"Help!" for: Electronics

Discussion in 'New Recruits' started by 23Magnum, Aug 20, 2010.

  1. EVAkura

    EVAkura 405th Regiment Officer

    You can not necessarily just take any battery and hook it up to LEDs and expect them to work properly. You will first need to get your LEDs and find out what voltage they are rated for... then you will need to find out what voltage the RC car's battery pack is. You will then need to (most likely) put in the correct resistor to lower the voltage from the battery so as not to fry your LEDs. I would also suggest installing a two lead on/off rocker switch inline with your positive from the battery pack to the resistors/LEDs. If you need help figuring all this out.. give us a bit more information please (voltage of battery pack, how many LEDs and what they are rated at.
     
  2. dheighto

    dheighto New Member

    " they're having us do projects of our own choice"
    I'm going to put a stereo amp into my helmet (to hear better), but I'm afraid of it amplifying loud sounds too much. So I've been looking for a Auto Gain Control circuit, to squelch the volume when needed, but haven't found one that meets my needs.
    How about that for a project?
     
  3. dheighto

    dheighto New Member

  4. thatdecade

    thatdecade Well-Known Member

    Thinking about you guys :). You could twist wires onto LEDs for your light project, but if you want a long term solution you HAVE to solder the wiring.

    This is the best soldering tutorial I have ever found. Way better then most college classes on the subject.

     
    Last edited by a moderator: Jan 1, 2017
  5. Sgtpearce

    Sgtpearce New Member

    Hey is anyone here Any good with building computer systems or writing code to make stuff work? I want to add a few things to the helmet for LCF purposes and but I lack the technical ability to do what I want. I've seen a few of you guys put cool looking comms attachments on your helmet and I was watching The Forgotten Spartans on YouTube (machinima) and one of the dudes had a com unit on one side and what looked like a projector on the other. I thought that would be cool to have a working com unit so if you go with buddy's you have Coms. And the projector would be near to display a map and set an objective or RV point if any one got lost. Idk if anyone can help let me know.
     
  6. eckoe17

    eckoe17 New Member

    @SgtPearce:

    I am an electronics Engineer...

    Com system isnt that complicated. You could buy a motorcycle com system and attach it inside your helmet. Done.

    I am not sure, what exactly you want to do with a projector. If you have a stationary map and want to point sth out. No problem.
    But if you have a map in your hand or even want a "display" inside your helmet like the real spartans... That would be really difficult and most of all very expensive. And I mean very very expensive.
     
  7. SuperFly1414

    SuperFly1414 New Member

    Thank you for this wonderful video!
     
    Last edited by a moderator: Jan 1, 2017
  8. Redshirt

    Redshirt

    I destroyed another servo. I could use some ideas . . . .

    Repost from 1 March:

    On my Spartan Laser I used an RC aircraft landing gear retract servo to retract and extend the shroud. To do so, I removed the electronics from the servo and wired the motor directly using a DPDT switch to control direction and a limit switch to cut off power. The limit switch has proved less than reliable, leading to a burnt out servo motor. Is there a SIMPLE way to pulse the new servo and get it to do its business as intended without me gutting it and having to rely on my analog cutoff?
    Someone suggested buying a servo tester and gutting it for this functionality, but I believe those are geared for calibrating standard servos, not testing retracts.


    EDIT 27 Mar: I ordered up a pair (plus a spare) of mini servo testers hoping I can set one to deliver an open pulse (pulse length well above neutral) when powered and the other to deliver a close pulse (Pulse length well above neutral) when powered. I'll keep the DPDT switch to power/depower the two circuits and drive the unmodified servo. Anyone with actual RC or robotics experience please tell me why this will or won't work. Any tips or pointers would be welcome.

    Redshirt
     
  9. thatdecade

    thatdecade Well-Known Member

    Wish I could help. I have used servos exactly once. I will say this on reversing the motion, shouldn't you be using an H-bridge to reverse the voltage to the motor?
     
  10. Redshirt

    Redshirt

    Thanks. I'm using a DPDT switch circuit to reverse direction and cutting power in one direction with a limit switch (raised) and cutting power in the lower position with the master power switch. I wiki'd H-Bridge, and believe that the DPDT meets the definition, but realize MOSFETs and other advanced tricks also meet the definition. I hope that by cannibalizing the two cheapie servo testers I can use the DPDT to send the distinct open and close signals to the servo via the signal wire and just wire the supply wires with constant power. I'll use an ammeter to make sure there's no draw at the limits to burn up the servo. Here's hoping it works . . . .

    Redshirt
     
  11. Biggus Dickus

    Biggus Dickus New Member

    If I have two fans in my helmet, should I have one blowing in and one blowing out, both blowing in or both blowing out?
     
  12. EVAkura

    EVAkura 405th Regiment Officer

    It depends on the configuration of your helmet and the placement of your fans. Use whichever one creates the best airflow. Generally, one in and one out works best, but that is not always the case.
     
  13. SniperWolf

    SniperWolf

    Anyone have suggestions for LED panels, or lights. Been looking into getting some in my suit, I'm just not sure what gives the look. Thanks in advanced.
     
  14. HaloGoddess

    HaloGoddess

  15. thatdecade

    thatdecade Well-Known Member

    Check the video in my signature, dollar store reading lights are easy to work with. Diffuse them with any plastic you can get your hands on.
    http://youtu.be/sWDNHmNvvmA

    A step up from that are pre-wired LED pigtails that you can purchase on eBay. A 12 volt prewired LED will run on a common 9 volt battery.
    http://www.ebay.com/itm/20-pcs-PRE-...Parts_Accessories&hash=item19eaff1aa3&vxp=mtr

    Lastly, the most hands on approach is a visit to radioshack or similar, and buy some LEDs, resisters, and battery clips. Then solder up the wiring to add to your suit. This thread has lots of discussion on what LEDs and resistor values to choose.
    http://www.405th.com/showthread.php/26853-quot-Help!-quot-for-Electronics?p=701054#post701054

    edit:
    Another eBay link. Pre wired LEDs, each with a 9volt battery clip. A little wasteful, as you can wire them yourself and run multiple LEDs on a single 9 volt battery. But this is a quick and dirty way to get your suit to light up.
    http://www.ebay.com/itm/25-PRE-WIRE...895?pt=LH_DefaultDomain_0&hash=item4ac114fc47
     
  16. thatdecade

    thatdecade Well-Known Member

    I know there is a stickies index, but those threads should also be sticked, for real ;)
     
  17. Denjus

    Denjus New Member

  18. thatdecade

    thatdecade Well-Known Member

    Assuming those are standard 12 volt LED strips. They actually have resistors built in. You can connect the 9 volt directly to the strip. Wire them in parallel to the 9 volt. You may need a second 9 volt to brighten the LEDs.
     
  19. wingedwolf111

    wingedwolf111 New Member

    hello i am making an halo assault rifle that i want to have an ammo counter on and i have some questions.

    Question 1 how do i program the ammo counter to go down with a trigger to make it go down and reset with a different button.

    question 2 i am wanting to use earth magnets so i can connect the gun to the armor just like they do in the games would this interfere with my electronics?
     
  20. thatdecade

    thatdecade Well-Known Member

    Magnets are safe around electronics. At most, they could potentially mess with the switches. Don't get them too close.

    For the ammo counter, look into arduino. It is inexpensive and beginner friendly. Once you have an arduino setup, here is some code I wrote for the ammo counter display.
    https://codebender.cc/sketch:14207
     
  21. RobTC

    RobTC

    wingedwolf111

    1) Buy a ready made ammo counter (here: http://www.westaby.net/store/index...._id=24&zenid=fcf206388eaf90f8f6f34758f15c8103 - you can get the AR "power" switch there too) or learn some super basic Arduino loops and I/O. That's the most specific advice I can give to a vague question.

    2) They shouldn't, but it's possible, particularly with magnets powerful enough to hold up a whole prop. You can use 1/8" sheet steel to shield the electronics from the magnets- the magnetic field lines follow the steel rather than spreading out normally and crossing the paths of the wiring. The worst that could happen is the magnets induce a pulse in the trigger line as you wave the gun past them and you get a false ammo count drop. It would take a much more powerful magnetic field (and faster motion than just holstering) to induce an electronics-frying current. So you don't really need to worry about it.
     
  22. recon313

    recon313 Jr Member

    Guys I was wondering which type of sander are better got sanding belt or random orbit sander or Palm sander ?
     
  23. Chernobyl

    Chernobyl

    Depends what you're using it for. Honestly, though - if you're putting on enough bondo to warrant the use of a mechanical sander, the chances are that you're putting too much on.

    For props, however, a palm sander might be better.
     
  24. recon313

    recon313 Jr Member

    Well I was planning to use it for rough sanding as I tend to coat my armor excessively(Yes I cut some of it using cutter but I let some a bit excess so that I don't have keep in case I cut it too low) i plan to use it form initial sanding rough sanding only. So it's the square palm sander is good for that?
     
  25. FlyinPhil

    FlyinPhil Marketplace Supervisor Division Staff

    You'll probably be better off with a set of rasps/files and a wire brush to clean them often. As far as body filler goes, if you are laying it on more than 1-2mm thick, you are putting on too much.
     

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