Binary LED Calculator

After comparing the new solder joints to the ones I was making with the old iron, I decided to start completely over with the LED Binary Calculator. This time I used DIP sockets and new protoboard I was able to buy when I bought the new soldering stuff. This protoboard is 25 holes wide which is really convenient since each of the eight LEDs needs three holes width. There were also just enough of the old red LEDs I was using before to start over with. The solder didn't take to them very well at the beginning so I had to scrape off a lot of the coating that had formed on it. Because I didn't have a battery holder, I soldered on an 8 pin DIP socket to use as a power connector. I taped wires to a CR2032 battery and I stick the ends into the socket for power.

After soldering everything together I ran a test of the LEDs. They only worked correctly once and the only way to get them to work again was to remove both the shift register controlling the LEDs and the MSP430. Toggling the master reset of the shift register didn't help either. Upon closer inspection it turned out the ground connection to the MSP430 had come loose. I was surprised that it ran at all with no ground connection but I have seen it do something similar on a breadboard too. The buttons worked fine from the beginning except that two of them were linked by a solder bridge. After I fixed that, the whole calculator worked as expected.

First Project

After flashing a few LEDs and reading a few buttons with my new MSP430 I decided to start work on a simple calculator. For output I am using eight LEDs to show the numbers in binary. To do this I am using a 595 shift register. Since I am using an MSP430G2533 I would have enough pins to light the LEDs without it but I wanted to practice using shift registers and be sure I would have enough current. For input I am using a 165 shift register. This will give me room for eight buttons. I have always been a fan of Hewlett-Packard's line of RPN calculators so I decided to use this notation for my calculator too. The eight functions I decided on are 1, 0, dupe, swap, push, pop, +, and -. Programming these simple functions was not difficult. After I saw that everything worked fine on a breadboard running from a coin cell battery, I started soldering it onto a piece of protoboard. This will be good practice since I have never soldered anything before. So far only the LEDs have been soldered but I hope to finish the rest soon. Here you can see the protoboard and the breadboard with the parts of the circuit that haven't been canabalized yet.