photo sensor ignition - Page 1
Forum section: electronics / projects

author: tomcer34
author_rank: Contributor
timestamp: January 20, 2022, 05:34:33 pm
content: hi, I want to replace hall sensor from my ignition to for some photo sensor. Can u suggest me some fast one? More then 30kHz. Reason for replacing hall sensor it´s because it´s too slow for me.Thank u for help!

author: Benta
author_rank: Super Contributor
timestamp: January 20, 2022, 09:33:25 pm
content: A one-cylinder 2-stroke engine rotating at over 1.000.000 rpm? Or a 12-cylinder rotating at over 80.000 rpm?

author: CaptDon
author_rank: Super Contributor
timestamp: January 21, 2022, 04:47:57 pm
content: We use hall effect sensors in turbochargers giving 8 pulses per revolution and the turbos run at a max of 28,000 rpm. Our sensors don't lag at all. Why do you feel your sensors aren't fast enough? Probably the crappy circuit surrounding your sensor maybe? We run dynamic compression on the incoming signal to keep it leveled in amplitude then hit a high gain limiter/clipping stage to form a square wave whose leading edge remains relatively accurate in phase relationship to the 8 teeth on the shaft. This whole mess is used with a pair of X/Y accelerometers to accomplish precision balancing of turbocharger compressors and turbines. It is real cool when 50 pounds of 28,000 rpm rotating mass comes apart!!! I've seen the pieces go through 1/4" steel plate! 8 pulses per revolution at 28,000 rpm is still only 3740 hertz. Why in the world do you need resolution at 30Khz??

author: Terry Bites
author_rank: Super Contributor
timestamp: January 21, 2022, 06:24:29 pm
content: Rise times are in the uS or nS for hall sensors. How many Mhz do you need?

author: floobydust
author_rank: Super Contributor
timestamp: January 21, 2022, 07:20:52 pm
content: Optical switches do not do well in vehicle/automotive applications- if the dirt doesn't contaminate them, the heat or moisture does.You are very hard pressed to find slotted optical switches that areAEC-Q102qualified. I think they aren't reliable- can't seal them due to moving parts, temperature cycles or the heat are very harsh and CTR degrades as they rapid age.Chevy 90's LT1 Optispark was a flop for all the reasons I've listed.I notice more automotive racing distributors are using optical pickups, which surprises me but there is much less sensitivity to EMI.Most are primitive 8-slot like Mallory Unilite, using 5mm LED/photo-transistor.The MSD (pic) looks totally overboard with what 1,024 slot wheel? Silly because the slop in timing chain and distributor gears makes that pointless (pun intended).A crankshaft 60-tooth pickup is fine. Unless a one or two cylinder engine, because they have huge variations in crank velocity an ECU can make timing errors generating the next spark or fuel injection event. A V-twin is terrible, the crank slows down during a compression stroke, speeds up after ignition, but a misfire can happen and the 45° firing interval Harley riders love makes it rough to follow to estimate spark timing.

author: tomcer34
author_rank: Contributor
timestamp: January 22, 2022, 10:20:16 am
content: Hi, there is my schematic. It´s my own design so it´s very possible that there are few mistakes. For hall sensor I´m using 55100-3H-02-A. I couldn´t upload my schematic here, because it´s in Eagle and this page doesn´t support that format. So reason for optical sensor is that i can´t rev my engine more than 2000 RPM rignt now with this setup(with my old thyristor ignition i can go to 13500RPM). When i check with my osciloscope i can see 700Hz frequency going from hall sensor. I need high freqency for precission of igniton. 55100-3H-02-A should be capable of 10kHz but i cound managed it. btw those two imputs from lm339 are for 1 hall sensor and second for optical sensor.

author: tomcer34
author_rank: Contributor
timestamp: January 22, 2022, 10:22:24 am
content: it´s one cylinder two stroke engine. And max rpm is around 13500. High freqency of sensor is for precission and now max rpm

author: tomcer34
author_rank: Contributor
timestamp: January 22, 2022, 10:24:45 am
content: What sensor are u usnig? I´m running 55100-3H-02-A for now. Also could u send me diagram for it? down there I send my.

author: NiHaoMike
author_rank: Super Contributor
timestamp: January 22, 2022, 01:52:25 pm
content: Have you considered inductive sensors? Not much to go wrong with simple coils of wire and their low cost makes it trivial to have multiple for redundancy.

author: floobydust
author_rank: Super Contributor
timestamp: January 22, 2022, 06:07:15 pm
content: I think your circuit has a few mistakes that would make it work poorly. 555 output pin 3 needs base-drive resistor for Q4, otherwise you're overloading it. I would use around 330R. Tie pin 4 to pin 8, tie unusedLM339inputs to gnd. 7805 output should have bulk cap at least 10-22uF. Usually a capacitor is across R11 for noise. R9 is 10k? R17 is low, 520R it could be 10k 555 triggers on falling edge so speed loss not important.The Littelfuse Hall sensor55100-3H-02-Arated 12kHz, open-collector output to ... pad 8 right.Slotted optical switches not always fastVishay TCPT1300seems relatively slow 20-150usec rise/fall times.

author: tomcer34
author_rank: Contributor
timestamp: January 31, 2022, 07:23:29 pm
content: this is my new revision. Few mistakes were corrected, now i can rew up to 5k rpm, but it´s still not enought. Do u have any suggestion where problem might be? thank all of u for ur time

author: langwadt
author_rank: Super Contributor
timestamp: January 31, 2022, 07:46:34 pm
content: Quote from: tomcer34 on January 22, 2022, 10:22:24 amone cylinder two stroke at 13500rpm is 225Hz ...

author: tomcer34
author_rank: Contributor
timestamp: January 31, 2022, 08:13:16 pm
content: Quote from: langwadt on January 31, 2022, 07:46:34 pmyes, but i need exact impuls, when piston is at the top, that´s why i need high frequency. With 225Hz it would need to be same rpm whole time and that´s not possible. I need at least 10kHz for good timing of my igniton

author: tomcer34
author_rank: Contributor
timestamp: January 31, 2022, 08:16:24 pm
content: Quote from: NiHaoMike on January 22, 2022, 01:52:25 pmyes, it was originaly there, but i had problems with reading and converting it to digital. There was around 60V and also negative voltage. so my tranzistors were not happy even with 100k rezisotor. Bike I´m working on is jawa babetta 210 typ 50

author: tomcer34
author_rank: Contributor
timestamp: January 31, 2022, 08:20:30 pm
content: Quote from: CaptDon on January 21, 2022, 04:47:57 pmcan u suggest or send some diagrams please. I want to improve my own designt based on someting working. On intertnet is not mutch about this topic

author: Benta
author_rank: Super Contributor
timestamp: January 31, 2022, 08:28:46 pm
content: Quote from: tomcer34 on January 31, 2022, 08:16:24 pmInstead of reinventing the wheel, I'd have kept that and done something with the signal conditioning instead. Just because a couple of transistors were unhappy there's no reason to go over the top. That can be solved.

author: eugene
author_rank: Frequent Contributor
timestamp: January 31, 2022, 11:19:05 pm
content: I'm confused by the application. Here's what I am guessing:The crankshaft position sensor outputs are connected to the inputs of the LM339 comparator (PAD8 and PAD13.)The 555 generates a pulse of defined period that is used to trigger the ignition module.The ignition module is connected to the open collector Q4 (PAD12.)Is this correct? If so, how do you control the spark timing? Do you just fire at top dead center (TDC) under all conditions of throttle and RPM?

author: tomcer34
author_rank: Contributor
timestamp: February 01, 2022, 08:03:03 pm
content: Quote from: eugene on January 31, 2022, 11:19:05 pmbasicaly yes, pad 8 is for hall effect sensor and pad 13 is for second one/optical sensor(only for experiment right now). Pad 12 is for igniton coil. right now sparks fire where is sensor possiotion on crank, but in the future it will be controled by arduino(it will shift spark timing by couple of degrees depended on the load and rpm, that part sort of work, but this doesn´t). sorry for confusing diagram/schematic but it´s made for pcb production.

author: tomcer34
author_rank: Contributor
timestamp: February 01, 2022, 08:09:01 pm
content: Quote from: Benta on January 31, 2022, 08:28:46 pmwhat do u mean by that? what´s that can be achived? Do u have some example please?

author: langwadt
author_rank: Super Contributor
timestamp: February 01, 2022, 08:11:21 pm
content: Quote from: tomcer34 on February 01, 2022, 08:03:03 pmjust a bare ignition coil and that wimpy 100mA transistor?

author: Benta
author_rank: Super Contributor
timestamp: February 01, 2022, 08:43:46 pm
content: Quote from: tomcer34 on February 01, 2022, 08:09:01 pmI mean that: if your electronic circuit is so sensitive that it it will not work in an automotive application (motorbikes are part of this), you'll never get anything to work.Spikes, noise, high voltages are standard.The original magnetic sensor was probably the best solution, but was incompatible with your apparently very sensitive circuit.80% of automotive (motorbike) design is dealing with an electrically very harsh environment.

author: viperidae
author_rank: Frequent Contributor
timestamp: February 01, 2022, 09:15:51 pm
content: Does the signal disappear when you reach the 5k rpm limit you currently have, or is the ignition timing too retarded the rev higher than that?The faster the engine spins, the more you need to advance timing, yes? Especially if your trigger signal includes the fixed dwell time.Modern ECUs keep their own internal crank position and sync it to the crank position input. That way the ignition timing can be much more precise than the crank sensor. You'll be able to apply the correct dwell for the coils so they have enough energy to fire.

author: floobydust
author_rank: Super Contributor
timestamp: February 01, 2022, 09:56:59 pm
content: It would help if we knew what engine this is going on, a moped or what and what the original ignition system was. No idea what OP is using for the magnet either. How about some pictures. Otherwise this guessing is just silly.Simple ignition systems have irregular cam lobe and staggered pickup coils to achieve timing advance and rev limiting.

author: tomcer34
author_rank: Contributor
timestamp: February 02, 2022, 05:42:44 pm
content: Quote from: langwadt on February 01, 2022, 08:11:21 pmSorry, my mistake, i dont use BC547, it´s there because i dont have library for tranzistor im using, it was just same footprint. Tranzistor that is used is E19009-2

author: tomcer34
author_rank: Contributor
timestamp: February 02, 2022, 05:48:54 pm
content: Quote from: Benta on February 01, 2022, 08:43:46 pmit´s not that sensitive. casing is shielded. Osciloscope didn´t show any high voltage spikes or anything, signal is clean. Problem is that pull rate of hall senosor is too low(on scope 1.5kHz right now, but datasheet says it should be 12kHz).

author: Benta
author_rank: Super Contributor
timestamp: February 02, 2022, 06:01:54 pm
content: "it´s not that sensitive. casing is shielded. Osciloscope didn´t show any high voltage spikes or anything, signal is clean. Problem is that pull rate of hall senosor is too low(on scope 1.5kHz right now, but datasheet says it should be 12kHz)."That's somewhat in contrast to this statement from you:Quote from: tomcer34 on January 31, 2022, 08:16:24 pmSo what's true?

author: tomcer34
author_rank: Contributor
timestamp: February 02, 2022, 06:27:15 pm
content: Quote from: floobydust on February 01, 2022, 09:56:59 pmthere is original diagram of it. It is simple tyristor ignion system. Mopped is Jawa 210. It´s two stroke 50cc engine that has been modify. I don´t need a rev limiter.there is few phtotos and pictures. If u would need more, let me know

author: tomcer34
author_rank: Contributor
timestamp: February 02, 2022, 06:37:05 pm
content: Quote from: Benta on February 02, 2022, 06:01:54 pmthat was for induction sensor. Signal is perfect, as i said, but pulling rate of hall effect sensor is low and i dont know why. By qoute " i had problems with reading and converting it to digital" i ment, when i was usinginductiontype sensor, that was originaly there, i had problems with unpredictable voltage. right now it´s based on hall sensor. Sorry for confussion i made. My english is not the best

author: eugene
author_rank: Frequent Contributor
timestamp: February 02, 2022, 11:06:53 pm
content: Variable reluctance sensors require special signal conditioning. Typically, they look for a zero crossing.Either Hall Effect or optical sensor should be fast enough. If there is a time delay that is constant under all conditions, then that can be compensated for in the microcontroller.My guess is that the engine will not rev above 5k RPM because the spark timing is not advanced far enough, not because the crankshaft position sensor is too slow.

author: langwadt
author_rank: Super Contributor
timestamp: February 02, 2022, 11:43:35 pm
content: Quote from: eugene on February 02, 2022, 11:06:53 pmI know I guy that has been building ECUs for probably 30 years, I think most of his designs use a resistor into a 74hc14 biased to VCC/2 with another resistor as signal conditioning and that works with pretty much any sensor VR or HallQuote from: eugene on February 02, 2022, 11:06:53 pmyeh, the original ignition looks mostly like capacitor discharge, so the advance is pretty much fixed at any RPMwith a sensor into a 555 for dwell time flyback, the ignition will be retarded with increasing RPM

author: floobydust
author_rank: Super Contributor
timestamp: February 03, 2022, 02:28:15 am
content: Small engines use the magnetic circuit to achieve timing advance in firing the SCR. There's likely more than one magnets in the flywheel as well. OP did not give info about whatever the Hall sensor is picking up.Running an inductive sensor into a Schmitt trigger does not work well, especially with VR you get a phase shift with speed and need compensation which automotive VR sensors incorporate. It would be OK with a digital (Hall) sensor though.pic fromSilicon Chip Magazine

author: langwadt
author_rank: Super Contributor
timestamp: February 03, 2022, 02:47:11 am
content: Quote from: floobydust on February 03, 2022, 02:28:15 amjust just fine with VR crank and ABS sensor and hall cam sensors

author: floobydust
author_rank: Super Contributor
timestamp: February 03, 2022, 02:56:56 am
content: A VR position sensor and a speed sensor are different i.e.MAX9924 Variable-Reluctance Sensor Interfaceincludes Adaptive Peak Threshold for the threshold shift. Without it you'll get a phase shift which is bad for timing, and not important for speed sensing like ABS.It also depends on how many teeth you're dealing with.

author: langwadt
author_rank: Super Contributor
timestamp: February 03, 2022, 03:47:06 am
content: Quote from: floobydust on February 03, 2022, 02:56:56 amexcept at starting the voltage is tens of volts, all you want is the zero crossing. And if there is any speed dependent shift it will be incorporated in you ignition map

author: tomcer34
author_rank: Contributor
timestamp: February 03, 2022, 01:47:43 pm
content: Quote from: eugene on February 02, 2022, 11:06:53 pmtiming is on spec with original ignition. i tried a lot of possitions. Stock work the best. I even tried extreme of both timings. Ignition timming in high rpm will be done with another NE555 and digital potenciometer and arduino. That part of my project works well, only 6ns delay and in engine it doen´t mean any difference. But now it´s not part of schema/diagram, right now it´s not used, because I tried deleting any possible mistakes, but this was not one of them.

author: tomcer34
author_rank: Contributor
timestamp: February 03, 2022, 01:54:40 pm
content: Quote from: langwadt on February 02, 2022, 11:43:35 pmi didn´t notice any dwell time flyback. Any delay in circuit is around 6ns as far as i messured. Timing is on the spot (1.5mm before top to be exact). But hall sensor can react fast enought in changing magnetic fields. Also as u said, in original ignition advence of timing was fixed, also right now it´s fixed in all frequency i messured. Measuring was done with Hz generator to remove possible mistakes I coud make with hall sensor. Right now i need spark to fire when it´s need to be fired

author: tomcer34
author_rank: Contributor
timestamp: February 03, 2022, 01:58:23 pm
content: Quote from: floobydust on February 03, 2022, 02:28:15 amhall sensor is picking up original magnet on flywheel, also hall sensor is in the same possiton as was original induction sensor used with tyristo igniton. Hall sensor that i´m using should be digital acording to datasheet. but there is a few version of it so i may be wrong, but also i used comparator to realy make it to digital signal

author: tomcer34
author_rank: Contributor
timestamp: February 03, 2022, 01:59:39 pm
content: Quote from: langwadt on February 03, 2022, 03:47:06 amso i have a wrong sensor for my project ?

author: floobydust
author_rank: Super Contributor
timestamp: February 04, 2022, 09:34:46 pm
content: I don't think there's anything wrong with the Hall sensor and you can run the same sensor off some magnets on a hand drill or fan to prove it. The Hall sensor already has a comparator so the LM339 is not needed for it.Or you have a noisy 5V causing trouble, or the other coils (CDI and lighting) and magnets are causing side-effects. The Hall sensor wants the magnet perpendicular to its face, not parallel to it so is it even oriented properly?But maybe the circuit's approach is not going to work?First, the 555 is a fixed pulse-width (dwell) time- which does not cover both low speeds and high speeds.You need the coil energized, storing energy BEFORE the spark event. The CDI module does this by storing energy in a HV capacitor.A good dwell time at low speeds means the 555 cannot re-trigger at high speeds, there is no time. So it will stay on and there is no spark. Is this what is actually going on?This is a small 2-stroke engine, I would think it really needs timing advance. Here some 50cc are limited to 30MPH.edit: the rotor seems to have 7 magnets- 6 are for lighting and CDI power, and one just for ignition timing.

author: tomcer34
author_rank: Contributor
timestamp: February 05, 2022, 08:45:19 pm
content: Quote from: floobydust on February 04, 2022, 09:34:46 pm5V it´s checked and it´s clear with new caps. Hall sensor is oriented properly and picking only timing magnet.i used 8600uF cap bank made from smaller caps, so there is energy before spark.u may be right with ne555 re-triggering. When is NE555 oscilating at 10kHz circuit act diffrently, but there high Hz cant take my ignition coil. So there goes project. never mind. Is there way i could used this circuit, but insted of "turnig on and off" NE555, turnig off and on something different? for example tranzistor for ignition, but NE555 would be still oscilating, or adding one more tranzistor before existing one. i will put picute to see what i mean. i need to get this working and remaking this is not possible, because deadline in school is 11.2 XD

author: langwadt
author_rank: Super Contributor
timestamp: February 05, 2022, 09:10:22 pm
content: Quote from: tomcer34 on February 05, 2022, 08:45:19 pmgotta show how you have it all connected, 8600uF makes no sense it's probably a few uF in the original thyrister ignition

author: eugene
author_rank: Frequent Contributor
timestamp: February 05, 2022, 09:45:23 pm
content: If you are going to use an Arduino for timing, why not use it to generate the pulse dwell too?555's seem great when there is no other way. But Arduino is an easier way.

author: tomcer34
author_rank: Contributor
timestamp: February 06, 2022, 03:00:25 pm
content: Quote from: eugene on February 05, 2022, 09:45:23 pmi didnt want to risk damaging my arduino when i was strating this and after a while it was easier to let it sit there. But i will try it with arduino now.

author: tomcer34
author_rank: Contributor
timestamp: February 06, 2022, 03:09:11 pm
content: Quote from: langwadt on February 05, 2022, 09:10:22 pmoriganly there was 4uF, but i made it to 8600uF because it was pulling too mutch current and it made my voltage regulation nightmare. But with this huge capacitance, is voltage regulation "perfect", no huge spikes or drops in voltage, 30mV at most. There is my PCP layout. Tranzistor and caps are on another board(handmade) so there would be less noise, to base of tranzistor is going shielded wire(from brokend osciloscope probe). And, is arduino fast enought for 12000RPM, time to react to hall sensor and send signal to the tranzistor?