Task: To study the possibility of using of the DIY touch capacitive sensor on the pcb
Tools: PIC18f1230, a pcb with exposed square copper areas
So long story short, my cheap amazon lamp did not survive for a long time, but I really did like the LED light it gave. In the article below I will describe how to use a copper pad and the pic microcontroller without much additional circuitry.
Recently, I was constantly struggling with the fact that microchip was removing more and more support libraries, so it was not wise to rely on them in all projects. Anytime I return again to my old functions – if it used the support libs, there is a pretty good chance it is screwed.
So this code works with XC8 version 2.36 and doesn’t require the involvement of extra support lib.
When I started to dig into USB topic it was quite a surprise, the amount of efforts the smart people around the world put into it just unbelievable. Even more fascinating fact – it actually worked out. The excitement reached some saturation when I realized the prices (: Vendor ID will cost you 5 grands per year, want to use a USB logo – no problem, just add another 6 grands on the top. Now we could test the compliance of your device with our standard for n grands… The companies using USB are listed on the website www.usb.org (USB Implementers Forum – USB-IF). The curious one could just count a number of companies and calculate the profit just from the year subscription, and this thing is going on for a long long time already. Well they have definitely built an addictive stuff. I, personally, have found the usage for my projects a bit excessive, I definitely not ready to put 5 grands per year for USB in the cheap humidity sensor.
Now, there are tons of different information, it is really challenging to grasp all at once, I will be honest and won’t pretend that I got everything, have a lot of holes in the knowledge, I just need to make it alive and respond to my commands. So, what I gonna to do is to show the info which looked important to me and then will conduct two experiments on this “foundation”.
I was working on a small project where I needed to catch a certain button pressed event. Sounds simple initially, but I have 10 such buttons and it means that I need to have 10 IOs, or port expander, or make a digital matrix button handler (like 3×4 keypad) but these all variants are boring, I wanted something more interesting and make something like a DAC based on these buttons which will be digitazed by the built-in ADC in pic18f14k50. Thus, we will use a single port instead of 10, by cost of the more complicated code.
Let me start as usual – from reading of the datasheet.
A situation in place was the next – my half done amplifier was working already 3 years just proving the statement “there last longing device is a temporary one”. It was kind of fine – but it consumes an energy. In a fact a solid chunk of the energy – it is class A amplifier. At some point in time I started to think – why to not switch on/off the amplifier in dependence on the signal presence.
I have added a small additional pcb for my diy amp project, which is dedicated to detect the drop of VDD voltage level and saving the data to EEPROM at reaching of the certain threshold. All how I described here, I used the built-in comparator from PIC168f877a.
It is a pity that I have not added this feature to the main pcb, so now all solutions looks unaesthetic.