Episode: 3217
Title: HPR3217: Sump Minion
Source: https://hub.hackerpublicradio.org/ccdn.php?filename=/eps/hpr3217/hpr3217.mp3
Transcribed: 2025-10-24 18:59:31

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This is Hacker Public Radio Episode 3217 for Tuesday 1 December 2020.
Today's show is entitled Some Million and In Part on the Series,
Hobby Electronics. It is hosted by Brian in Ohio and in about 18 minutes long
and Karina Clean Flag. The summer is my first internet on things device without using Python.
This episode of HBR is brought to you by AnanasThost.com.
Get 15% discount on all shared hosting with the offer code HBR15.
That's HBR15. Better web hosting that's honest and fair at AnanasThost.com.
Hello Hacker Public Radio. Brian in Ohio here back. I'm out from under my rock.
I'm back in Northwest Ohio using my regular voice and although it was kind of fun doing that
eSpeak episode, eSpeak's pretty cool. It's actually very fast as type up what you want to say
and have eSpeak read it out for you and I don't understand why nobody would complain about the
audio. It's no worse than operators episodes and we all love his shows don't we?
Anyway, I wanted to talk a little bit about a problem that I had here at my house that I found a
solution to and I thought it might be interesting to you all. Okay, the problem is is that here in
Northwest Ohio I we live in a place where with a very high water table we live in an area that
used to be called the Great Black Swamp was we're basically on the shores of the the great lakes
here in the US. It's the largest source of fresh water in the planet I believe and we because of
that you can just dig down a little bit not very far and hit water and so if you have a basement
in your house you're going to have water issues. To correct that problem houses here in this area
have a sump's put in and a sump and I've got a couple of pictures here the sump consists of a
a basin that's in your basement and there's some piping that that directs the water from outside
into this sump collection area and then that water is pumped out usually done pumped out by an
electrical pump and a good sump system has some kind of backup usually has two pumps in it so my
sump system has the picture one or is just kind of looking into the the closet where it sits
and then picture two is looking down into the sump with the cover off and you see the
the pump it's the main pump is the black device with the green on top and there's a secondary pump
that is the the secondary pump is the black part that's got a hose clamp around it with a
little white knob thing that's that's connected to this there's a PVC pipe with a wire that runs
down to it and so those are the two pumps in my sump system the the real problem isn't necessarily
the sump the sump itself it's one the sump pumps fail and so the primary pump can fail in many
ways of course it can have mechanical failure it's a it's a pump sitting in water so rust is a
problem a lot of these pumps have some kind of float system that turns the pump off and on those
flump those floats can get stuck they can have sediment get into them and mess them up and of
course if you have some kind of electrical outage you can have your sump won't work if it's a
because it's powered by electric and so if you have a thunderstorm that knocks out the power
and there's water rising you won't have their your primary pump will not work that so I have a
secondary pump those can be different flavors some of them are electrical also but usually
those have a battery backup and those all of all of the secondary pumps have the same problem they
can fail in different ways mechanically but secondary pump that relies on some kind of battery if
there's a long power outage you might have to at least recharge that battery it might run into
problems there my secondary pump actually uses a city water as a mechanism to run a turbine to
draw the water out so if there's an assumption here that if your power is out and your city
water is out you're probably experiencing the zombie apocalypse and you've got other bigger
problems than your sump pump at that point or your sump it's in general so I wanted a system
I've had a couple of of floodings of the basement for a variety a couple of different reasons
so I wanted a system that would notify me when the water level in the sump was rising
and I wanted it set so that though when the water level hits where the secondary system kicks in
I would get that notification and I wanted a system that wouldn't use some kind of home
spy system that's available from one of your friendly corporations out there and I really didn't
want to use Python because I don't really know Python and I didn't want to just install
Python libraries and for a solution I wanted to be able to do it with tools that I understood
so the solution I came up with uses a raspberry pie a simple transistor circuit a C library that
allows me access to the pies GPIO pins those are the general purpose input and output pins and
those are those that header of 40 pin for number 26 pins I think it is I'm not sure what the
number is the little pins that stick out out of the the raspberry pies that allow those live
access to hook things up to them and I use the male client and some bash scripting in a cron
job to get this job done so here's how I did it I use a raspberry thrive the raspberry pie 3B
that's what I had laying around I installed of course slackware because that is the best operating
system excuse me that's the best Linux distribution that's out there and I used the Sarpy projects
the slackware arm on the raspberry pie I've got links in the show notes for these things
there's actually their developers of the slackware arm fork of the or part of the slackware project
they have a podcast I'm going to link to that they've got about 15 shows out pretty good listening
and so after installing slackware on my raspberry pie I wanted access to those general
purpose input output pins and initially I was a little bit of looking around and there's a way
to control this pins using calls to sysfs that are really just echoing into sysfs a virtual file
system that that creates these connections to these input now put pins from the kernel to the
real world and but unfortunately that sysfs system is deprecated as a link in the show note to
to what's happening there and it's being replaced by I think it's called live GPIO so I tried
to compile that and get it working and I and I could not do it so I was a little bit frustrated
at that point there's some other solutions of course is using python which I really don't want to
use there's a project called wiring pie which kind of makes the access to the GPIO pins very
similar to the way Arduino or wiring does it and it's but unfortunately that project's dead it
seems like and then there's a project out there called pie GPIOD it's it's still active there's
a slack builds for it I've got the slack builds is the official unofficial extra repository for
slackware users and a great source of software out there and they had a slack builds for it so I
built it up installed it into my pie and then had access to the to the GPIOs and that library is
actually pretty amazing it allows access from the c c functions it allows it has a python
wrapper and it has a bash commands that allow you access to the GPIOs it was very cool very easy
to install the the syntax of the commands are as kind of yeah I'd I'd have written it differently
but I I'm not complaining I'm just saying that's what I would do if I designed it but I'm not
going to change it works just fine the circuit I used a rework of a circuit that forced mims I
have a bunch of forest mims books in my library and if you don't know who forest mims is I've got
a link to a Wikipedia article in the show notes and he's put out a bunch of radio shack here in
the usway in this this this retailer radio shack where you get electronic stuff when I was growing
up and some one of the things they had was these little engineers notebooks and they were in graph
paper form and that circuits and stuff and just endless hours as a kid of looking at those and
dreaming about making things that really didn't come into fruition till now when I'm an older guy
but anyway so there's a forest mims has a circuit that involves a transistor a couple of
three resistors and it allows you to detect water pretty easily and so I've got a picture of that
circuit and that and I did it and try to do it in forest mims style graph paper and it gives
a kind of a block overview the circuits to the right and then what I would my main the main
change that I did was I installed a relay board and I'll describe how I did this later in the show
this relay board allows me to do a functional test of the system whenever I want to by
by basically shorting across the probe pins and then the system runs and it does what it's going
to do which I'll describe what it does when I get there so that's the third picture
now too as far as notification goes I remember that you can send text messages via emails and so
what I there's a link in the show note for different systems for different carriers
for for my carrier Verizon it's your phone number at vtex.com is who you would email to
and it comes up as a text message and so the best text messaging system for Raspberry Pi on the
command line is mutt so I set up a mutt client and I've got a link to on how I did that to my gmail
account and that is how I am notified if there's a problem in my sump it the system detects when the
water gets high through the circuit if it's if the water is you know shorted out the the probe
pins and the circuit goes to a logic level zero because it's driven low then a a mutt message is
said to my my phone letting me know that there's a problem that this water is coming up and then I
can go investigate to see what's going on so and so the script that I came up with that I
run on a cron job every minute it basically it has a few parts the first part is daily at six
a.m. it sends me a message just to let me know that that that pie is still running that that
Raspberry Pi is working that the GPIO Damon the PI GPIO D Damon which is what's running in the
background on on the on the Raspberry Pi is is still running if not it sends me a message because
only only root can start that Damon up so I would have to intervene SSH into that into that Raspberry
Pi and restarted it for some reason it died it makes sure that the the pins that I use which are
pin four and pins 17 on the on the Raspberry Pi the pin four is the input pin from the sensor the
pin 17 is the output to the relay which turns the relay off and on when I want it and make sure
those are correctly set up as input and output and if those two since at six a.m. if those two
those three things those the two pins and the Damon is running it sends me a message it says
that the system is running and then once a month I picked the first Wednesday of the month at noon
using those using a little bit of cut commands against date and it the system runs a monthly test
sends me a message that it's going to run a monthly test it basically energizes that relay short
shorting the pins of the probe the water probe and then makes and then the the circuit thinks that
the water is risen the the input to the GPIO goes from a logic high because the pin is held high
normally it's driven low and it's detected and I get a water running mess water rising message
does that once a month and then then the last part of the of the script is just the nor just
what the main purpose of this project is is this checks to see that the sensor pin is not not
at a logic zero driven low it says if it's a zero then the water is risen that that circuit is
active and it sends me a message that the water is rising but usually hope you know everything's
going well it would be a one and I don't get anything
so I first put this the
a breadboarded up the circuit I put in all and that's a picture picture for there the raspberry pie
with all the wires a big old mess of wires there to run the system and did a bunch of testing got
the script working and and then once I was confident that would work I made a strip board which is
picture five where a couple little headers ones to the to the right on the picture that's a
transistor in the resistors are on top and then on the left is the is where the wires that connect
to the to the some pump and to the relay board are put in and then the the header that's to the
right on the picture facing down is what plugs into the raspberry pie and then I had a case I
did a little cutting and pasting and I stuck that relay board onto the top of the case and secured
the whole thing into a two by four in the some closet and that's where the where my some minion
lives and hopefully I'll never have another water problem again that would require a flooding of
my basement for me that I could be able to intervene before I get a flooding problem and that's the
hope and right now I feel confident that that's what this device will do for me so in conclusion it
was a fun project I think it shows the power of Linux and floss there's so many different ways to
approach a problem and different solutions out there this is a solution I I chose and certainly
it's not a static problem it's something that I can tinker with and if I find new and better
ways to do it that's what I'll do it I'll implement those changes so anyway I hope it inspires you
to take one of those raspberry pies and and hook things up to the physical world and and make things move
well that's in the show if you have any comments go ahead and email me or post a comment or better
yet make your show for HPR telling us about how you solve the problem like this or just anything
that's a raspberry pie related would be interesting to hear all right enough of that Brian and
Hynes signing off and I want to remind everybody to go fast take chances
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