The Association of Model Submariners.

Would you like to react to this message? Create an account in a few clicks or log in to continue.

* THE FORUM FOR ALL THOSE INTERESTED IN BUILDING AND OPERATING MODEL SUBMARINES *



Join the AMS - Registered Forum users can become members of the AMS and it's free ...... To join send an email with your name , address and phone number to amstreasure@googlemail.com


For a guide to past events see the "Shows and Events" section.

....


,

"***"

Who is online?

In total there is 1 user online :: 0 Registered, 0 Hidden and 1 Guest

None


Most users ever online was 180 on Tue Nov 05, 2019 6:03 am

Latest topics

» 915mhz / 868mhz as a viable frequency for submarines.
Transmission of servo (pwm) signals through water and clear plastic EmptyWed Feb 01, 2023 8:15 am by maxx78

» 27Mhz - Radio Ideas
Transmission of servo (pwm) signals through water and clear plastic EmptyTue Jan 31, 2023 8:39 am by david f

» Not the hobby I expected :)
Transmission of servo (pwm) signals through water and clear plastic EmptyMon Dec 12, 2022 9:07 pm by cat

» Upholder build instructions
Transmission of servo (pwm) signals through water and clear plastic EmptySun Dec 11, 2022 5:57 am by lenD

» Antennas - Underwater
Transmission of servo (pwm) signals through water and clear plastic EmptyFri Dec 09, 2022 9:50 am by david f

» Single Channel Remote for submarines
Transmission of servo (pwm) signals through water and clear plastic EmptyFri Dec 02, 2022 2:59 pm by david f

» self contained compressor and solenoid valve for bladder systems.
Transmission of servo (pwm) signals through water and clear plastic EmptyThu Nov 24, 2022 5:58 pm by geofrancis

» New to this forum and first submarine
Transmission of servo (pwm) signals through water and clear plastic EmptyFri Oct 14, 2022 6:15 pm by Tom(ADMIN)

» USS Bluefish
Transmission of servo (pwm) signals through water and clear plastic EmptyFri Oct 14, 2022 1:52 am by Cheapsub

Statistics

Our users have posted a total of 11829 messages in 1937 subjects

We have 971 registered users

The newest registered user is DAKpy

2 posters

    Transmission of servo (pwm) signals through water and clear plastic

    david f
    david f
    AMS Treasurer


    Posts : 2293
    Join date : 2010-11-10
    Age : 72
    Location : Cumbria

    Transmission of servo (pwm) signals through water and clear plastic Empty Transmission of servo (pwm) signals through water and clear plastic

    Post  david f Sat Jul 05, 2014 12:43 pm

    I am just putting the components away for something I was trying with the original Darnell XXI. I originally needed to send a servo signal through a clear, flat plastic hatch. I dropped the idea later as you will see in the Darnell XXI thread.

    But the method I tried worked well and was very simple.

    The sender unit (connected to the receiver) was just an Infrared LED with a 30 ohm resistor in series (just to limit the current. The receiver unit (connected to the servo) was a photodiode with a 1 megohm resistor in series. (The LED and photodiode were a matched pair but I can't remember where I bought them from. Ebay probably.)

    The early trials were surprisingly successful with the signal being happily beamed through several mm of plastic or even water.

    If you used a separate 5v supply at the receiver end then that is just one wire to transmit a servo signal.

    David

    salmon
    salmon
    AMS Forum Owner


    Posts : 312
    Join date : 2011-09-02
    Age : 63
    Location : Las Vegas, Nevada - USA

    Transmission of servo (pwm) signals through water and clear plastic Empty Re: Transmission of servo (pwm) signals through water and clear plastic

    Post  salmon Sun Jul 06, 2014 7:35 pm

    Is that all it took was a resistor connected directly to the infrared led? No complicated circuits? Am misunderstanding?
    Thank you for posting this! Makes the brain work.


    _________________
    If you can cut, drill, saw, hit things and swear a lot, you're well on the way to building a working model sub.
    david f
    david f
    AMS Treasurer


    Posts : 2293
    Join date : 2010-11-10
    Age : 72
    Location : Cumbria

    Transmission of servo (pwm) signals through water and clear plastic Empty Re: Transmission of servo (pwm) signals through water and clear plastic

    Post  david f Mon Jul 07, 2014 2:40 pm

    Yes, it really is that simple. I've just connected it up again to remind myself.

    One side of the photodiode (the side without a flat on it) is connected to +5v.
    The other side of the photodiode is connected to the white signal wire of the servo and one end of the 1 megohm resistor. The other side of the resistor goes to earth. (It's a pull-down resistor.)

    To "connect" the signal wire you would just need to push the led and diode into the end of ,say, some silicone tube.

    It should have wide application to model subs but, in my case, I bunged everything in a single WTC so the need for it disappeared!

    It is not particularly original - I'd seen the idea somewhere on the web in connection with robotics perhaps as an "optoisolator". The real optoisolaters are no good to us because they are encapsulated in a single device.

    David
    salmon
    salmon
    AMS Forum Owner


    Posts : 312
    Join date : 2011-09-02
    Age : 63
    Location : Las Vegas, Nevada - USA

    Transmission of servo (pwm) signals through water and clear plastic Empty Re: Transmission of servo (pwm) signals through water and clear plastic

    Post  salmon Mon Jul 07, 2014 3:01 pm

    Thank you David! I have heard that running a servo a long distance from the receiver causes problem with interference. This might be good for keeping a servo in a remote location on the sub. Definitely something to play with!


    _________________
    If you can cut, drill, saw, hit things and swear a lot, you're well on the way to building a working model sub.
    david f
    david f
    AMS Treasurer


    Posts : 2293
    Join date : 2010-11-10
    Age : 72
    Location : Cumbria

    Transmission of servo (pwm) signals through water and clear plastic Empty Re: Transmission of servo (pwm) signals through water and clear plastic

    Post  david f Mon Jul 07, 2014 4:18 pm

    Your comment has made me think of something else.
    Long servo leads can indeed give interference. I wonder if the light signal can go down a fibre optic cable?

    David
    salmon
    salmon
    AMS Forum Owner


    Posts : 312
    Join date : 2011-09-02
    Age : 63
    Location : Las Vegas, Nevada - USA

    Transmission of servo (pwm) signals through water and clear plastic Empty Re: Transmission of servo (pwm) signals through water and clear plastic

    Post  salmon Tue Jul 08, 2014 12:29 am

    Exactly what I was thinking!


    _________________
    If you can cut, drill, saw, hit things and swear a lot, you're well on the way to building a working model sub.

      Current date/time is Fri Feb 03, 2023 10:57 pm