DIY Speaker for Dance Events

A small presentation of a DIY speaker I have built myself. I've built it to take out when I'm going to teach dance or if I'm doing a little dance show or maybe a party in a place where there's no sound system. The speaker is energy efficient and can make great sound powered on just a 12 volt battery. There are two videos the first one focus on of the speaker. The other one focus on the amplifier. The amplifiers of a particular type of Class D amplifier called T-amp or Class T amplifier or the Tripath chipset Class T stereo amplifier. 

Inspiration I had for this project

https://www.instructables.com/id/Battery-Powered-Mobile-Party-Sound-Systems/

The TNT BFB a.k.a... The Big Fun Box
http://www.tnt-audio.com/clinica/bfb_e.html

3.5 inch HDMI touch display review / recommendation

I have tried severely small screen for my Raspberry Pi project "Noteypi". This one is really the best. 

It is named KeDei and it can be found on AliExpress for varies prices. The cheapest I have found is 22 $ with free shipping. It is not advertised under it's brand name it is offered under the name. 

"3.5 inch HDMI LCD TFT Touchscreen Display  for Raspberry pi 2 and Pi 3 Model B"

or 

"raspberry pi 3.5 inch hdmi LCD touchscreen touch screen 60 fps high speed 3.5inch better than 5 inch and 7 inch"

It can be recognized on the pictures by the connection to the Pi witch is split in two as you can see on the picture here below. Most other products have the connection as one block covering all the GPIO of the Raspberry Pi

As I said it is the best of the many 3.5" and 5" screens around in my humble opinion. Especially when it comes to touch precision. 

It is a resistive touch screen as oppose to the capacitive touch screens. Most of us have gotten used to capacitive touch on our smart phones and tablets. A capacitive touch screen uses the static electricity of the body to locate the position of the finger on the screen. A resistive touch screen uses a pressure point. This method gives much higher precision so it is more suited for precise on screen drawing witch I find interesting. Most other 3.5" and 5" screens I have tried have some problem when it comes to drawing on screen. The line wobbles caused by some electronic inconsistency. This one rarely wobbles and is over all fast and reliable to work with. It is excellent as a hand drawing device. I made my install based on Noobs. I followed some manuals and got the touch screen to work but I never got the screen calibration to work with this set up. That means that I have calibrated my touch screen manually by adjusting x-width x-height y-width y-height in a setup file. Hard work but I did learn something from it. I use the screen at a resolution of 720 x 480. That is a good compromise. If resolution is to low it is almost impossible to use the screen because the programs interfaces take up to much space on the small screen. I can highly recommend this product. As for on screen keyboard may I recommend "onboard". It works very well with the setup an support local languages.