June 29, 2008
For those interested, I have added the links on the right to the following electronics Manufacturing companies.
Maxim / Dallas
On Semi (Motorola)
Microchip - Mostly known for their PIC micro controllers.
I will be adding a couple of more at a later time, but not many.
To follow are:
and a few others.
June 28, 2008
Finally, I was able to have some time to continue slowly on my clock project. Up until recently, it was actually a counter from 00-99, incrementing every second or in its original form, manually. I was finally able to add the 74ls08 to it, so it would reset after the second '192 reaches 6, the B&C output that represent the binary 6 are on the input of the AND gate, of which resets the second counter. For those that don't know, six in binary is "0110". You can see the "truth" table in my previous post.
These images are pre-74ls08
Yes, at the moment, I am using a battery pack. The 78M05 does not have any additional circuitry, like capacitors etc. Its output goes to a special chip (TPS7350 - up to 500mA continuous 8 pin DIP made by T.I.) that regulates to exactly 5v.
On the small board is the timing circuitry. On the larger one, is the power and logic. The single digit by itslef is an INL0394 by Innocor that is pin compatible to a TIL311. The other two are HP 5082-7300. The Innocor is still available and the HP has been updated and is still available too. Both these parts are fairly expensive, since they also include an I.C. that has the same functionality as a BCD to 7-Segment driver. I will try to use a different camera and settings next time, since the images do NOT do justice to the displays. They are much better looking than normal 7 Segment displays.
The oscillator may change later for a device from Dallas-Maxim that gives 32768Hz, and much more stable, or it is suppose to be. Here is a link for it. The part number is: DS32kHz I will try it, if and when I receive a sample from them, since I can not find it here easily in Australia.
The circuit works something like this.
On the big board.
Power->Bring down to under 10v. ->Power 5v. ->(Original circuit up down manual counter)->MC14490 debouncer for switches. 3 switches. Black reset, White increment, yellow decrease.
Power in-> CD4060 (could be any type of the 4060)->crystal 32768Hz (or 32.768KHz)-> with support circuitry->from CD4060 2Hz out -> CD4013->1Hz out-> to large board to the UP input of the 1st 74LS192.
The 74LS192's are connected in such a way, that if needed, they can also count backwards (down).
In the later stages, the circuit will start being built on proto-boards and small ones of those. I will update with pictures again, once that stage is reached. At the moment, I will add the minute and then I will move the project over to new breadboards with a neater layout. Once that is completed, I will post pictures again.
For the moment, I will be taking it easy, due to my lower back problem. It has gotten worse, and now I have been diagnosed with "L4/5 central spinal canal stenosis". So i must be relaxing.
Until my next update.
June 22, 2008
It has been a long time since I updated my blog. Well, let me just tell you, that it has been a very peaceful period, nothing exciting. Now for those very few that know me personally, and for many years, would know that I like tinkering with electronics.
For those that are not familiar with my habits, I should let you know that I go in circles. I might like something, start doing what I like, get bored quickly, and then after some time, I will cycle back to it. Well, it has been a few years now that I had left my hobby electronics. At the time, I was looking in to making a digital volume control, that would include an indication of where the volume was at. Needless to say that it was left in the early stages. I had progressed as far as a reset button, up / down control, single digit display with a TIL311/ INL0397 from Innocor, I actually used the later, and an ON-Semi MC14490 switch de-bouncer. You may say, why did you use that, simple, ease of use, less components.
Below, you will find a guide I wrote for myself, like a journal, so I will know what I am going to be doing. The part about the clock, was entered on
Take care, everyone and have fun.
This project will have the following parts divided:
This will be provide by a back for revision 1, by a 100v DIP package bridge rectifier, model 1B4B42 DIL 1A, or a W04 1.2Amp.
Since these are a 1A & 1.2Amp models, they are adequate for all 6 digits, 7 segment displays. Some W04’s are rated up to 2Amps. Please make sure about what you use . A 78M05 voltage regulator would be adequate, just, for the Version one. To be sure though, I would advise a proper 7805 that is 1 Amp. Some “brand’s “ claim that they are up to 1.5A. I can not comment on that, and I will not really want to just try it out for the sake of it. Rule is, if it works, does not get hot, you have proper ‘cooling’ as in USING a heat sink, why experiment? The “L” version in a TO92 package is NOT adequate, since it is only 100mA!!! There are some similar ones that are 250mA. Those are still not adequate… Just use a larger one and get over it. Of course, you can use an LCD module, that works on multiplexing, but I am not looking at it at this moment, but it will drop your power requirements considerably. Unless you have a few of those and want to use one per 7 segment LED! Go ahead, make your life difficult. ;-)
0 0 0 0
The table on the right shows the 4-bit numbers and their decimal values.
The labels A,B,C,D are widely used in electronics to represent the four bits:
- A = 1, the 'least significant bit' (LSB)
- B = 2
- C = 4
- D = 8, the 'most significant bit' (MSB)
Binary Coded Decimal, BCD
Binary Coded Decimal, BCD, is a special version of 4-bit binary where the count resets to zero (0000) after the ninth count (1001). It is used by decade counters and is easily converted to display the decimal digits 0-9 on a 7-segment display.
Several decade counters using BCD can be linked together to separately count the decimal ones, tens, hundreds, and so on. This is much easier than attempting to convert large binary numbers (such as 10110110) to display their decimal value.
Do not confuse BCD which stands for Binary Coded Decimal with the labels A,B,C,D used to represent the four binary digits; it is an unfortunate coincidence that the letters BCD occur in both!
When the tens of seconds reaches 6 (0110), the output is also connected (the B & C ) go to a 2 input AND gate, the output from that, goes to the reset of the one that just reached 6 so it goes to Zero, and is also connected to the Clock input of the 3rd ls192 and increases the count by 1.
Now, since we are counting in 24hour format, to get that to reset, we will need rom the 5th ‘ls192 the C output (4 = 0100) and from the 6th ls192 the B output (2 = 0010). So, when both are active, it will reset the hourly ls192’s.
Included is a day counter.
When the 24h pulse is given, it increments the day counter. Once it reaches day 8, it resets again. So the pulse from the 24h plus the pulse from the number 8 (1000) will reset the counter.
This will be the most simplest of them all. Just seven LED’s of either 3mm or 5mm, depending on what you want to use, or even rectangular 2mm x 5mm x 7mm ones, what ever takes or makes your fancy. Also, six 7 segment LED’s for the time.
Version one point one, this will use the TIL311 from TI/ INL0397 from Innocor (now JDSU).
Version one point two, Instead of the TIL311 it will use the HP 5082-7300.
Notice: Both 1.1 & 1.2 use an internal integrated BCD decoder and have their own display, that way, one less I.C. is needed, no need for a BCD to 7 segment decoder. The downside is that you can not create your own display scheme, only the normal 0-9 & A-F where applicable. These display’s average around the 10$US price range up to 30$US EACH. You may be lucky and find them cheaper, just like I was with the HP version. They have a different orientation, package wise. The pins are either vertical or horizontal, what I mean is that the pins are either horizontal to the body or vertical. The TIL311/ INL0397 are vertical and on the HP are on the top and bottom, so they are horizontal. This is the version I have started with on the bread boards.
Version one point five, might exist, if instead of using normal 3mm or what ever LED for each day, I was to use an Alphanumeric Segment display, to show the day of the week. This is very possible to be made.
Version two, will have a considerable more higher power demand! 6 digits for the time, 3 digits for the day of the week, 3 digits for the month and 4 digits for the year. So that makes it a total of 16 digits. At an average of around 1.2mA – 2.5mA per segment, that can get to be a fair amount if you want to try out all the segments of all the LED’s at the same time (for test purposes of course…). But in normal use, either of the two should be just adequate. The leap day will need to be done manually.
Version three, if it reaches to there, will have a logic layout change to compensate for leap years. It will have a start year on a leap year, and a counter, of which when it reaches 4, it will trigger the leap date. That way, when the person is fixing the year, it will know from where to count, and adjust February accordingly. That will need a lot of AND gates and other logic. I may never reach there, even if I have the thoughts in my mind at the moment. So it will have a combination of input for the YEAR and month, and if both are together, then when the date is added, it will add one day extra and reset it to go to March.
Version four, will have an alarm function. It may have rotary BCD switches to encode the alarm code, so when the time is reached, it will go off. This may be implemented before version three.
Pulse and clock.
Pulse generator. 1 second increment. This is the heart of the project. It will provide a pulse every second to the decade counter an 74ls192. 74ls193 binary counters can also be used in conjunction with AND gates, so when they reach ten (10), they will reset and provide the pulse to the next counter. Once the second counter reaches 6, with the use of an AND gate, it will reset the seconds counter and send a pulse to the minute counter. Again, the logic is the same.
Now for the hours, there is also an AND gate needed, so once the decade counter reaches 0, it will pulse the second hour digit, so once both read 2 & 4, it will reset them to 00 and then will also send a clock signal to the day counter.
The Day counter.
The Day counter will receive a pulse every time the clock reaches the 24 hour. The pulse that resets the two digits displaying the 24 hour, will also send a pulse to the day counter.
This will be a 4017B decade counter that has direct output for LED’s to be driven. At this stage, there are two options, either to have seven independent LED’s, with the colour of your choice to represent the day of the week, or have an Alphanumeric display to show the name of the display. In revision one, it will only have LED’s for day of the week, and the project will conclude here.
Revision 2 only.
This will advance the circuit even further. It will be getting the pulse from the 24 hour reset. It will not use the 4017 as the heart of it for the months, but a 74ls193 binary counter. The 4017 will be relegated to another choir. It will be used for counting the days (x2) and the year. The ‘193 will be counting the months.
I have already started construction of this project. I have bought some rectangular LED’s plus the HP display’s from eBay. One of the later things I bought, was another pair of bread boards since the two I have would not be enough (ok, I hate to make it very tight… on the bread board, and was starting again an old project I had that was a counter, I did not need to change anything, except the voltage regulator to a stronger one. I already had an MC14490 switch de-bouncer for manual counting. So all I did was add the HP I.C.’s and leave the Innocor in place as a reference. It is getting very tangled now with the seconds display. I will now need to put my 1st AND gate. I have finished doing my 1Hz clock. Using my Multimeter that also has a Hz counter (4 digit resolution), it shows that I am doing well. 32.76KHz (it can not display the whole 32768Hz (or 32.768KHz). As for the seconds pulse, it is NOT 1Hz, but 0.999Hz for some reason. That is good enough for me, since I do not have any fancy electronic devices! Only two Multimeters and components, oh yes, and some screw drivers. Although what I do have, is a lot of love for these things and passion and a lot of hair for pulling out ;-) –NOT! I want my hair, hehe.
Saturday, 21st June, 2008
I must say, I had a hard time getting the crystal to give me the proper frequency. I needed to see a second design, of the same thing to finally clear it up in my head and get the whole thing working! I thought I actually had a faulty crystal, since it was giving me a smaller frequency, but all it was, was my wiring. First time after the second implementation worked right away! No need for a trim cap for me. I will be taking photo’s at a later time, like later today or tomorrow to add to this blog.
Sunday, 22nd June, 2008
Over here, you will find a great article on how to do Nixie clocks. There are actually so many of them now on the web, but this one goes in to great detail for many things. Anyhow, this is where I used the part for the timer. There is nothing wrong with it, just for me to be able to conceive it and implement it in a breadboard was not easy, until I came across this one. For some odd reason, I was able to implement his layout easier, even though they are both the same thing! If you want, just open the pdf of the logic part (schematic).