Computing is fun, once again

image of zx80

My first “system”

This was my first personal computer, Sinclair ZX-80 from U.K . (BTW, It’s not ZEE-X. It should be pronounced, Zedd-X) for $199. You still needed a TV monitor. So I had to shell out another $70 for portable tube based TV. Membrane keyboard was so primitive it took me 30 minutes to enter a simple basic program. It came with 1k byte of S-RAM and Z80 CPU operated on 1Mhz speed. The screen memory was shared with program memory, so if you enter long program, it starts reducing the displayable screen lines. It did not have dedicated display driver so every time key is pressed, the screen would blink. Still I had a lot of fun from this “system” back in…. 1981.
Fast forward to today. The core of the system is Raspberry Pi , so called $35 computer from UK. It actually cost me $42(plus shipping) from There is also BeagleBone Black (aka “American” Pi) for $45 that can be used in approximately the same way. The Raspi runs on 700Mhz Arm processor and comes with 512MB of RAM. (BBB runs on a bit more powerful Arm processor@1GHz with 512MB or RAM) You use2GB or larger SDHC card to copy bootable linux image downloaded from the internet and pop into the SD card slot. (BBB has 2GB internal memory that is already prepped) The system will boot up Linux OS.
It connects to USB keyboard and HDMI monitor. Since it has Ehternet connection, one can also use it headless. I ran mine headless and use terminal program from my PC to control it.
It has some of I/O pins exposed so you can connect it to electronic components such as LED or motor, or get input from temp sensor or switch or whatever. If you goof up and destroy it, it will cost you mere $42 to replace it, so, have no fear.
As said, to make a complete computer out of it, you will need a keyboard and monitor.
USB keyboard is cheap, but HDMI monitor is not. Enter “lapdock” from Motorola. This was sold as a docking station for Motorola smart phones but apparently was a big flop although Lapdock itself appears to be a beautiful device. It looks like a Macbook Air.
One time you could buy this thing for $40 from Amazon. Original price was more than $500. Then somebody “discovered” that the lapdock can be used with the Pi. Now the instruction of how to connect the Pi (or BBB, or whatever the dev board you want to connect) to the Lapdock is everywhere on the Internet. As of today, the cost of “Atrix 4G Motorola Lapdock” is about $120. I got mine for about $80 just a few weeks ago. Economy of scale must be working nicely. Spend another $20 for cables and you really have a real computer for less than $200.
Computing is fun, once again.

$35(Raspi)+$80(Lapdock)+$20(cable Set)+$8(SD Card) + S&H($12)=$155 system

$35(Raspi)+$80(Lapdock)+$20(cable Set)+$8(SD Card) + S&H($12)=$155 system

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