Assess Your Output with a Cheap DIY Urine Flowmeter

Some things about the human body are trivial to measure. Height, weight, blood pressure, pulse, temperature — these are all easily quantifiable with the simplest of instruments and can provide valuable insights into our state of health. Electrical activity in the heart and the brain can be captured with more complex instruments, too, and all manner of scopes can be inserted into various orifices to obtain actionable information about what’s going on.

But what about, err, going? Urine flow can be an important leading indicator for a host of diseases and conditions, but it generally relies on subjective reports from the patient. Is there a way to objectively measure how well urine is flowing? Of course there is.

The goal for [GreenEyedExplorer]’s simple uroflowmeter is simple: provide a cheap, easy to use instrument that any patient can use to quantify the rate of urine flow while voiding. Now, we know what you’re thinking — isn’t liquid flow usually measured in a closed system with a paddlewheel or something extending into the stream? Wouldn’t such a device for urine flow either be invasive or messy, or both? Rest assured, this technique is simple and tidy. A small load cell is attached to an ESP8266 through an HX711 load cell amp. A small pan on the load cell receives urine while voiding, and the force of the urine striking the pan is assessed by the software. Reports can be printed to share with your doctor, and records are kept to see how flow changes over time.

All kidding aside, this could be an important diagnostic tool, and at 10€ to build, it empowers anyone to take charge of their health. And since [GreenEyedExplorer] is actually a urologist, we’re taking this one seriously.

[via r/esp8266]

33 thoughts on “Assess Your Output with a Cheap DIY Urine Flowmeter

  1. Unfortunately this devices primary competitor is a jug. And it looses to it.

    If you really want to categorise BPH then you don’t want a subjective scale you probably want a subjective one.

    There is no point telling a one one they are excreting fine when they are complaining about going to often or being woken with a need to go.

    This is mostly useful for non invasive urine output measurement where flow doesn’t matter. Say to avoid a catheter but have an idea of volume error hour per unit weight.

          1. Flow rate can be very important in diagnosing prostate, bladder, drug interactions, & kidney issues.
            Frequency and volume is just flow rate averaged out over the day, auditing the whole filter system rather than just the output plumbing.

    1. Actually I think the subjective view is exactly what’s needed. Everybody is different in terms of what their usual flow rate is, and regular use of this device will help to establish a baseline in the user’s flow from which ocassional deviations will stand out, and be able to be interpreted as signals of an underlying malaise.

      The big issue would be in normalising the timing of the tests with respect to general hydration levels, exercise and even diet; we all know how much more equine our flow is after a heavy night for example, and depending on what is eaten more water may be excreted through stools than usually passes out as urine. Exercise might lead to more being sweated out.

      If you have a regular schedule though, and a predictable diet, uing this system correctly could be quite interesting.

      Also yeah – all a jug would tell you is how much you peed – not how quickly the jug filled; this device could tell you (assuming the code took regular measurements, tbh I’ve not watched the vids) how the basin filled against time, adding a whole dimension to the jug’s ouput…

      1. Yeah I 100% agree with you I replied to explain autocorrect butchered one or two sentences there.

        We need a subjective view and this is also reflected in the NICE (National institute for Clinical Excellence) guidance I linked above.

        It makes it clear what we want to know is all subjective.

        How often are you going to pee (keep a diary), how much do you pass when you go. Does it dribble, do you struggle to get going and do you need to go back soon after.

        Once objective measures are needed you already have a specialist with a tune up your waazoo who will see there and then.

        As engineers we think objective measurement is king but in the medical field telling someone objectively there is nothing wrong with them when they have a complaint is the best way to get a black eye and a law suit,.

    2. I think you all misunderstood the point of this device. The objective is not to determine volume or time, but the force exerted by the flow. Yes, you can calculate the first two with a device such as this, if you also measure and input the final volume (which this device can not measure itself), and from that determine flow rate, but that isn’t the purpose of this device. An increase or decrease in the force exerted when voiding can be indicative of a number of conditions.

    1. If he just weights himself then this would give a different result because:
      A: He is also losing weight by sweating, because he is worried how accurate the reading will be.
      B: This would include any pee that missed the toiled due to bad aiming.

    2. Because he’s not concerned with how much pee is evacuated, he’s concerned with how fast it’s evacuated.
      Or the flow rate is the most important, I’m sure the volume is also being recorded but it’s not the focus. Getting a 150kg max scale that has gram accuracy is going to be expensive, getting a graduated sample bottle / measuring cup is cheap.

  2. Anyone else think the 1kg sensor might get pushed beyond its limit in some cases? I remember in one of the Mythbusters episodes, Kari managed to pee 1.5L all at once. Pretty sure urine is slightly more dense than pure water so that translates to a little more than 1.5kg. And then there’s the weight of the container.

    1. Salt content, along with other minerals make urine heavier than regular water.
      Even though urine is warmer (by comparison) to the water in the toilet bowl, it sinks to the bottom instead of rising to the surface. Water water will rise to the surface of cold water, unless it is a solution that makes it denser than the cold water.

  3. Summa’biotch! Dr. Rok Rodic IS really a Urologist in Slovenia (aka Yugoslavia back in the old days).
    http://www.uroweb.si/index.php?menu=aboutus

    FLOW is important for prostate problems and kidney stone blockage. Rok is really into inventing and electronics. He has a 3D printer. He could make a mini-paddle-wheel attached to a DC PM motor which acts like a wind anemometer. Insert the whole thing into a 1″ (2.54 cm) or larger PVC tube. That’s a subjective measurement depending on male girth (ugh). You also have to rinse it out with warm water after every use. A mild disinfectant spray like Lysol would be good too.

    I can’t see why a photo cell and laser arrangement couldn’t measure liquid flow rate too.

  4. I’ve (unfortunately) had a fair bit of experience with uroflowmetry. The expensive devices used by my local urology department consist of a jug on a load cell, with a large funnel to receive the urine. At the bottom of the funnel is a motor-driven wheel that seems to be there to make the urine fly outwards and hit the side of the jug instead of falling down to the bottom. There’s a Bluetooth interface to a unit with a display, keypad and thermal printer.

    For many conditions they’re interested in both the flow rate (especially peak flow) and the shape of the graph of flow rate.

  5. Hi Guys
    I was happy to find this project and discussion. We make an android/iPhone app (free) to do this! it’s called “Uroflow tracings”. It uses the sound of the urine stream hitting the water in a toilet, so it’s a no-hardware at-home and is aimed at answering the question “is it worse now than six months ago?”

    What led me here though, is an interest in measuring the urine output of a paraplegic in a wheelchair with a catheter. The idea is that with no sensation the patient does not know that the catheter has developed a kink, or got blocked or slipped out through the sphincter. When this happens no urine gets out and the bladder eventually becomes distended which causes an increase of BP and sweating and headache, very serious and getting worse until relieved. Since there is no response to these signs (the urine cannot escape the bladder) the signs get worse. (It’s called Autonomic Dysreflexia).
    One approach is to weigh the urine bag and send the weight to ….. where it can trigger action in the caregiver.

  6. Hi.
    I am glad to see response to my uroflowmetry device. By now many devices are up and running. Most of them are made in less developed countries, which was my intention. So, please report to me if there are any new machines made… At the time of writting this post the support for ESP8266 has been discontinued due to low RAM and computing power.
    I have even made the third video in the series.

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