Want to build a computer? No, I don't mean buying a motherboard with a Pentium and some RAM and putting it in a box, I mean solder or breadboard chips and wires and press buttons to code in machine language. Build the Cosmac ELF, a popular hobbiest platform whose instructions were published in the August 1976 issue of Popular Electronics. A few photos of the ELF show differences between the original and later models. The Machine Room tells the history of this "'freeware' computer". Supposedly the 1802 processors are still manufactured for industrial applications. The advanced model could output a video signal (!). If anyone can find more instructions on building other models, or if you have an ELF story, please post a comment below!