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Mr.RC-Cam

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About Mr.RC-Cam

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    RC-Cam Mentor

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    http://www.rc-cam.com
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  • Location
    USA
  • Interests
    R/C, FPV, Embedded Programming, Electronic Design.

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  1. Work on adding TIG mode has begun. It has a dedicated discussion: https://www.rc-cam.com/forum/index.php?/topic/4710-add-tig-function-to-the-sparky-stick-welder/
  2. This is the experimental TIG Function discussion area for the Sparky Stick Welder Project. The TIG feature is being developed github contributor hogthrob. Please post all TIG related HARDWARE discussions in this thread. Post SOFTWARE issues at the Github repository in the open PR #6. https://github.com/thomastech/Sparky/pull/6 Important: Questions pertaining to the original Sparky project should discussed in the main project thread found at this link: https://www.rc-cam.com/forum/index.php?/topic/4605-sparky-a-little-stick-welder-with-big-features/
  3. The physical location of Partom's pot suggests it is the video level adj. So give it a try. It's very unfortunate that the other board is missing the video adj pot. And it appears to be hand soldered and has a lot of flux residue. Disappointing to see.
  4. Thanks for the kind feedback. Sorry, but nothing to offer in that RF power category. After the product quality fiasco with Lawmate, followed by the Racewood factory closure, I evaluated several higher powered 1.3Ghz vTx's. None met my quality / performance expectations. That was several years ago and it doesn't appear anything has changed given what's available today. My workaround back then was to in-house modify an expensive 1000mW vTx from a China supplier (I forget the brand). With our modifications it was a reliable performer. But every sale was at a loss due to market pricing pressures. Did that for a couple years to support our customers. Unfortunately the mods were too time consuming and so we ended sales. Fortunately this was after the FPV market had shifted to 5.8GHz.
  5. These observations are ongoing issues that the suppliers ignore. And the reason for the video calibration tool. You are now getting acquainted with the performance issues that haunt many FPV systems. Along with what you observed, be prepared to find that some systems will alter the video level after you change antennas. And sometimes whenever you change RF channels. These undesirable quirks are due to inadequate RF designs, mostly affecting the 900MHz-1.3GHz systems. I doubt the suppliers care and most users are unaware of these problems. The video cal tool not only allows you to properly calibrate a good set of components, it also helps you identify the bad performers that need replacement. I suggest calibrating the video levels after everything is installed and the desired RF channel has been set. Do the cal with the vTx and vRx several meters apart, preferable outdoors (less multipath from workshop walls). Replace the bad parts in installations that suffer a lot of video level instability as the model is moved around (will cause poor video performance in flight). Whenever **anything** in the FPV model or ground station is altered then repeat the video calibration. You're on your way to experiencing better FPV video performance. Your video diversity system should work better too. Enjoy!
  6. It appears that the two minimOSD boards are not identical, perhaps due to sloppy components. Some ideas to try: 1. Ensure battery voltage is at least 8V when powering the boards. 2. Retest with a different video patch cable connecting the two modules. Should be short, good quality. 3. Check the two boards' video input termination. With nothing connected, use a DMM and measure the Vin input resistance of each board (DMM across Vin & Gnd). They should be identical values (within 1%) that are very close to 75 ohms. If beyond 1% mismatch, replace the resistor that has the worst deviation (so it is a match). 4. There is also a 75 ohm series resistor on the video output of the MAX7456 chip. One end of the resistor is on the boards' Vout pin, the other is at the negative (-) junction of the two 47uF tantalum caps. Check them (meter across Vout and 47uF cap junction), should match within 1%. If beyond 1% mismatch, replace the resistor that has the worst deviation. If the resistor values are good matches then the easy answer is to just use the boards as-is; When you adjust a vTx video level you'll need to set it so that the image results match exactly what you saw in the validation test. That is to say, the upper right "T" area will have a subtle darkness, as displayed in your posted image.
  7. Mr.RC-Cam

    Fleye

    Here we are four years later. The goflye drone's website is 404 and their Kickstarter campaign was vaporware. Some backers are still waiting for their refund. Yikes. https://www.kickstarter.com/projects/gofleye/fleye-your-personal-flying-robot/comments Too many cool sounding Kickstarter launches end up as product failures. Getting your money back is often painful, sometimes impossible. Glad I stay away from crowd funding platforms.
  8. An accurate schematic of the welding machine's PWM controller board could help us design alternate current control solutions. I don't have the free time to reverse-engineer the controller board, but perhaps someone else will volunteer to do that.
  9. I did not find schematics to this welder. Having them would have saved a lot of time developing the Sparky Project. The current setting POT is sourced by the PWM chip's feedback path. I originally planned to use the ESP32's DAC to control weld current but had to abandon that idea because of the welder's feedback configuration. The MCP45HV51 digital POT was a convenient solution.
  10. Surprisingly, this welder runs cool. As a test I burned a half-dozen 7018 rods uninterrupted at 85A and temperature rise was minimal. So I'd say that the IGBT transistors and oversized fan are helping out. In case of overheated silicon this welder has a thermal sensor to shut it down. And Sparky will voice announce the overheat alarm condition. But I have a feeling that this audio alert may never be needed. Oops, indeed I am guilty of a typo. This welder's PWM controller uses a SG3525A, not the SG325 nonsense I typed. - Thomas
  11. In this design, a SG325 PWM controller chip and the IGBT transistors are used to switch (at 30 to 50 KHz) the rectified line voltage for the step-down voltage conversion. These drive the primary of a large Toroidal transformer (seen in the image in my previous post). The transformer's low voltage secondary is DC rectified. The reference patent claims the toroid's ferrite material is a special microcrystalline alloy. The toroidal transformer has independent primary and secondary windings. So the AC input and DC output are galvanically isolated. BTW, the low voltage controller supply (15VDC) is also isolated. It uses a TNY275P series chip and bobbin type transformer. I too have watched YouTube videos where the welder was tripping breakers. But they were using 115VAC outlets (versus 230VAC). A 80A welding current will trip a North American 115VAC / 20A circuit (80A x 26VDC / 0.85% = ~2450W). A dedicated 230VAC 30A-50A outlet is is recommended for common welding machines. The market is flooded with very capable Stick, TIG, MIG machines. So I could have bought my way into welder ownership. But I'm also drawn to interesting challenges and I like to hack. So I took a chance on a insanely cheap Chinese Inverter machine. Despite all its shortcomings, it seems to satisfy my needs. And it has given me the chance to finally try my hand at stick welding, something I've been wanting to do for many years. Exactly! Creating Sparky was interesting and a fun challenge. That's a reward of hacking. Even my failed hacks are a win, since something is usually learned along the way.
  12. Project Update: I upgraded the bus bar that bridges the inverter's output to the positive Dinse style connector. The original aluminum bar stock piece was replaced with copper. Maximum short circuit current increased to 121 Amps (was 102A before mod). I also performed a test weld with some 1/8" (3.2mm) 7018 rod. Peak current increased to 115 Amps (was 96A before mod). The new copper busbar is larger than the original. It's 2mm thick and overall size is 24mm x 100mm. The copper surface that directly contacts the aluminum heatsink was tinned with tin-lead solder. A third mounting screw was added too. See photo above. I highly recommended doing the copper mod to any mini-sized welder that was factory assembled with cheap aluminum bus bars. It's a simple hack with a big reward. No doubt there are more opportunities to improve the welding current. It would be fantastic to find a way to push it to 150 Amps. That seems achievable, especially with some help from the community.
  13. It's now Nov 2019, four years since the last post. Market growth has blown out those 2015 projections. The 2018 commercial market was valued at $14 billion USD. Projections say it will be $43 billion in 2024. All this was started by model aircraft hobbyists that wanted to have fun with technology infused flying machines.
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