Electronic pointer tachometer for motorcycle

jaclew 13344 16
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  • Already a few years ago I made an analog electronic tachometer (with a tip) and it works without problems in my motorcycle
    enduro which is Yamaha XT600, type 3TB, year 1995.
    I think that since the design has proven itself "in battle" it will be worth presenting it here.
    Why did I make such a modification? Mainly due to the fact that the old mechanical indicator was driven by a cord
    from the worm gear in the engine head. Often there was an unsealing of the O-ring which caused oil leaks,
    and the link itself also disappointed. The original one is expensive and the poor quality substitutes have not lasted even one season.

    I show below step by step how the design and implementation went, I attach a diagram with the values of the elements,
    so almost complete data to make such a tachometer on your own.
    Almost, because I do not show here the PCB pattern due to the fact that it is dimensioned for the specific housing of my old original meter.
    In addition, whoever wants to can use the ready tachometer module and as such adapt it to their needs.
    I downloaded the two most important components from it: the CS8190 integrated circuit and the air-core tip drive, and I've done the rest myself.
    I will write about this module later.

    In this forum, in the automotive section, there is the topic "Tachometer in a moped":
    Tachometer in a moped
    but dozens of answers do not consistently present one concept of the device there, and when the thread of the tachometer module similar to the one described here appears, there is no meaningful explanation of the changes needed to adapt it to specific requirements.
    Therefore, I think that here - in the DIY department - showing your own solution will be appropriate and welcome :-)

    Well, then.
    Modifications were made on a motorcycle with a four-stroke, single-cylinder engine, TCI ignition controlled by a microprocessor. It supplies one coil and one spark plug.
    Oscilloscopic measurement showed that the ignition module gives one impulse for every revolution of the crankshaft.
    This is how the oscillogram looks like when the engine is idling (about 1500 rpm):
    Electronic pointer tachometer for motorcycle

    I used the original housing of the tachometer because it also has control lamps.
    The dial, which was also preserved, was illuminated by a W5W bulb, but it did not look good.
    I decided to change it too.
    The maximum reading of the original tachometer is 9000 rpm with a pointer angle of 180 degrees.
    It looked like this:
    Electronic pointer tachometer for motorcycle
    I bought a cluster of clocks from Polonez for 20 zlotys and got a tachometer from it (Lumel MS14)
    It is built on the basis of the CS8190 system, which controls the air-core drive. It looks like this:
    Electronic pointer tachometer for motorcycle
    As I have already mentioned, the module on the board can be adapted by appropriate selection of elements to suit the tachometer's own design.
    Air-core itself is easily removable from the plate (four M3 screws) and most importantly - with a relatively hard return spring on the axle.
    Thanks to this, it is more resistant to shocks, after all, it was in the Polonez driving on our bad roads years ago.

    It will therefore remain to get (or replace) several items.
    The diagram does not differ much from the application from the catalog note CS8190 and is almost the same as the one from Polonez:
    Electronic pointer tachometer for motorcycle

    Assumptions for the project
    1. maximum tip angle is wskazˇwki = 180 degrees
    2. maximum frequency of the input pulse is f = 150 Hz (max revolutions 9000 [rpm] / 60 [sec])
    3. Ccp = 4.7 nF
    4. R3 = 3 k?
    5. R4 = 1 k?

    in the catalog note of the CS8190 integrated circuit the following formula is given for the swing angle of the air-core pointer:
    ? = 970 xfx Ccp x Rt
    so we calculate the value of the resistor Rt from it:
    Rt = ? / (970 xfx Ccp) = 180 / (970 x 150 x 4.7) = 263 k?
    To be able to correct this value, I split it into a series connection of a resistor Rta = 220 k and a potentiometer Rtb = 100 k
    We calculate RC time constants for two cases:
    1.Ccp capacitor charging:
    (R3 + R4) x Ccp = (1 + 3) x4.7 = 18.8 us
    2.Ccp capacitor discharge:
    R3 x Ccp = 3x4.7 = 14.1 us
    and check if the conditions for the minimum input signal period are met, which is:
    Tmin = 1 / fmax = 1/150 Hz = 6.67 ms
    Well, the RC time constants calculated above must be less than 10% Tmin (i.e. 667 us) and this is the case here.

    We then calculate the value of the C4 capacitor, which is a compromise between the acceptable vibration of the pointer,
    and sometimes her reaction to the signal. The catalog note gives the following formula:
    C4 = (Ccp x 6.3 V) / ?Vmax
    In my design, I assumed that the vibration of the hands were relatively small at the expense of the reaction speed.
    I assumed ?Vmax = 30 mV and hence the calculated value:
    C4 = (4.7 x 6.3) / 0.03 = 1 uF

    The experimental value of the C5 capacitor is yet to be selected if the air-core would be without a return spring (they are such)
    My air-core has such a spring, so C5 is completely unnecessary, but I kept it for more reliable filtration of the supply voltage
    (C5 = 100 uF and C6 = 100 nF)

    Summary of items:
    R1, R5 = 1 k?
    R2 = 4.7 k?
    R3 = 10 k?
    R4 = 3 k?
    R6 = 4,7
    Rta = 220 k?
    Rtb = 100 k?
    C1, C2, C6 = 100 nF
    C3 = 4.7 nF
    C4 = 1 uF
    C5 = 100 uF (25 V)
    D1 = np. 1N4001
    D2 = Zener 30-50 V
    Air-core with a coil resistance of about 200 ?

    Three stacked PCBs. The bottom is the main board with all electronic components on board.
    The middle one is the base for the air-core, and the top one has SMD LEDs that illuminate the dial and pointer
    on red. LEDs are powered from a separate light circuit in the motorcycle.
    The power supply to the electronics itself is taken of course "behind the ignition"
    The pulse signal comes directly from the ignition module output to the coil (keyed + 12V)
    A few photos about the installation of the tiles:
    Electronic pointer tachometer for motorcycle Electronic pointer tachometer for motorcycle Electronic pointer tachometer for motorcycle
    Electronic pointer tachometer for motorcycle Electronic pointer tachometer for motorcycle Electronic pointer tachometer for motorcycle

    Launching is reduced to connecting the tachometer input to the ignition module output where the signal goes to the coil
    ignition and potentiometer adjustment of the indicated RPM so that they are as close to real as possible.
    Current consumption about 50mA.
    Vibration tips while driving due to shocks are gone, as I mentioned the air-core drive has a strong return spring and it seems to be an exam.

    Cool! Ranking DIY
    Can you write similar article? Send message to me and you will get SD card 64GB.
    About Author
    Level 17  
    jaclew wrote 188 posts with rating 196, helped 24 times. Live in city Rzeszˇw. Been with us since 2011 year.
  • #2
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  • #3
    Level 16  
    Very nice design and importantly described exactly. If someone wants to transfer it to a multi-cylinder motorcycle, there will be no problem because it is written how to calculate everything. This backlight came out so bad in the picture or does it really look like this? You could try to put a milky foil on the underside of the dial to disperse them a bit.

    R-MIK wrote:
    I didn't deduce from the description that you made the PCB yourself (no description of the version)

    I recommend looking through the photographs and see a colleague that the original indicator plate was not used here.

    R-MIK wrote:
    Maybe it is good for a diploma thesis (at the current level of education it is a doctorate) but for DIY?
    I made a TV set. I actually bought it and took it out of the box myself. Later (very complicated) I replaced the power cable with a straight plug with an angled one. I am very proud, I will write a doctorate on this subject

    A colleague could justify his statement because she is incomprehensible to me. Ie. What is this TV about?
  • #4
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  • #5
    Level 11  
    Tell me exactly what Polonaise these clocks were from? I suspect that not every tachometer was mounted on this CS system.
  • #6
    Level 18  
    R-MIK wrote:
    If the PCB was not made by yourself, then the design should not be in this section. If alone it is only because of the PCB.

    Terrible clinging. The author has carried out work, which he described quite accurately. He made mechanical modifications, took into account the adaptation of the integrated circuit application to work in a specific vehicle (engine). If you think that the presented project is worthless as DIY only because of your doubts about the implementation of the PCB, substantively justify it. Irony with the TV and writing about the exchange of several elements is no justification. The project is not complicated but the information was collected in one place and simplify such modifications to other people. However, it is worth expanding the topic of calibration - it should be done with the help of a generator or other source known and quite low frequency.
  • #7
    Level 28  
    djfarad02 wrote:
    Terrible clinging.

    Give R-MIK a break. This is an outstanding specialist in every field. He did not make such arrangements.
    Read it yourself this subject .

    I like the layout, a good way to use parts from the shuffle that might otherwise have been milling.
    Although old Polish cars - toddlers, big Fiats, not to mention Mermaids or Warsaw - have recently come at a price. Perhaps parts for the Polonaise will be in great demand. In this case, the demolition of functional elements is like destroying exhibits in a museum ;-)
  • #8
    Level 17  
    k9mil wrote:
    someone will want to transfer it to a multi-cylinder motorcycle, there will be no problem because it is written how to calculate everything.

    djfarad02 wrote:
    the information has been gathered in one place and will simplify such alterations to other people

    ... and this is what I described here! Thank you for your accurate remarks k9mil and djfarad02
    Not every writing here must be a diploma thesis right away as not every diploma thesis is suitable for ... reading.
    So much for the subject.

    k9mil wrote:
    This backlight came out so bad in the picture or does it really look like this?

    As for the highlight, the fact came out poorly in the photo, in fact it looks better.
    I'll do it without a flash - somehow smoky, unnatural and out of focus; with a lamp - you can't see the backlight at all.

    vp32 wrote:
    Tell me exactly what Polonaise these clocks were from?

    The clocks when I bought were hand-written on the glass "FSO Polonez 1.6 1998"
    Perhaps other Polonez models also have the same tachometers, but I can't advise you better on this.

    djfarad02 wrote:
    However, it is worth expanding the topic of calibration - it should be done with the help of a generator or other source known and quite low frequency.

    So I develop - I recommend the simplest amateur method: connect a transformer with a 5-10 V output to the tachometer input.
    Adjust the Rtb potentiometer in such a way that these 50 Hz correspond to the calculated rpm value (for me it was 3000 rpm)

    For one malcontent - PCB photos:
    Electronic pointer tachometer for motorcycle Electronic pointer tachometer for motorcycle Electronic pointer tachometer for motorcycle Electronic pointer tachometer for motorcycle

    Greetings to constructive Forumers :)

    Moderated By tmf:

    There is nothing to be discouraged from. The price we pay for freedom of speech are various comments, also unflattering. It's important to do your job.

  • #9
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  • #10
    Level 17  
    Christophorus wrote:
    it could be useful to protect the plate against moisture

    The PCB was protected with PVB60 after testing and final seating in the housing.
    It is quite tight so moisture is unlikely to appear.

    I attach a short video showing how the tachometer works on my motorcycle:

  • #11
    Level 13  
    Is this suitable for diesel? Does anyone know if the signal from the 'W' alternator will be sufficient for the tachometer to operate?

    PS project great, it will definitely be useful :)
  • #12
    Level 17  
    CS8190 is basically an f / U converter and should be adaptable to the "W" output of a diesel alternator.
    The following conditions must be met:
    - the maximum voltage applied to the system input should not exceed its supply voltage
    - the maximum frequency of the processed signal is 20 kHz

    Linearity of the "W" output frequency from the motor speed must be maintained.
    Many say the oscilloscope if possible.
    The calculation principle will remain the same.
    Best regards.
  • #13
    Moderator of Cars
    The CS8190 system is an old age, for differential control, with two coils. In newer motorcycles, the tachometer system is based on TB9226, where the number of cylinders is configured with jumpers. Still another variation was, for example, MS1-1 with e.g. "toddler" on 4 transistors. Once upon a time I was tempted to convert an econometer from a trabant - a diode ruler, probably based on UAA170 on a tachometer for an MZ motorcycle - an unearthly bajer, as the diodes lit up as the revs increased. A generally interesting gadget, an ingenious alternative to the mechanical drive of the indicator.
  • #14
    Level 17  
    Right, CS8190 is old, but it is relatively easy and cheap to obtain from Polonez clocks.
    It controls the logometer, which is also an advantage, because it is a simple drive and fault-tolerant.
    The disadvantage is quite a large power consumption.
    You can use different drivers, but the newer generation probably are typically digital and only work together
    with a special motorcycle ignition module output.
    Developing such communication is more difficult to grasp and adapt to your own expectations.
    And some certainly also control stepper motors - a fact very resistant to shocks, but the situation becomes more complicated when you want to match any particular stepper to a particular driver.
    And with the quotient system there is no problem - practically everyone will come under CS8190.
    This is an important advantage of this analog "antiquity" in the context of "do it yourself"

    As for MS1-1, this is just an archaic and maybe it has soul (because you can change everything in it)
    BUT controls the magnetoelectric indicator. It is a delicate system, probably not found in motorcycles.
    Once I dug it out of clocks from the Mercedes W124 and although made solidly and precisely it is a tip
    in it she wandered on the scale even when tilting or puffing :)

    LED lines do not amuse me in such an application. Maybe toto and effective but also irritating.
    My project met my expectations and I consider it "plus positive" ;)

    (air-core = quotient system = logometer)
  • #15
    Level 28  
    robokop wrote:
    In newer motorcycles, the tachometer system is based on TB9226, where the number of cylinders is configured with jumpers.

    Do you have datascheet for TB9226 ??
  • #16
    Level 1  
    Is it possible to obtain a PCB schematic on a 1: 1 scale, I have a tachometer in xt 600
  • #17
    Level 25  
    I used to do several tachometers, the one from the polonaise has a very high pointer inertia. In my opinion, the best ones are AutoGauge. They have regulations for 2, 4, 6 cylinders,
    and the conversion consists in replacing 1 resistor.