Aquaponics systems need a good water quality, and one of the parameters is pH value, which needs to be within a certain range in order for the fish and plants to thrive. This is of course also true for fish-only aquariums, but since I have an aquaponics system set up already, this is what I`ll focus on. There are a few pictures of the system in th
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is blog post: Debian on NSLU2 With USB Hard Disk and Homeplug Network (I`m using a Debian NSLU2 but it should be possible to use an Unslung NSLU2 too). The small NSLU2 computer has a USB connector and with a DS9490R1-Wire to USB adapter it`s easy to collect data from a 1-Wire unit onto a hard disk. Then I just need a pH-to-1-Wire adapter, which is what I want to build and describe in the upcoming blog posts. A 1-Wire bus has a much longer reach than a USB bus and that is very convenient for many purposes. The pH probe that is supposed to be connected to the voltage amplifier only sends out 0. 059 V per pH unit and using a coax cable will keep out noise. Coax cable naturally terminates in a BNC connector. The voltage signal coming from the pH probe is both positive (pH < 7) and negative (pH > 7). Since the power supply for the circuit is from an ordinary 12 VDC mains adapter and the signal is going to an A/D converter, the ground reference for the voltage amplifier is raised to ensure positive voltages only for the converter, assuming that a normal one is only able to handle positive voltages. I can`t help checking the uptime when I log in. I`m still amazed by how little maintenance this small NSLU2 computer requires. This is usually the case with Linux servers, but on top of that is has low power consumption and small form factor I almost forget that it`s there. Generation of graphs happens automatically so before making...
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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