I'd appreciate recommendations for a simple toggle circuit please. Typically I've used half of a 4013 in clocked mode, preceded by a Schmitt made with half a 4001. But I'm having trouble getting this working with my current project.
I've made a capacitive touch switch. It works fine, giving a (rather noisy and slow) positive pulse when I touch its antenna (the base of a lamp). But after the Schmitt I'm darned if I can get the 4013 bistable to toggle reliably.
My next step will be to try adding a monostable (another half
4001/4011). But I'm wondering if that's possible with just the 4013, using both halves, which would be neater. (There's little room in the base of this lamp.)
Failing that I'll probably adapt a slightly more complex push-button toggle circuit from Bill Bowden I've used reliably a couple of times in the past.
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Any and all suggestions welcome please.
P.S: Anyone use this web site from an iPad? That's what I used for my earlier attempts to post this (rather than my email/newsreader which I'm now using).
Are you saying the pulse looks "noisy and slow" _after_ the Schmitt?
Post a schematic.
...Jim Thompson
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| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: skypeanalog | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
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I love to cook with wine. Sometimes I even put it in the food.
One typically would want a LONG pulse to be required for the touch recognition, and a fast rise/fall pulse to clock the flipflop. It makes sense to use a monostable, AND'ed with the touch output, and only to clock when the full monostable period (tenth of a second?) coincides with touch-always-present. A hex Schmitt inverter (74HC14 or 4584), with diodes, resistors, capacitors, can do the gate/Schmitt/monostable parts.
Hi Jim. Please see earlier screenshot and subsequent schematic in my other thread, 'Why cap needed at Schmitt output?', which is focusing on my current circuit problem.
In THIS thread I'm hoping to get recommendations for alternative toggle circuits, for future consideration.
I think you'd probably be better off just buying a touch chip, say that Microchip MTCH101 that someone else referenced. ...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: skypeanalog | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
Thanks. Will pursue that. In fact I *think* that chip may have been the one used in the touch lamp I'm trying to replace. Bulb blew and apparently fried the chip.
Please see earlier screenshot and subsequent schematic in my other thread, 'Why cap needed at Schmitt output?', which is focusing on my current circuit problem.
In THIS thread I'm hoping to get recommendations for alternative toggle circuits, for future consideration. Not just touch switch activated but versatile toggle circuits for general use.
The one I posted in ABSE uses 4066 switches for some reason (I guess he had some left over) but they are just used as inverters and you could make the same thing with ordinary NOT gates.
Haven't seen it appear on ABSE :-( ...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: skypeanalog | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: skypeanalog | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
I remember a thread from 15 years ago where Spehro and others posted various examples, but there is no searchable usenet archive any more.
I specifically remember Spehro coming up with one he called his new favorite. It was just a D flip flop and a few passives.
Of course there is the ORIGINAL toggle circuit. I tried this with 12 volt relays and it needed 15 volts, so I added the resistor and it worked down to 10.5V.
Tom, I can't see anything relevant in sci.electronics.basics. Is that what you mean by 'ABSE'?
Can you post a link or a subject name?
I've just about finished construction of the touch activated lamp (but with a last minute additional puzzle over 'earthing', about which I'll post sep arately) but I've incorporated easy access to +V, 0V and the touch switch s ection output. So I can experiment later with alternative toggle circuits f or slow rise time inputs.
Jim, Re your problem over seeing my messages. I'm posting in three ways:
From my PC newsreader program, Forte's Agent, to the sci.electronics.des ign newsgroup.
From my PC browser, Firefox, to the Google 'group' sci.electronics.desig n, which I assume to be effectively a web version of the newsgroup, identic al in content but perhaps not in timing.
Here it is, reposted to the S.E.D/Schematics Page of my website...
It apparently got dropped during a housecleaning where I deemed it without enough explanation to stand on its own.
What it is, but in switch format, is how CMOS master-slave flip-flops work... blazingly faster than gate-derived versions.
I also found my inverter version, maybe I'll write it up as a set. ...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: skypeanalog | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
Hi Terry. Surely you remember the lengthy thread we had on s.e.d. in 2002, on single pushbutton toggle circuits. I enhanced one of the better ones for our book, see Figure 3.99 page 196. It features zero-power when in the off state.
Bill Bowden's 2001 web page helped start us off:
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High Current MOSFET Toggle Switch with Debounced Push Button, adapted from "Toggle Switch Debounced Pushbutton" by John Lundgren
There were 164 posts on s.e.d. in 2002, with the subject "zero-power toggle circuit".
Win's 2016 comment: In all of the circuits below the output power switch is a weak point. It's preferable to use a protected high-side power-switch IC, see Table 12.5, page 826. Many of these ICs have low quiescent current draws, and some that use p-channel switches, are zero.
OK, let's take a quick look through these 164 posts, and a few others as well.
Certainly the part values are not optimum. For example, currents could be scaled down 10x, increasing all R's by 10 and C1 = 0.1uF ceramic. Q2 can be almost any n-channel MOSFET, small to large.
2002, "Wafer", in "zero-power toggle circuit" thread. ASCII drawn by Win Hill, with reduced resistor values, further improved by Fred Bloggs.
From: Tony Williams There's a spare inverter in that 4007A Fred. Might as well make it earn its keep. Strap it's input in parallel with the input of the right-hand inverter in the above circuit. Then two choices of what to do with the new o/p.
a) Strap it in parallel with the present o/p, for increased output drive.
b) Dedicate it to driving the 15k, so that the feedback is totally independant of the load.
Might be >
From: Winfield Hill Or use a 4069 and have four spare inverters. :)
Hi Fred. When I get back to my PC (I'm sending this from iPad) I'll try to find or redraw its schematic. It's a circuit I've used several times, proba bly starting around 1985.
But, despite my earlier optimism, this particular project is proving more d ifficult than I expected. I finally had it working OK on the bench, on Vero board, using my bench power supply. Then added its own independent supply (
12V as before) and to my surprise the touch section now produced no signal. Eventually fixed that by swapping the 2-core mains cable for 3-core and co nnecting the earth wire to 0V of my circuit. But puzzled why this proved ne cessary.
Anyway, on heat-shrinking the bits and stuffing them carefully into the me tal lamp base (which serves as the touch area) the darned thing became erra tic, with the touch section frequently oscillating when not touched. The pr oximity of the components to each other and to the metal base, miniature tr ansformer and relay is an issue I'd been apprehensive about, and apparently that was justified!
I'm considering various options, (as well as yielding to my wife's remonstr ations to "Let's just buy another lamp"). Such as adding a smoothing filter and then maybe following that with a monostable rather than my 4001 Schmit t. But it looks like I'll have to abandon this capacitive type and look for an entirely different touch circuit. Perhaps one that will pick up mains h um when I touch the base.
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