Relay for a 6V toy battery to 9V switch

Discussion in 'The Projects Forum' started by jpardue, Feb 28, 2015.

  1. jpardue

    Thread Starter New Member

    Feb 28, 2015
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    0
    Hi all - apologies if this has already been asked, but i am no expert and despite looking around was not able to find an answer. i have a special needs little girl who uses an Ablenet Big Mack switch to communicate; this button has an output so that when you hit a big button it can activate a toy. I plugged in a mono audio jack and then spliced the other end into a power wheel. So no when she hits her button while sitting in the car, the car will go. this worked initially but then stopped because i think it fried the switch (which are very expensive). after reading around, i believe that the problem is likely that the current from the car battery was too much for the special needs switch which takes a 9 volt battery. i am trying to buy a relay to put between the car and switch, but i dont know how to do this or what to buy. is this the right direction, and if so, does anyone know what type of relay that i should buy? please see below for information on the parts that i am using

    special needs button: https://www.enablemart.com/bigmack-communicator?gclid=CPzO5oXHhcQCFUMjgQodthcABA

    power wheel: http://www.walmart.com/ip/26094901?...34824832&wl4=&wl5=pla&wl6=78294790592&veh=sem

    end product: http://www.udel.edu/gobabygo/
     
  2. Marcus2012

    Member

    Feb 22, 2015
    349
    26
    Hi
    I was just wondering how did you initially bypass the control switch on the wheel because the control terminals of these toys are usually isolated from the large currents drawn by the motor/s. I am assuming as it is one speed there is a "go" switch on the cars wheel somewhere. I would think this is connected to a control circuit rather than directly to the motor but it may be. Either as long as it is a SPST or SPDT switch you can replace it with a relay. You might be able to get away with a 12V car relay but I am not entirely sure if the 9V supply would flip it, it might but if not you may need a 9V one which you can get off ebay but check the max current rating is ok for the cars battery (or whatever circuit current it is carrying). Relay are very simple to connect up I have attached a diagram (you could put a mono jack socket on the coil input as well so you can unplug the switch when you like).

    Few more things though

    1) Test the mono output of the switch to see if its ok, it should be I cannot see the car conducting that current through a switch a child presses on the wheel but it may.
    2)Check the car without the mods to make sure that's ok in its factory setup (you were using 9V to switch a 6V circuit).

    Links to relays

    Car relay http://www.ebay.com/itm/Sales-Hot-C...Parts_Accessories&hash=item33968683f5&vxp=mtr
    9V 5A relay http://www.ebay.com/itm/5pcs-Power-...953?pt=LH_DefaultDomain_0&hash=item234ad08d19
     
  3. Marcus2012

    Member

    Feb 22, 2015
    349
    26
    Oh I should have asked about the mono output from the SN switch. Is it a power supply essentially (1 terminal +9V, 1 terminal 0V) or is it just a conduit for its application in another circuit.
     
  4. jpardue

    Thread Starter New Member

    Feb 28, 2015
    3
    0
    Hi - thanks so much for your response. It is very helpful. First - I think you are right, i should have connected into the smaller isolated wires instead of the wire coming from the battery. those are slightly thinner which was probably my initial mistake. I might not need a relay then if reconnect to the smaller wires, correct? also, i think the switch requires the toy connected to the output to have its own power source; in other words, i believe it just triggers a battery powered toy and isnt able to power something itself. Again, thank you very much for your insight and help.
     
  5. Marcus2012

    Member

    Feb 22, 2015
    349
    26
    Hey glad that helped :)

    Ok then if we work on the assumption that the SN switch does just close a circuit for another device then yeah I would imagine you'd be ok just bypassing the control switch in the wheel. Open the wheel up and check the current across the switch when the motor drives, it should be nice and low, on the order of milliamps if its just a control circuit. Do you know what the SN switch function is rated for? Just so you can be safe, they did indeed look expensive! If this is the case then bypass it with each mono lead just connected to the wheel switch terminals in parallel (maybe add a mono jack socket on the wheel), no need to remove the original wheel switch.

    Good luck and let me know if you need more help :)
     
  6. jpardue

    Thread Starter New Member

    Feb 28, 2015
    3
    0
    Makes perfect sense; thanks again!
     
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