On Friday, April 9, 2021 at 11:30:28 PM UTC-5, John Miles, KE5FX wrote:> I think he's trying to generate free energy through muon induction from the > spinning corpse of Bob Pease...No, just trying to come up with some things to sell. This is for a superior submersible flashlight.
Inexpensive nano power comparator needed
Started by ●April 8, 2021
Reply by ●April 10, 20212021-04-10
Reply by ●April 10, 20212021-04-10
On Saturday, April 10, 2021 at 10:01:42 AM UTC-5, jla...@highlandsniptechnology.com wrote:> Something like that. There is an infinite supply of no-name obnoxious > amateur googlegroopers who want free engineering and, probably, free > energy.I am not an amateur, and I don't think (hope) I am generally obnoxious. Since my funds are extraordinarily limited, I do need for things to be as economical as possible. As a former physicist, I am very well aware there is no such thing as energy for free. There is such a thing as free energy, as any physicist or physical chemist can tell you, but in that context, the word "free" has nothing to do with trying to get something for nothing. It has to do with whether a process can occur spontaneously or not.
Reply by ●April 11, 20212021-04-11
On 10/04/2021 5:30 am, John Miles, KE5FX wrote:> On Thursday, April 8, 2021 at 7:41:02 AM UTC-7, jla...@highlandsniptechnology.com wrote: >> Nope. You're on your own. > > I think he's trying to generate free energy through muon induction from the > spinning corpse of Bob Pease... > > -- john, KE5FX >I thought the OP was trying to flash a LED at low duty cycle? You and I might do that with 4-5 descrete transistors for less than the cost of a micropower comparator but the OP presumably has his reasons. piglet
Reply by ●April 12, 20212021-04-12
On Sunday, April 11, 2021 at 4:53:49 AM UTC-5, piglet wrote:> I thought the OP was trying to flash a LED at low duty cycle?That is correct. This circuit is designed to turn the flashlight on when a reflective target is placed in front of a TCRT5000L retroreflector and off when a non-reflective target is placed in front of the TCRT5000L. The intent is for the battery to last at least 6 months with an acceptably low amount of battery drain (less than 20% of full charge). This means the entire circuit must draw significantly less than 1 mA when off. In order to manage this, I employ a series of 7 pulses over a period of about 2ms to trigger the unit to switch on when the reflective target is in place. These pulses are created by a TLC555. The reset pin is driven by a pulse created by a very low duty cycle circuit which draws only a fraction of a uV and produces a 2ms pulse every few hundred ms. The circuit draws an average of about 85 uA, including the high current (~100 mA) pulses.> might do that with 4-5 descrete transistors for less than the cost of a > micropower comparator but the OP presumably has his reasons.If you can drive the TCRT500L near its maximum of 60 mA instantaneous current while still drawing significantly less than 200uA average using a few discrete transistors, I am all ears. I am using a 3.3V power supply in order to minimize the current, but 5V at about half the current would also be fine.
Reply by ●April 12, 20212021-04-12
rhor...@gmail.com <rhorerles@gmail.com> wrote:> On Sunday, April 11, 2021 at 4:53:49 AM UTC-5, piglet wrote: > > > I thought the OP was trying to flash a LED at low duty cycle? > That is correct. This circuit is designed to turn the flashlight on when a reflective target is placed in front of a TCRT5000L retroreflector and off when a non-reflective target is placed in front of the TCRT5000L. The intent is for the battery to last at least 6 months with an acceptably low amount of battery drain (less than 20% of full charge). This means the entire circuit must draw significantly less than 1 mA when off. In order to manage this, I employ a series of 7 pulses over a period of about 2ms to trigger the unit to switch on when the reflective target is in place. These pulses are created by a TLC555. The reset pin is driven by a pulse created by a very low duty cycle circuit which draws only a fraction of a uV and produces a 2ms pulse every few hundred ms. The circuit draws an average of about 85 uA, including the high current (~100 mA) pulses. > > > might do that with 4-5 descrete transistors for less than the cost of a > > micropower comparator but the OP presumably has his reasons. > > If you can drive the TCRT500L near its maximum of 60 mA instantaneous current while still drawing significantly less than 200uA average using a few discrete transistors, I am all ears. I am using a 3.3V power supply in order to minimize the current, but 5V at about half the current would also be fine.There are a lot of unstated assumptions in what you wrote. It seems that you want TCRT500L to pulse with about 1/1000 duty cycle at frequency of order 1 Hz. This is doable using RC oscilator and pulse forming circuit in something like 5-10 transitors. If R are high enough this control circuit will run on few microamps. But your circuit generates more complicated thing. More complicated waveforms are easily generated using MCU. AFAICS almost any MCU with low power modes should be able to generate required pulses using less then 10uA of current, some claim below 2uA for such use cases (of course you need to separately account for TCRT500L current). -- Waldek Hebisch
Reply by ●April 12, 20212021-04-12
On 12/04/2021 12:09 pm, rhor...@gmail.com wrote:> On Sunday, April 11, 2021 at 4:53:49 AM UTC-5, piglet wrote: > >> I thought the OP was trying to flash a LED at low duty cycle? > That is correct. This circuit is designed to turn the flashlight on when a reflective target is placed in front of a TCRT5000L retroreflector and off when a non-reflective target is placed in front of the TCRT5000L. The intent is for the battery to last at least 6 months with an acceptably low amount of battery drain (less than 20% of full charge). This means the entire circuit must draw significantly less than 1 mA when off. In order to manage this, I employ a series of 7 pulses over a period of about 2ms to trigger the unit to switch on when the reflective target is in place. These pulses are created by a TLC555. The reset pin is driven by a pulse created by a very low duty cycle circuit which draws only a fraction of a uV and produces a 2ms pulse every few hundred ms. The circuit draws an average of about 85 uA, including the high current (~100 mA) pulses. > >> might do that with 4-5 descrete transistors for less than the cost of a >> micropower comparator but the OP presumably has his reasons. > > If you can drive the TCRT500L near its maximum of 60 mA instantaneous current while still drawing significantly less than 200uA average using a few discrete transistors, I am all ears. I am using a 3.3V power supply in order to minimize the current, but 5V at about half the current would also be fine. >Ignoring the complication of a burst of 7 pulses here is a first pass illustrative sketch. With shown values should give approx 80us pulses every 80ms with LED current approx 100mA. Average supply current should be a little over 100uA. If you are going to simulate it you may need to start the supply from 0V rather than steady-state to help simulation astable startup. <https://www.dropbox.com/s/5yhm1ciy8hvlx6r/SED_LED_Flash.pdf?dl=0> NPN are gum drop type like 2N3904 and PNP 2N3906 etc etc. Change caps to 0.1uF will give approx 40us pulses every 40ms etc. piglet
Reply by ●April 12, 20212021-04-12
On Monday, April 12, 2021 at 10:00:44 AM UTC-5, anti...@math.uni.wroc.pl wrote:> There are a lot of unstated assumptions in what you wrote.No, there are not. I did not ask for a circuit design. I provided that. All I asked for was either a low cost comparator ( ~ $0.30 or less) that would work with Micro-Cap 12, or for someone to sim the circuit in their own software using an MCP6542. >It seems> that you want TCRT500L to pulse with about 1/1000 duty cycle atWell, 1/1000 would be nice, but the design offers about 0.44%. Anything under 1/200 should be fine.> frequency of order 1 Hz.That's a little too low. The switch should not take a full second to turn on or off. On the order of 50 - 100ms is good.> This is doable using RC oscilator and > pulse forming circuit in something like 5-10 transitors. If > R are high enough this control circuit will run on few microamps.A circuit employing 5 discrete transistors is not too bad. A circuit with 10 discrete transistors is getting to be a bit of a mess, especially since each component adds to the cost of assembly. I would absolutely rather have 2 comparators, a 555, and a handful of resistors than two or three dozen discrete components. There are a number of reasons why manufacturers employ ICs, rather than discrete components, you know. The design as-is only uses 28 components, mostly resistors. Unless you can show me differently, I submit any design employing only discrete components is going to have a much higher parts count, and probably be more expensive, provided the MCP6541 or an even less expensive comparator will work.> But your circuit generates more complicated thing. MoreHow is that, again?> complicated waveforms are easily generated using MCU. AFAICSSo now you are going from one extreme to the other. Zero integration to massive integration. There are plenty of applications where an MCU is all but essential, but this is not one of them, IMO. If I *WERE* to go that route, I would employ a more complex waveform and decode it on the other side. The TCRT500L has optical filters that make such complexity unnecessary, or so I hope.> almost any MCU with low power modes should be able to > generate required pulses using less then 10uA of current, > some claim below 2uA for such use cases (of course you need toAt a certain point, reducing the idle current has no significant impact on the average current, since the bulk of the current is delivered during the LED pulses. Below about 100 uA, the idle current is quite insignificant, and there is no real difference between 2uA and 100uA.
Reply by ●April 13, 20212021-04-13
piglet <erichpwagner@hotmail.com> wrote:> On 12/04/2021 12:09 pm, rhor...@gmail.com wrote: >> On Sunday, April 11, 2021 at 4:53:49 AM UTC-5, piglet wrote: >> >>> I thought the OP was trying to flash a LED at low duty cycle? >> That is correct. This circuit is designed to turn the flashlight on >> when a reflective target is placed in front of a TCRT5000L >> retroreflector and off when a non-reflective target is placed in front >> of the TCRT5000L. The intent is for the battery to last at least 6 >> months with an acceptably low amount of battery drain (less than 20% of >> full charge). This means the entire circuit must draw significantly >> less than 1 mA when off. In order to manage this, I employ a series of >> 7 pulses over a period of about 2ms to trigger the unit to switch on >> when the reflective target is in place. These pulses are created by a >> TLC555. The reset pin is driven by a pulse created by a very low duty >> cycle circuit which draws only a fraction of a uV and produces a 2ms >> pulse every few hundred ms. The circuit draws an average of about 85 >> uA, including the high current (~100 mA) pulses. >> >>> might do that with 4-5 descrete transistors for less than the cost of >>> a micropower comparator but the OP presumably has his reasons. >> >> If you can drive the TCRT500L near its maximum of 60 mA instantaneous >> current while still drawing significantly less than 200uA average using >> a few discrete transistors, I am all ears. I am using a 3.3V power >> supply in order to minimize the current, but 5V at about half the >> current would also be fine. >> > > Ignoring the complication of a burst of 7 pulses here is a first pass > illustrative sketch. With shown values should give approx 80us pulses > every 80ms with LED current approx 100mA. Average supply current should > be a little over 100uA. If you are going to simulate it you may need to > start the supply from 0V rather than steady-state to help simulation > astable startup. > > <https://www.dropbox.com/s/5yhm1ciy8hvlx6r/SED_LED_Flash.pdf?dl=0> > > NPN are gum drop type like 2N3904 and PNP 2N3906 etc etc. Change caps to > 0.1uF will give approx 40us pulses every 40ms etc. > > pigletNice. Here it is in LTspice: https://tinyurl.com/hazvjhfk -- The best designs occur in the theta state. - sw
Reply by ●April 13, 20212021-04-13
On 13/04/2021 4:24 am, Steve Wilson wrote:> piglet <erichpwagner@hotmail.com> wrote: > >> On 12/04/2021 12:09 pm, rhor...@gmail.com wrote: >>> On Sunday, April 11, 2021 at 4:53:49 AM UTC-5, piglet wrote: >>> >>>> I thought the OP was trying to flash a LED at low duty cycle? >>> That is correct. This circuit is designed to turn the flashlight on >>> when a reflective target is placed in front of a TCRT5000L >>> retroreflector and off when a non-reflective target is placed in front >>> of the TCRT5000L. The intent is for the battery to last at least 6 >>> months with an acceptably low amount of battery drain (less than 20% of >>> full charge). This means the entire circuit must draw significantly >>> less than 1 mA when off. In order to manage this, I employ a series of >>> 7 pulses over a period of about 2ms to trigger the unit to switch on >>> when the reflective target is in place. These pulses are created by a >>> TLC555. The reset pin is driven by a pulse created by a very low duty >>> cycle circuit which draws only a fraction of a uV and produces a 2ms >>> pulse every few hundred ms. The circuit draws an average of about 85 >>> uA, including the high current (~100 mA) pulses. >>> >>>> might do that with 4-5 descrete transistors for less than the cost of >>>> a micropower comparator but the OP presumably has his reasons. >>> >>> If you can drive the TCRT500L near its maximum of 60 mA instantaneous >>> current while still drawing significantly less than 200uA average using >>> a few discrete transistors, I am all ears. I am using a 3.3V power >>> supply in order to minimize the current, but 5V at about half the >>> current would also be fine. >>> >> >> Ignoring the complication of a burst of 7 pulses here is a first pass >> illustrative sketch. With shown values should give approx 80us pulses >> every 80ms with LED current approx 100mA. Average supply current should >> be a little over 100uA. If you are going to simulate it you may need to >> start the supply from 0V rather than steady-state to help simulation >> astable startup. >> >> <https://www.dropbox.com/s/5yhm1ciy8hvlx6r/SED_LED_Flash.pdf?dl=0> >> >> NPN are gum drop type like 2N3904 and PNP 2N3906 etc etc. Change caps to >> 0.1uF will give approx 40us pulses every 40ms etc. >> >> piglet > > Nice. Here it is in LTspice: > > https://tinyurl.com/hazvjhfk > > >Thanks Steve, that gets me to a google drive link that wants a login? That two transistor complementary oscillator has a 1960s feel to it but works well in low power applications like this because most of the time both devices are non-conducting. piglet
Reply by ●April 13, 20212021-04-13
piglet <erichpwagner@hotmail.com> wrote:> On 13/04/2021 4:24 am, Steve Wilson wrote: >> piglet <erichpwagner@hotmail.com> wrote: >> >>> On 12/04/2021 12:09 pm, rhor...@gmail.com wrote: >>>> On Sunday, April 11, 2021 at 4:53:49 AM UTC-5, piglet wrote: >>>> >>>>> I thought the OP was trying to flash a LED at low duty cycle? >>>> That is correct. This circuit is designed to turn the flashlight on >>>> when a reflective target is placed in front of a TCRT5000L >>>> retroreflector and off when a non-reflective target is placed in >>>> front of the TCRT5000L. The intent is for the battery to last at >>>> least 6 months with an acceptably low amount of battery drain (less >>>> than 20% of full charge). This means the entire circuit must draw >>>> significantly less than 1 mA when off. In order to manage this, I >>>> employ a series of 7 pulses over a period of about 2ms to trigger >>>> the unit to switch on when the reflective target is in place. These >>>> pulses are created by a TLC555. The reset pin is driven by a pulse >>>> created by a very low duty cycle circuit which draws only a fraction >>>> of a uV and produces a 2ms pulse every few hundred ms. The circuit >>>> draws an average of about 85 uA, including the high current (~100 mA) >>>> pulses. >>>> >>>>> might do that with 4-5 descrete transistors for less than the cost >>>>> of a micropower comparator but the OP presumably has his reasons. >>>> >>>> If you can drive the TCRT500L near its maximum of 60 mA instantaneous >>>> current while still drawing significantly less than 200uA average >>>> using a few discrete transistors, I am all ears. I am using a 3.3V >>>> power supply in order to minimize the current, but 5V at about half >>>> the current would also be fine. >>>> >>> >>> Ignoring the complication of a burst of 7 pulses here is a first pass >>> illustrative sketch. With shown values should give approx 80us pulses >>> every 80ms with LED current approx 100mA. Average supply current >>> should be a little over 100uA. If you are going to simulate it you may >>> need to start the supply from 0V rather than steady-state to help >>> simulation astable startup. >>> >>> <https://www.dropbox.com/s/5yhm1ciy8hvlx6r/SED_LED_Flash.pdf?dl=0> >>> >>> NPN are gum drop type like 2N3904 and PNP 2N3906 etc etc. Change caps >>> to 0.1uF will give approx 40us pulses every 40ms etc. >>> >>> piglet >> >> Nice. Here it is in LTspice: >> >> https://tinyurl.com/hazvjhfk >> >> >> > Thanks Steve, that gets me to a google drive link that wants a login? > > That two transistor complementary oscillator has a 1960s feel to it but > works well in low power applications like this because most of the time > both devices are non-conducting. > > pigletThanks. I thought I had enabled sharing, but there is a separate procedure to follow that is new. I checked the file. It should work now. Ignore the signin link in the upper right. Let me know if you find any more problems. -- The best designs occur in the theta state. - sw
