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.

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Hackaday Prize Entry: Fighting Dehydration One Sip At A Time

Humans don’t survive long without water, and most people walk around in a chronic state of mild dehydration even if they have access to plenty of drinking water. It’s hard to stay properly hydrated, and harder still to keep track of your intake, which is the idea behind this water-intake monitoring IoT drinking straw.

Dehydration is a particularly acute problem in the elderly, since the sense of thirst tends to diminish with age. [jflaschberger]’s Hackaday Prize entry seeks to automate the tedious and error-prone job of recording fluid intake, something that caregivers generally have to take care of by eyeballing that half-empty glass and guessing. The HydrObserve uses a tiny turbine flowmeter that can mount to a drinking straw or water bottle cap. A Hall sensor in the turbine sends flow data to a Cypress BLE SoC module, which totalizes the volume sipped and records a patient identifier. A caregiver can then scan the data from the HydrObserve at the end of the day for charting and to find out if anyone is behind on their fluids.

There are problems to solve, not least being the turbine, which doesn’t appear to be food safe. But that’s a small matter that shouldn’t stand in the way of an idea as good as this one. We’ve seen a lot of good entries in the Assistive Technology phase of the 2017 Hackaday Prize, like a walker that works on stairs or sonic glasses for the blind. There are only a couple of days left in this phase — got any bright ideas?

Fail Of The Week: Magnetic Flow Measurement Gone Wrong

Physics gives us the basic tools needed to understand the universe, but turning theory into something useful is how engineers make their living. Pushing on that boundary is the subject of this week’s Fail of the Week, wherein we follow the travails of making a working magnetic flowmeter (YouTube, embedded below).

Theory suggests that measuring fluid flow should be simple. After all, sticking a magnetic paddle wheel into a fluid stream and counting pulses with a reed switch or Hall sensor is pretty straightforward, right? In this case, though, [Grady] of Practical Engineering starts out with a much more complicated flow measurement modality – electromagnetic detection. He does a great job of explaining Faraday’s Law of Induction and how a fluid can be the conductor that moves through a magnetic field and has a measurable current induced in it. The current should be proportional to the velocity of the fluid, so it should be a snap to whip up a homebrew magnetic flowmeter, right? Nope – despite valiant effort, [Grady] was never able to get a usable signal out of the noise in his system. 

The theory is sound, his test rig looks workable, and he’s got some pretty decent instrumentation. So where did [Grady] go wrong? Could he clean up the signal with a better instrumentation amp? What would happen if he changed the process fluid to something more conductive, like salt water? By his own admission, electrical engineering is not his strong suit – he’s a civil engineer by trade. Think you can clean up that signal? Let us know in the comments section. 

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