In previous posts, I have detailed how I keep track of the status of my stand by generator. One of the main tasks of the stand by generator is to ensure that there is a steady supply of power for the sump pump. So, wouldn’t it be nice if we could monitor the level of the sump, preferably remotely, so we can take action if it is too high?
Raspberry Pi to the rescue. In the course of investigating distance sensors, I came across. It explains the use of the ultrasonic distance sensor HY-SRF05, which can read distances between 5cm and 2m. Perfect for my purpose. Besides, they only cost around $3.00 each!
I took the very simple voltage divider circuit mentioned on that webpage and created a little circuit board for it. Here’s it is, fresh out of the etcher, with the ink of hand drawn traces still covering the only copper left on the board. To the top you can see the 4 points of the board to which the HY-SRF05 will be attached by solder points.
Once I sanded the ink off, drilled the holes and mounted the resistors, connecting wires and sensor, I did a test. It worked! Woohoo! Next, accuracy testing was conducted, proving that most of the time the reading is within 5%. Good enough for my purpose.
To attach the sensor in a convenient spot, I used a hose clamp and short piece of wire strapping. Through experimenting I found out that in order to get a fairly accurate reading, you need to get as much clearance on the sides of the sensor as possible. The wire strapping allows for this, as it is bendable and strong enough to support the lightweight sensor. The sensor and circuit board are kept in place with a colourful binder clip, for easy removal in case the pump needs to be serviced.
The Raspberry Pi itself is mounted some distance away (+/- 50 cm) on the sump pump closet wall, using a case I obtained from Allied Electronics. A couple of screws inserted in the drywall keep the Pi high and dry.
I took the very simple voltage divider circuit mentioned on that webpage and created a little circuit board for it. Here’s it is, fresh out of the etcher, with the ink of hand drawn traces still covering the only copper left on the board. To the top you can see the 4 points of the board to which the HY-SRF05 will be attached by solder points.
Once I sanded the ink off, drilled the holes and mounted the resistors, connecting wires and sensor, I did a test. It worked! Woohoo! Next, accuracy testing was conducted, proving that most of the time the reading is within 5%. Good enough for my purpose.
To attach the sensor in a convenient spot, I used a hose clamp and short piece of wire strapping. Through experimenting I found out that in order to get a fairly accurate reading, you need to get as much clearance on the sides of the sensor as possible. The wire strapping allows for this, as it is bendable and strong enough to support the lightweight sensor. The sensor and circuit board are kept in place with a colourful binder clip, for easy removal in case the pump needs to be serviced.
The Raspberry Pi itself is mounted some distance away (+/- 50 cm) on the sump pump closet wall, using a case I obtained from Allied Electronics. A couple of screws inserted in the drywall keep the Pi high and dry.
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