July has been characterized by many technical problems. While I was writing the first “boxed project”, I needed to change host twice. I hope to have finished with mishaps in order to publish very soon one of my favourite projects. Probably, it will be called: Three-ways automatic watering system. Thank you for your patience
Go to the project BP003 if you want to add a bi-colour LED backlight and a power supply board on the thermometer. In addition, an useful video clip is available there to watch the thermometer in action.
I wanted to build this project because I needed a thermometer in my house, but also, because I wanted to have the occasion to use a LCD display for the first time.
I have always been fascinated by LCDs. Their capability to make numbers, letters and drawings on a glass plate is something magic. Thanks to this project I learnt a bit more about them and I discovered the tricks of the wizardry. Despite this, and even if the LCD displays have become obsolete, I still think they are the result of an amazing technology.
I chose to use the ICL7106 as the driver for the LCD display. This specific IC by Intersil, has also inside an A/D converter necessary to “transform” the analogue signal generated by the temperature transducer into a digital one. For practical reasons, I decided to split the project in two different sections, and then, in two different boards: one for the LCD display and another one for the ICL7106 IC.
To ensure a proper function of a system, keeping the temperature of all devices within their working values is very important. Since a common working range of temperature is about from -20°C to +85°C, the lower limit is generally negligible. On the contrary, the higher level could be a problem since all the devices, some more and some less, tend to increase their inner temperature. In certain situations, especially in power circuits, it is necessary to use some cooling devices in order to cool down the hot ones and make the environment well ventilated.
Initially I built this PCB because I was fed up to hear the annoying low frequency noise from the speakers of an old amplifier. The issue came from the power supply that clearly wasn’t very good. The residual 50Hz signal from the AC line, technically called ripple, was so high that it generated an awful fixed background sound. By installing this PCB, after the existing PSU, I solved my issue.
Later, I decided to use the PCB as a general power supply to test my projects. It has always worked perfectly even if setting the voltage output by trimmers was not very comfortable. For that reason, if you are thinking of building it for that purpose, I suggest to substitute the trimmers with potentiometers by connecting them with wires to the board or, better, redraw the whole PCB mask.
By using the LM3886 it is possible to build a very small PCB but with the performance of the more complex and expensive commercial power audio amplifiers. Of course I’m not comparing this amplifier with some super ones available in the market, but you’ll remain amazingly surprised listening to how good it sounds.
The basic configuration suggested by the LM3886‘s data sheet works well already but it is possible to change something to make it sound better. For instance adding a few extra components to filter the signals more carefully, or, since a handful of components are necessary, it might be worth spending a little more money to buy some high quality ones.
As I’ve already promised, on 1 May I’ll start publishing the first electronic project on andy-progetti website. It will be an amplifier, a very simple single PCB, but you’ll remain amazingly surprised listening to how good it sounds.
In the post you’ll find all the necessary material to build it: of course the schematic and the pcb mask, but also the files in Eagle format.
Start to power on your soldering iron
Why this site
Since I was a boy I have been interested in electronics. Until today, I fixed and burnt lots of stuff, built hundreds of PCBs, some were bad because they didn’t work or were useless, some others made me proud of myself. I’d like to share this with people.
Why the name
Andy, as might be expected, is my name – progetti means projects in Italian: Italian is my nationality.
What is it
It is a collection of my best PCBs with the complete instructions and everything you need to build them. Some come from original schematics, some not, often a mix of both. Publications are split in three different categories as explained below.
These projects are the single elements that, combined, form a system. For that reason they generally cannot be used by themselves, probably you should connect them to something else, some other elements, some other projects, some other PCBs.
Here we have the systems described before. Combining some PCBs in the right way, it is possible to build complete devices. In most cases, however, it is not so easy because some elements of the system might not be compatible or ready to be used with the others. In these situations sometimes it could be enough to change something in the elements, but sometimes it could be necessary to add one or more specific PCBs in order to interface properly with the single elements of the system.
Guidelines, tricks, manuals, curiosities, etc, belong to this section. Here you should find all you need to make the projects published in the site and something more.
If you want to e-mail me please use this address firstname.lastname@example.org