Last night I started working on a servo tester using the 555 timer. As I am doing more with servos as of late I felt a stand alone servo tester would serve me well in the future. Schematics and board art will be uploaded later in the week when I can finish it and tweak a few things. Today after work I decided I should add a transistor to the schematic for larger servos and loads.
You see them all the time from fresh faced EE students looking to power their new arduinos and LED’s. The simple computer power supply hacked and forged into a fixed output power supply for a range of very common voltages. Which is exactly why I did the same thing. I like my design, rather than trying to cram it all into the PSU case I attached a piece of bent Lexan to the underside of the case and brought all the wires out.
Yesterday I went to my local Hamfest and picked up a few Z80 Processors and other goodies. While reading the datasheet I noticed something. If the data lines for the z80 are held in an active low state I will send the CPU a series of NOP (No-Operation) commands. A quick glance on the internet confirmed this and I quickly breadboarded a prototype. I used a manual pulsar as the clock source, tied data lines down and sent the four least significant bits of the address lines out to some LED’s.