Designing 8 Channel Solenoid Driver For Projector

Discussion in 'The Lounge' started by markerney, Mar 8, 2009.

  1. markerney

    markerney New Member

    I am not an expert by far (I'm a beginner) and I'm seeking help in designing a relativly simple driver circuit to drive (8) Ledex 24 volt solenoids. They draw right at 500ma each but I would like to pretend they are 1 Amp to OVER BUILD the circuit so we account for overlap and feedback voltage (I want to build it so it will last without failure). I would like to be able to control the gate with a 5 volt TTL trigger. To be more specific it is to control (8) solenoids that will have mirrors mounted to each one to reflect a laser beam when actuated. The physical switch will be (8) lever arm micro switches that you can tap with your fingers to the beat of music. The reason I want to use a 5 volt TTL trigger is so I can record the trigger on different tracks of a MODIFIED Alesis ADAT recorder and sync them to music and then play them back. Does anybody have an idea of what the best FET I can use for this application would be and how to trigger it using a 5 volt TTL signal? What value diode should I use to protect the FET from the feedback? I would even be willing to pay for some assistance in the design of a circuit! My intention is to use 2 brand new regulated power supplies. If I use a seperate 5 volt regulated power supply for the TTL trigger and a seperate 24 volt regulated power supply for the solenoids load .... does the FET, solenoid and trigger transistor have to share BOTH GROUNDS? If yes .... how do I do this? ANY SCHEMATICS WOULD BE GREATLY APPRECIATED! Thank you sincerely for your time and consideration. Mark Erney

    I forgot to mention the duty cycle I will be using. (4) of the solenoids will need to be actuated continuous ON for up to 5 or 10 minutes duration and the other (4) solenoids will operate intermitant ON and OFF for bouncing beams. The circuit has to be able to handle all (8) actuated at one time and have the ability to work in a WARM atmosphere. Do you think a 6 to 8 Amp 24v regulated power supply is enough?

    DOES ANYBODY KNOW WHO I CAN PAY TO DESIGN THIS CIRCUIT FOR ME? I can breadboard it and build it, I just need the design help. I do not have enough experience to do the calculations necessary for a professional quality driver with some safety features so all the work is not wasted. There is nothing like the smell of BURNT transistors in the morning! Thank you again for your time and consideration. Really looking forward to hearing from the SOLENOID DRIVER GURU!
  2. aly

    aly Well-Known Member

    It would be better to post this message to an Electronics forum, but I anyway, I can help you.
    You do not need FET transistors (which you can easily damage with static electricity), simple Bipolar would do fine. You need to make an "open-collector" circuit, which is the most widely used circuit in electronics world. See the schematic:
    and the complete page HERE.

    You can use virtualy any NPN transistor, that can sink 1A of current.
    See this LIST of transistors.

    Then just multiply the number of this cirtuit for 8 times, the number of solenoids.

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