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Mluvara

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About Mluvara

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    RC-Cam Visitor

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    http://www.rcatsystems.com
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    Silicon Valley
  1. Mluvara

    1W RF Modems

    Cleaning out the office lately and have a few items... QTY 2 Microhard 1W Compact RF modems + manual New were $295 each. These are no longer in production, but are good RF links. Will sell both for $250 shipped in the USA. Good for the experimenter. mike-AT-rcatsystems.com
  2. Cleaning out my office and have a BOB video overlay module laying around. NIB. Note: The version I have is BOB3 http://www.decadenet.com/bob3/bob3.html $75 shipped in the USA. mike-AT-rcatsystems.com Michael
  3. Mluvara

    Old dog, new tricks

    Quite honestly, this doesn't surprise me... That also includes the fact that some are hacking into and adding the modules to other transmitters. Well, technically speaking, it is not a module. I bought it to put in some small electrics and that's all that it will go in. Michael
  4. Mluvara

    Old dog, new tricks

    Haven't flown it yet (tomorrow), but just played with it around the shop. I've heard reports of 2000+ft. Needless to say, I've been curious about the robustness of the link and have been playing with other systems close to it. So far, so good. BTW, the DX6 receiver probably won't handle high current loads required out of larger servos. Michael
  5. Mluvara

    Old dog, new tricks

    Many in the UAV industry have used modems like the Freewave to do r/c ontrol links. The main issue becomes system latency and bandwidth. The Spektrum system is actually DSSS, and interestingly enough, it's an off the shelf wireless usb link. I bought one to play with and it is certainly a neat device for the money. Michael
  6. In the connector world, there are a couple of SMA designations. Specifically, RPSMA (reverse polarity SMA) consists of the pins being swapped in the male/female SMA housings. These connectors are considered non-standard and used on devices where the FCC or other regulating agencies do not want antennas swapped out easily. Simply put, an RPSMA connector will not mate electrically with an SMA. Either, parts will be in the way, or they will screw together and not make electrical contact. Michael
  7. Pressure is pressure. Size of the port shouldn't matter once you build up pressure in the tube. There really is no flow since the pressure sensor has a sealed device at the other end. The biggest issue is to get proper static port placement and make the front of a combined pitot-static probe have a good radius. I use 1/8" pitot-static probes all the time. The dynamic port is 1/16" tubing whereas the outer shell and inner tube form the boundary for the static port. Michael
  8. Mluvara

    Which GPS?

    Speaking of the Lassen IQ, I have some of the older SQ's I'll sell if someone is interested in using them for experimenting. They're 8 channel receivers. Michael
  9. Some quick advice - AOA indicators using pressure are VERY difficult and require special calibrations of the system, including a specially designed probe. They are commonly referred to as five hole probes, because they use airspeed, AOA and AOS measurements (requiring 5 holes), plus a set of static ports. This type of probe also needs to be designed for a specific flight envelope as it is difficult to design one that operates over a wide range and still expect accuracy at the lower end. Simply put, pressure is not linear with airspeed. If you do a pitot-static system for IAS, it is essential you get a good static port measurement. Without it, it's a basically a cr-AT-p shoot trying to reference to fluctuating pressures inside a fuselage. Regards, Michael
  10. Mluvara

    Fuel Level Sensor Success!

    Yes, but it appears that you have a tube inside of the tank. I couldn't get it to work with just a capacitive measurement through the tank wall. The idea was to be non-intrusive to the tank and just add a sensor. It should work fine if you are sensing it with a tube touching the fluid. Nevertheless, it is a touchy circuit and takes some time to implement as you have found. Michael
  11. Mluvara

    Fuel Level Sensor Success!

    Believe me, I spent waaaaaay too many hours with the external strip sensing and had mixed success in developing a commercial offering. Fuel type, content, etc plays a huge role in setup. Not exactly practical for selling an easy to install solution that fits all roles. Obviously, the goal was not to start drilling holes in a tank, but there's really no way around it for some cases (metal tanks,etc). I was also unsuccessful in sensing gasoline or kerosene from the external strips. Senses water well though Good luck with flight testing. Michael
  12. Mluvara

    Speed vs Pressure

    Actually, .5psi is around 170mph. Pressure is NOT linear with airspeed. Michael
  13. Mluvara

    Speed vs Pressure

    Some notes for those trying airspeed measurements: * Measure static outside the aircraft, preferrably on a pitot-static probe, mounted in clean air. * Car measurements will be ok for spot checks, but very subject to turbulent air. In fact, one would need to mount the measurement probe high above or well in front of the car in order to clear the boundary layer. Like airspeed measurements, car testing will be subject to the wind direction and windspeed. Indicated airspeed is not the same as groundspeed. * A good calibration method is to use a manometer. * 1 psi is approximately 240mph * Low speed measurements (<20mph) with a broad range sensor are VERY difficult. Michael
  14. I saw this cool little LCD screen recently at a local surplus house. For those doing video and need a small monitor, it might be handy. Decent quality for $80. http://www.halted.com/store/product45.html Michael
  15. Mluvara

    I2C Circuit Help

    CCS has a really good support forum for their product, Pic C. If you haven't tried asking there, I'd suggest putting a post as there's a lot of knowledge available to help. I've noticed that depending on compiler versions, they have a lot of people reporting bugs. Believe me, I've run into some of them! http://www.ccsinfo.com/forum/ Michael
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