Guessing usually doesn't do much. You need a oscilloscope to see what is actually going on with the signal. I have several but my current fave is the DPScope. Possibly cheaper than destroying a bunch of stuff...
Rev counter/tachometer pulse reduction (divide by 2)
- Thread starter samis_p
- Start date
4 out of 10 for helpfullness dippy, thanks. 1) my gauge is reading twice what it should as i have the original tach which is telling me so. 2) with just the flip flop connected on its own the reading is erratic and from reading this topic i have come to the conclusion that noise or voltage spikes can be the cause, hence the need for caps, resistors and diodes on the input signal. 3) didn't know about rev-ed so thanks for that. 4) i have tried rs components but there are so many types i need pointed in the right direction (my main reason for posting). 5) no scope, i just want to give the suggested circuits a go as the problem i have is identical to the op so his cure should remedy my issue. 6) the signal comes from the dizzy (relevant?). 7) just because you use lots of punctuation, doesn't mean your grammar is good.
the speedo/tach. http://www.ebay.co.uk/itm/190765075838?ru=http://www.ebay.co.uk/sch/i.html?_from=R40&_sacat=0&_nkw=190765075838&_rdc=1
and i have the flip flop connected like so. http://www.doctronics.co.uk/images/4013_04.gif
s and r are grounded and have the positive to 12v feed and earth grounded also.
thanks
and i have the flip flop connected like so. http://www.doctronics.co.uk/images/4013_04.gif
s and r are grounded and have the positive to 12v feed and earth grounded also.
thanks
Is the "12V feed" to the logic chip straight from vehicle supply without any protection/filtering?
And is the 'signal' straight from points terminal of an old-fashioned distributor? (I assume that's what "dizzy" means?).
Does the signal have any isolation, limiting or filtering?
Can you tell us the drive required by the tachometer section of this device?
What I am trying to get is the circuitry you have used with your flip-flop.
Chucking the signal straight into a logic chip without any input (and possibly output) buffering is asking for trouble.
And you can kill a chip unless your supply is good. Decoupling is recommended in most cases.
What flip-flop are you using? Have you read the Data Sheet?
Which PICAXE are you using and what will it be doing?
And is the 'signal' straight from points terminal of an old-fashioned distributor? (I assume that's what "dizzy" means?).
Does the signal have any isolation, limiting or filtering?
Can you tell us the drive required by the tachometer section of this device?
What I am trying to get is the circuitry you have used with your flip-flop.
Chucking the signal straight into a logic chip without any input (and possibly output) buffering is asking for trouble.
And you can kill a chip unless your supply is good. Decoupling is recommended in most cases.
What flip-flop are you using? Have you read the Data Sheet?
Which PICAXE are you using and what will it be doing?
Quicker towards what?snip
thanks for the diagrams, i shall persue this one alone, it will be quicker that way.
A solution or more problems?
Seriously,
there are many qualified experienced people
on this Forum.
They really can help.
But, for your own sake, please provide more information.
e
Unless this is a one off venture into electronics - GET ONE (0r find someone that has one)! Doing this sort of work without one is literally shooting in the dark.5) no scope
Since it appears there is NO Picaxe related vector to your questions you are coming off as a very rude person. There are many here that can help but you need to provide adequate information in a reasonable way. At this point you need to provide a sketch of how you have hooked all your components up and make/model of the vehicle.
Insufficient information given. Decouple the power supply to your R-S flip-flop? Sure, but which R-S flip-flop do you have exactly? Add a filter to your signal line? Sure, but what is the nature of the signal to be filtered - sourced form real contact breaker points, or from an electronic coil drive, or a crank sensor pickup, or ...I JUST WANT INFORMATION ON THESE CAPACITORS FOR DECOUPLING!!!
You may have to.thanks for the diagrams, i shall persue this one alone, it will be quicker that way.
The makers of your panel offer support, quoting eBay
"If you have any problems in pre-sale, shipping and after-sale questions, you can reach us by eBay message"
but that too is likely to take much longer than the four hours you allowed for here.
Difficult to see why your speedo reads x2, did you order the panel to suit your motorcycle wheel size?
@mikko
Ok, it looks like you are using 1/2 of a CD4013 "D" flip-flop operating at 12v to divide the input signal by 2. This also means that the output of the 4013 will be a 12v square wave that a Picaxe cannot handle. However you have not indicated where a Picaxe comes in to your project. Is there a Picaxe chip involved in your project or do you just need electronics help?
You have asked what caps / diodes to use and where to get them based upon thew your assumption that noise is the culprit. However you have provided no information as to the source of the signal going to the CD4013 except it comes from a "dizzy" ,whatever that means. So, how can anyone make anything other than a blind guess as to what you may need without adequate information?
You might start by revealing the source of the input signal to the CD4013. Is it the coil trigger signal for a CDI ignition? Or something else?
Taking the time to draw up a complete schematic diagram of what you have so far and posting it here will help others to help you.
While this is a forum intended for things related to Picaxe Microcontrollers and Revolution Education products, many members are willing to help with non-Picaxe related electronics issues if adequate and clear/intelligible information is provided. This sometimes means posting a schematic or photo...
It may also mean using periods at the end of sentences and spaces between paragraphs as many members tend to avoid threads where the poster can't be bothered to at least attempt to use English / Grammar beyond a third grade level.
Ok, it looks like you are using 1/2 of a CD4013 "D" flip-flop operating at 12v to divide the input signal by 2. This also means that the output of the 4013 will be a 12v square wave that a Picaxe cannot handle. However you have not indicated where a Picaxe comes in to your project. Is there a Picaxe chip involved in your project or do you just need electronics help?
You have asked what caps / diodes to use and where to get them based upon thew your assumption that noise is the culprit. However you have provided no information as to the source of the signal going to the CD4013 except it comes from a "dizzy" ,whatever that means. So, how can anyone make anything other than a blind guess as to what you may need without adequate information?
You might start by revealing the source of the input signal to the CD4013. Is it the coil trigger signal for a CDI ignition? Or something else?
Taking the time to draw up a complete schematic diagram of what you have so far and posting it here will help others to help you.
While this is a forum intended for things related to Picaxe Microcontrollers and Revolution Education products, many members are willing to help with non-Picaxe related electronics issues if adequate and clear/intelligible information is provided. This sometimes means posting a schematic or photo...
It may also mean using periods at the end of sentences and spaces between paragraphs as many members tend to avoid threads where the poster can't be bothered to at least attempt to use English / Grammar beyond a third grade level.