteries are charged, or the charge left is sufficient to fly your aircraft. All this is done by a flashing LED that is mounted to your aircraft, in a place that it can be seen. The unit is very small, only 29 X 20 mm, so mounting shouldn't be a problem. I like to mount mine in the cockpit. The unit simply plugs into an unused channel on your receiver. Bob sends you all the tech info, so I won't go into a lot of detail. The LED has 3 states; flashing, good to fly, steady don't fly recharge your battery, dark don't fly system failure. Simple, that's why I love this unit. You don't have to take wings off to check your battery, just a simple glance and you can see your batteries condition. You can even see it on a slow close in fly by. The new LED is 500% brighter than the other system!
I highly recommend this product for anyone who values their aircraft!
Jim Odino
GEM 2000
There are many on-board battery monitors available and more and more they seem to be the choice in place of using Expanded Scale Voltmeters (ESVs) or Digital Volt Meters (DVMs) between flights. Once again, the driver seems to be that people are basically lazy or too impatient to take the time to use their ESV, whereas it takes almost no effort or time to glance at an onboard battery monitor. Helicopter pilots have taken the lead in this area, probably because they tend to fly very long flights and they want to know if they are reaching a critical low voltage near the end of the flight. If they can see the on board monitor while they are flying, they are ahead of the game.
Some months ago, we reviewed the Electrotek BVM II and said we thought its LED was bright enough that you should be able to see it in a fly-by. Since then, they have developed a new model called the GEM 2000 that is smaller and brighter. It is put together very well using surface mount chip technology and comes complete with cables of your choice. Just plug into an unused channel and you are in business. One model has the LED built into the circuit board and the other has a remote LED that you can locate wherever it is convenient. You can buy it set for 4-cell or 5-cell battery packs. It will flash if the voltage is over 4.75 (5.95 for 5-cell) and come on steady at 4.74 (5.94) and below. This provides more than enough margin with a good battery pack. Once again, I must say it, voltage doesn't tell you anything about the state of charge unless you have a good battery, know that it was changed when you started your flying session, and know that it consistently gives you the same voltage discharge curve Then, and only then, should you trust the on-board indicator or the ESV. So you must know the characteristics of your battery. I use a 5-cell pack with a voltage regulator. In the past, I have shown how one could wire in an on-board battery monitor, but this time I decided to try something else. I plugged the GEM 2000 into the receiver as specified and adjusted it to the point where the LED just started to flash. I then ran the pack down and monitored the results. I finally got to a point where the LED would go steady when I worked the servos. I kept going until finally the LED came on steady with just the idle current of the system. At this point, my pack was at 5.7 and the regulator output at 5.68. This is probably still enough margin, although I normally would charge if my pack is down to about 5.9 because I like to have near half my total battery capacity available at all times and I have no trouble with a quick fast-charge when I get to this point.
Many people believe you must have load on the battery when you monitor the voltage and many will argue that the idle current is not enough. I contend that as long as you make your measurements under the same conditions, you will know where you are on the discharge curve. Therefore, I have no trouble using the idle current load for my measurement during my battery check whether it is done with an ESV or an on-board monitor. Just do it the same way every time and be sure you know you have enough left when you get a given voltage or condition such as going from blinking to steady on the GEM 2000.
GEM 2000 ELECTRONIC GUARDIAN
The Gem 2000 is a full-time, automated, onboard electronic troubleshooter. If, during the preflight check, the onboard equipment - loaded battery pack, receiver, switch harness or servos has a problem - the GEM 2000 will detect it and give the alert. A single "laser bright" LED gives the "go" or "no go" decision. According to the manufacturer, the 3-stage LED can easily be seen in flight in full sunlight. Its features include plug-and-go installation; surface mount technology microprocessor; vibration-, weather- and fuel-resistant construction; 25 percent preset safety margin; and adjustable 4 to 10V operation range. Available with a standard CB-mounted or remote LED, its introductory price is less than $25.
