I had a lot of IC's arriving by mail over the last month to prepare to build this robot. I made a few small kits and the rest kind of spread around my work area like chaff in the wind. Having a larger project box earlier on would have been a good idea. So, after getting everything organized, I will start with a breadboard with these components:
- MC14500B Industrial Control Unit (ICU)
- MC14512B 8-Channel Data Selector
- MC14599B 8-Bit Addressable Latch (This one is quite clearly a knock-off)
- MC14040B 12-Bit Binary Counter
- AT28C16 EEPROM
Normally, I would just start soldering stuff as it takes a lot longer to put it in a breadboard and then lay it out again for the proto PCB. This project is complicated enough and has a suspect knock-off component, so I will take the time to put everything in a breadboard first. Ideally I would like to use a DM72LS471 PROM for the memory as it is a small dip package, but I don't have a way to program it yet. Instead, the AT28C16 EEPROM will be very easy to program and test with.
On a related subject, my experiment yesterday that resulted in a spinning robot made me realize I needed an on/off switch. Every time I worked on the robot, I wondered what the rectangular cut-out was on the front. Then yesterday, out of the blue, while doing something completely different, it dawned on me that it was for a switch! And not just any switch, one of the most common switches ever. It is a 250V 3A DPST switch that shows up on tons of old tube amp equipment from the 1950s and 60s. In fact, there are 7 of them on the stereo system I am listening to right now. Since they are so common, I had a few tucked away. It didn't dawn on me earlier because it is a huge switch compared to the robot. The fitment (like the TO-3) is a bit off too. The screw holes are so small that I really don't have any nut/screw combos that can fit. Drilling the screw holes out much more is not really possible since they are so close to the switch cut-out. Also the holes in the switch are much bigger. I'll figure something out. I have gotten really good at stripping this thing down and reassembling it...
Note the switch taped into position. That is probably all I will do today... It is a nice day out!
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