Long Time Delays

I have purchased a Velleman-kit (K6200) which offers "0 to 60 hour start/stop timer". It is really excellent for the requirement of long time delays. I will do significant modifications to use it as a intervalometer for my Panasonic FZ20 camera. One easy modification is to convert the output to a monostable, relatively short, pulse. If you require my current schematic I will send it. What I need is a method of calibrating long delays - like 1 hour to 24 hours. I have in mind to do something like a lap stopwatch, but triggered from an external source. I can write good VBA programs, but need assistance with a method of triggering the timer function. Can someone tell me how to trap a simple level change event from any of the following: Standard USB port, Ethernet port, Microphone input port. My laptop does NOT have serial RS232 or parallel printer ports.

 

It would be better to dump that kit, and use a mirci-controller approach. But for this project do not use PICAXE. This will be a very accurate solution and since you have done some programming before it should be easy to adapt to micro-controllers

 

Why not a PICAXE? Gut a battery powered desk /wall clock to get a tiny oscillator that outputs a very accurate 1-pulse-per-second or 1-pulse-per-2 seconds signal. Drive a PICAXE interrupt input. Program a count for whatever you want.

Ken

 

Thanks Bill for the advice and starting a new thread; also to t06afre and Ken for comments. I stopped writing binary, assembler, fortran etc many years ago in favour of VB and VBA and don't relish the thought of going back. (Just lazy in old age I guess).

Bill: your offered 4060 circuit is interesting as a concept. The 4536 as used in the Velleman kit does that all in one chip. I have modified the circuit a lot, added a 556 and 2 transistors, a simple RTL gate and a triac switch. This gives me the required timing plus a means of turning on a lamp for a few seconds before releasing the shutter. The fine adjustment for timing is analogue, and that's why I need to calibrate the whole thing - so need an accurate "counter/timer" as mentioned earlier.

I will probably have to purchase a RS232 to USB converter cable but don't really want to spend unnecessarily. If I could detect "something" at the USB port without additional circuitry I would be happy!

Any ideas?

 

Thanks MrChips, but like I mentioned: I'm kind of past low level programming. Probaly forgotten most of what I learned way back then. Mostly quick, fairly accurate, cost effective (cheap - maybe?) results are what I'm after now.

I just need to detect some kind of event at the USB (or ethernet) port whithout spending any more. Then I will do a counter type VB (VBA) application to calibrate my intervalometer, which is already half constructed and field tested.

 

I think this belongs here - because it is an associated idea I have which someone may be able to help me with. If it belongs somewhere else then please move it and let me know.

I want to measure the time (period) of long delay events generated by timers and related circuits. The times are from a few seconds to many hours. I have used "Audacity" to view the (square wave) input to the sound card. Because of AC coupling (and indeed the lower frequency limitation of the sound card), the resulting waveform is displayed as a differentiated pulse at each level transistion. With appropriate external filtering I can accurately determine the direction of level change and the exact time of the change. Using Audacity's zooming and editing features I can measure the time between transitions. When the periods are a number of minutes to maybe an hour or more (not yet tried), I can visually do the measurement. However you may understand that to measure (say) several hours may be difficult (if not impossible).

Now, my idea is to "trap" the transition event(s) in VB or VBA and then write a trivial timer/counter application to display results. Please, can someone tell me how to "trap" those events from the sound card? I will write the rest of the application and share it, free of charge, with anyone who may be interested.

 

Why are you stubborn about not using a micro-controller. Not offended in ay way but quite puzzled. The days then you had to use assembler is long gone. And for the price. A full starter development kit do not cost much. As MrChips suggested a MSP430 is $10. You may also look at the Arduino platform. The way you want to things are quite awkward and clumsy.
Just curious

 

I'm with t06afre. If you have any programing experience, the PICAXE with BASIC should be a piece of cake for you.
All you need is one of these: http://www.picaxe.com/Hardware/PICAXE-Chips/PICAXE-08M2-microcontroller/
Probably one of these, if you don't have a serial port (who does these days): http://www.picaxe.com/Hardware/Cables/PICAXE-USB-Download-Cable/
Two or three resistors, depending on your pulse source and a 5VDC surplus wall wart, and the attached circuit made from a battery desk clock. You have all you need to test, count, and report to VB the time between input pulses down to +/- 1 second intervals.

Ken

 

Sorry, SinewaveMan. A lot of us have been through the technological transitions that MrChips refered to. Once you step over a threshold, it's hard to see why anyone would want to stick to the old, more complicated hardware.

So I still stand by my suggestion.

(Mine was a single vacuum tube, VHF super-regen receiver. )

Ken

 

Hi all. Thanks for your interest in my quest.

Not stubborn - just exercising a long-ago learned culture of "fix or salvage" as opposed to "throw away and buy a new one". Except for the 4536, everything else is from my scrap box(es), including hardware: faceplates, knobs etc. I must admit the 68xxx is a bit difficult to get off the PC board, so I bypassed that one - btw the token ring controller I designed, built and programmed with a full set of on-board ISO layers 1 to 5 still works; the 2 Mbyte RAM required an extra daughter board!.

My early experiences are still fascinating to me in view of the steps I have followed to the present. I can confidently say "been there, done that, got too many T-shirts!".

My first was a single valve HF regen (around 35 Mhz). Later modified to a single channel (bang-bang) RC boat control receiver. Won a few international races with it.

Other exploits: too many to bore you with (remember the Mullard 5-10 and packet radio?) - but suffice to say that I taught so many students at college the arts of GOOD microprocessor/computer design that I now relax with my scraps and salvaging. Semi retirement does that to you!

Now here's the challenge: "Anyone know how to trap . . . . . . . . . "?

 

At the risk of further "necromancy", here is my (possibly) final comment on this thread: I have successfully managed to measure long time delays for my intervalometer using an audio analyser application on my PC. If anyone is interested I can write a brief tutorial showing how. If two or more positive replies are received then I will do it.

 

I'd like to see how you did it.

I'd like to see how you did it.

 

Hahahaha! Well done - OK, I will prepare a little tut for it.

 

If the poster was going to attempt to market an idea ... yes, by all means recommend the most current topologies and components. If they are doing it for their own gratification, let them work with whatever they want.

I repaired equipments designed in the 40s, 50s, 60s, 70s, 80s, and 90s. Beam Switching Tubes were in the divider circuits, phanastron oscillators were used in another suite of equipments, chopper relays distributed error signals, and the ever present vacuum tube multivibrators. Servos were quite common. If someone wanted to build a divide by 10 circuit using a beam switching tube ... good for them. Maybe they want the personal challenge associated with such a design.

It certainly would be for an eccentric client if they wanted a phanastron oscillator circuit.

The 741 still rears it's head ... why? ... because that is the most studied OP Amp out there. It's the easiest one to see op amp parameters. I believe that is why it's the premier chose of most of the students out there ... they are familiar with it. It would behoove the instructors out there to cite their specifications in a way that the student must choose something other than the 741.

 

I don't know if this is the correct way to submit a tutorial. If not, please adjust and let me know.

I really want to write a delay timer application. Please tell me how to trap those pulses as events in a VB program.

Any questions: I'll be happy to answer as best I can.

Best wishes to all for the festivities and celebrations at this time.

 

It's probably best submitted as a forum thread? Some people don't like to open PDFs and in it's owm thread other people can contribute opinions and suggestions etc. It can also be searched for on the forum search or google search which are great at finding thread names.