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Programmable timer / usb pump

Discussion in 'General Electronics Discussion' started by SimonDwyer, Dec 28, 2015.

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  1. SimonDwyer


    Dec 28, 2015

    Im pretty amateur with this kinda thing as you'll learn, and not sure if this is the right place to post this, but we'll see how we go.

    I'm wanting to power a 5v usb submersible pump using a rechargeable usb power bank (firstly: will this work?), then I want to wire a programmable timer into the cable to run the pump at certain intervals for a certain period. Ideally the timer would be powered by the same source, but if not possible then by AA batteries.

    Is there an assembled 'product' that I can use for this? If so can someone point me in the right direction to source this?

    So far my googling has failed, so thought I'd try this!

  2. donkey


    Feb 26, 2011
    ok I am going to ask some questions here as well as answer some
    if you find a 5 volt pump then yes it will work of USB... however pumps and motors are usually pretty good at sucking current so expect to replace batteries... often
    secondly yes you can find a 5 volt timer
    as for assembled, most likely not now for the questions
    why the heck would you want a 5volt pump anyways? I could possibly find you a 12volt one and they can run on solar with battery back up.
    also when you say programmable.... how long? do you want it to turn on and off every3 seconds or everyday? this is vastly different.
    lastly why does an amateur want to start with a water project? have you never heard electricity and water don't mix? if for example you use a lipo pack for your batteries, and somehow water gets into them.... have you ever seen fire in water? there is a chance you will... as well as polluting the water with lithium.... but that's for another time.

    I hate being mean... and don't go into the off topic area where I posted recently about me being mean lol.
    I am newbie ish myself but I recommend you break down what you need.
    first and foremost is the pump.... does it have to be 5volt?
    secondly the timer, how long a period is it on for? would a float switch be better(if you are filling a container for example)
    the more detail on a project you give the more insight the lovely people here can offer. I wish you the best on this project
  3. SimonDwyer


    Dec 28, 2015

    Thanks for your reply.
    It's for a drip feed hydroponics setup.

    5v pump because it is cheap and compact, and already has the usb connector - I think they're designed for a desktop aquarium or something?

    The pump is submersible with a 1.5m cable, the battery would be separate from the reservoir, so not too worried about the battery getting wet.

    The timer would need to run possibly every hour for 5 mins, but I need to be able to adjust this if it is not suitable.

    The reason for using a small usb pump is low cost and compactness, I want it to be as stand alone and portable as possible. But obviously if it won't work then a 12v would be the next option, however things would become a bit bulkier and expensive I imagine.

    The battery pack has a built in solar panel, so ideally because the motor won't be running all the time, the battery will have enough time to recharge itself in between. But I imagine because it's cheap, it will also be crap, so this might not work.

    The programmable switch is the bit I can't find tho..

  4. AnalogKid


    Jun 10, 2015
    Your overall plan is sound, but the real world might not play along. The problem with a 5V programmable timer is that most of them have digital displays, and consume power continuously even when the output is energized only 10% of the time. They do not use the custom chips in digital watches that can run for 10 years on one battery. A circuit using standard Chips would be low power enough, but it sounds like you don't want to build a circuit. Shop on ebay for a small cycle timer pc board assembly that has trimpots for adjustments rather than a digital display, and the power drain might be low enough.

    What are the voltage and amp-hour ratings for the battery, and what are the ratings for the solar panel?

  5. SimonDwyer


    Dec 28, 2015
    Hey ak,

    Here are the specs of the battery/solar panel.

    1.Output Voltage: DC 5.5V
    3.Input Voltage/Current:5.0~5.5V
    4.Battery Capacity: 3.7v/5000mAh
    5.Solar PV Panel: 5.5V 300mA 1.5W
    6.Solar conversing rate: 10~11%

    It's not that I don't want to build a circuit, it's more that wiring a relay into a cable is about the extent of my ability! ... But I suppose, gotta try to learn.

  6. Bluejets


    Oct 5, 2014
    I built a pump control using an Arduino Pro Mini, an LDR to detect night and day for different pump run times, plug pack for power (could be solar) and a relay for interfacing to a small 240v submersible pump.
    Also has a switch to use short on/off times as a "test" to make sure "night" and "day" are working properly.
    Uses delays in the program which is sometimes frowned upon but in this instance it is a good thing.
    As the LDR switches from night to day or visa versa, the current times are allowed to time out before switching over.
    Current comsumption was never an issue for me.
  7. Alec_t


    Jul 7, 2015
    Your lithium battery will require a control circuit for charging/discharging it safely, to prevent the battery catching fire or exploding.
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