Looks right to me. As for a source of TTL chips, you may wish to visit Futurlec since they have a large amount of components, especially logic chips and sockets, for cheap. What I mean by cheap is that you could buy 100 14-pin DIPS for 6 USD. Jameco, by all means, is still a very good source for components -- just shop around. The only caveat is that they seem to, when you use a credit card, charge it in Australia so you have to clear it with your credit card company first. Just as a side note: For your signal generator, it could be minimized even further by applying a little Boolean manipulation to it. Since learning is of great importance in life, I will leave you with this question: Is this equation correct? Sig Out = !a!b!c!d = !(a + b+ c + d) Number of gates for !a!b!c!d 4 Inverters, 3 2-input AND gates Number of gates for !(a + b + c +d) 1 inverter, 3 2-input OR gates
Nope, according to my math. Yes, according to my software. But there is room for error if I use OR gates (the 1 ms between switches). I think Its just best If I stick with AND gates, besideds, it doesnt really matter when you can buy a 7404 which has 6 NOT gates on it. -- Its acctualy not the TTL (I just said that because it was the first thing that came to mind ),but .5 cents for a 74ls90 is better than .8 cents . Although, I was wondering If I should buy some sockets. I think I might as well its only 1.33 for 20 of them. Well, depending, which should I get. The nice cheap solder tail or the machine tooled. LED's are the most expensive at the moment. ~140 for ~10 bucks. But its not that bad of a deal, ~.08 cents for a 500 mcd green led. I also need to find some good cheap wire for soldering all this together, a 10-20 foot roll should be good. Any suggestions? thanks.
Might as well actually contribute to the thread. Straight hard logic implementation of a digital clock utilizing JK Flip-flops wired in synchronized fashion. Top: Bottom: Special Features: Pulse-width-modulated intensity based on ambient light. Settable alarm with recording chip for custom alarm sound Hard Blackout/Brownout catching that will alert you, if nearby, via alarm
Spectacular job. I would imagine it's not too easy to reprogram though. What recording chip are you using? I was thinking of doing something similar. Stuart
I will be utilizing an IC titled ISD2590 since it can be controlled without a microcontroller. The alarm will be carried by comparing current time with a set of registers that can be set by the user with the clock alone. The comparing is done with only 2 XOR gates by utilizing 8x1 MUXs and a counter. I love stuff made from simple ICs as well; that is why I chose the hard-wired route instead of the software way. I do, however, have FPGAs that can implement nearly all of the functions my clock can perform in a little package but that would take out all of the fun.
I have got some not so good news. Ive searched around and found the ABSOLUTE best prices for these parts and its about 50 bucks. Putting it blunt, I dont have 50 bucks. But have no fear, I have an idea! Ill make a binary clock! Some notes: Yes, I am missing 1 NOT gate and 2 resistors, but that limitations because of the software. In the final design they will be put in (with correct values). This is a little less than HALF what the 6 digit would be. 20 dollers to be exact. Which I am very happy with. Also the leds will be facing other way around, 1 will be on bottom not the top.
Here's my binary clock. Admittedly, i took the easy option, using a microcontroller as opposed to hard logic. It's a pretty basic design, and nothing too elegant, but it does work, and impresses geeky friends and is cool.
Very cool clocks. I was just about to click the "finish order" button when I thought of something from a page back. The 74ls90 ,once again, can only source 2mA. Unfortunately, any other 74xx cant source 20mA or it isnt in production any more if it could sink or source that much. The transistor idea comes back to mind, (I think it was 2n2222a's right? It is only 50 cents for a bag of 10) unless, do you have another idea? I dont really want to do the BCD to binary conversion with more ICs either. Thanks.
2n2222 would work assuming the 74xx90 goes high for active on the output. You could, if you want, try inverting the outputs with inverters and attaching the LEDs' cathodes to the outputs of the inverters. This way, the inverters would be sinking the current.
Yes, the 74ls90 does have high output. (At least all the datasheets Im looking at say it is ) I had also thought of that, not gates are the same price as a couple of transistors. I might go that route just to stick with TTL. Thanks.
Hi Chris, glad to hear things are going well now for you. Seems tho I took a down spin on life. My health has been failing and been taking all my extra electronic funds to make copays and such that I havent been able to do anything. But i am starting to get better but need couple of surgeries soon so looks like i have to put my projects on hold for now. Sry guys.
Been busy again - here's another 1" clock with improved driver board. Apologies for the poor quality photos. Had to take them on a crappy phone camera.
Sorry, the picture is poor - the displays are actually green Haven't found any places to get 1" or bigger white displays other than LCLED, and I don't really want to have to have them shipped from anywhere but the UK. Next in line is a 2x16 LCD using custom characters to make digits that are two lines high because I have about 20 displays laying around at home doing nothing.
Sorry, my fault... On the picture they really look like white displays. Why? Joseph from LC-Led is a fine man. Once (on all the orders that I made) I had a package that I never did receive. Joseph refunded me completely. Finally the lost package was returned to LC-Led with the mention "not claimed" (I never received a message from the postoffice that a shipment was waiting on me!). I now found 4.0" white displays at LEDs-buy but they are expensive compared to the LC-Led prices. As my company has to make some spendings I think I will buy them with the company's money. Pictures, we want pictures! CD
Great job steveyG. I like the fact that you used SMT chips. I would love to buy a kit from you if you might do that. Your in the uk correct? I'm in the us. Might be a bit rough to work over here.
SteveyG, your work is immaculate and professional. I have finished the 1st board of my clock, now for the 2nd board which will have even more wires.
Xiachunyi, What size wire are you using and where did you get it? I've been looking for some really fine (~34 to 36 AWG) solid PVC or similar insulated wire (not enameled though). Thanks, Stuart
The wire I use is 30 AWG and from Mouser under the manufacturer name of "OK Industries". I usually just order the 100' spools since I use a large amount of wire.
