Raspberry Pi-3 Laptop

Description

I wanted a Raspberry Pi Laptop to take into coffee shops but for some reason they are very expensive. The green “Pi-Top” on Ebay looks nice but is about 850 dollars complete so I wanted to build one that was cheaper.

My first attempt was basically a failure…a 7 inch screen…too small for a Raspberry Pi computer to see the screen properly and I posted that project on Makermaze in the Arduino section.

After seeing the pi-top on Ebay, I knew I needed a 13 inch screen but unfortunately they were all over 150 dollars. Then I found a Seiki TV in a local Thrift Shop for 5 dollars–took it apart and realized it uses the same screen that is sold on-line for about 150 dollars. The driver circuit board in the Seiki is nice and small, has a long cable to the screen, has thin speakers, and had a narrow bezel which mounts easily to any flat surface. Resolution locks in automatically at 1370/768 which is quite clear. (Any similar TV would also probably work just fine…all you need is an HDMI slot and a 12 volt tv).

Next I needed a housing, looking around I found an old laptop cooling base for about 20 dollars. I discarded the fan, slit the back open and installed some hinges as you can see in the pics. The tv screen and frame was thin, level, and fit perfectly onto the laptop lid.

For the batteries, I’m using a pair of 6 volt 1.4 AH lead acid batteries in series…they sit at around 13.5 volts. Since the Raspberry Pi needs 5.0 volts I’m using a DC to DC converter to reduce the 13.5 volts to 5.0 and running that to the Pi3 (as shown in photo.) The Seiki display board conveniently happens to take 12 volts so I just connected it directly to the batteries which are 13.5 volts when charged…close enough as the voltage drops to about 12.5 volts when under load. The display draws 1.2 amps, and the Raspberry Pi3 draws about .2 amps as you can see in the pictures. It’s nice that the DC to DC converter shows you voltage and current draw of the Raspberry Pi.

The circuit board was running a bit hot so I mounted a mini fan with a toggle switch as you can see in the photo…now it stays cool. Near the top you can see a small display showing 11.9 volts which is the full battery voltage. Battery time is about 40 minutes with the lead acid batteries and it keeps working down to about 10.2 volts so I’m looking around for a bigger 12 volt 9.8 AH Lithium pack.

I used a wired keyboard and mouse for efficiency as I didn’t want to mess with keeping wireless units charged up. The plexiglass layer was needed to protect the main parts and is also needed to hold the keyboard if you want to use the keyboard as in a laptop.

Everything folds up nicely and there is enough room to hold the keyboard and mouse internally as shown in the last picture. I can post the Ebay part numbers if anyone wants them. The batteries are charged thru the connector located in the front corner.