Homemade RC Dyno Prototype Testing

[sheilstar12]

what coil awg do u hav to use to attach the headphone ?

[KreyNeeUhm]

Nice work man! Keep it up!

[DamoRC1]

@KreyNeeUhm Thanks!

[MrChevyman1996]

Can you messege me saying a couple of things needed to this? to actually make it work in your computer? would realli apreciate it man! Thanks!!

[DamoRC1]

@MrChevyman1996 Have you tried going to the forum site listed in the "more info". There is a lot of helpful information there. Software is simply a matter of checking that your computer is runing the current .NET framework (4) (there is a tool on the website that tells you what version you have=. Then just download the version 5 ZIP file and run. If you are having problems at this stage, just post a question to the forum and I will do the best I can to help you get it working.

DamoRC

[MrChevyman1996]

@DamoRC1 Thaank You very much!

Ill see how it goes and if anything ill message you with questions! Thanks!

[rccarmods]

what is the output voltage of the battery,that is how many volts

[DamoRC1]

@rccarmods It's a 2S3P pack of Li-ion cells 7.4V and about 1500 mAh

[rccarmods]

and is that a homemade rc car and how did you made it

[DamoRC1]

@rccarmods Nope - t is a heavily modifed Radline 1:24, Masters Series

[rccarmods]

awesom

[DamoRC1]

@rccarmods

Thanks - you should visit the forum and see the SimpleDyno hall of fame - the software has come a long way and folks have built some really nice dynos.

[rccarmods]

is that a homemade battery pack

[DamoRC1]

@rccarmods

Yep - just some radioshack 2 cell holders glued together

[21crazz]

Nice bro that's really nice

[one8apc1]

Hahaha! Sick.

[VCR3AK]

hi. what is this program????

[DamoRC1]

@VCR3AK

It is the original version of "SimpleDyno". You can download the latest version at the website listed in "more info".

[scbjgs]

i'm trying to build one of these for my nitro t maxx, rustler, and ofna 9.5.

i'm not sure how you connect the headphones w/ the coil though. could you please make a vidoe on this?

thanks

[DamoRC1]

@scbjgs

I will try to describe. Starting with an intact set of headphones and your coil (which should have two ends to connect):

(1) Cut off one earpiece and discard (leaving you with a cut wire)

(2) Remove about an inch of the outer covering from the end of the cut wire

(3) You should see two smaller wires (very thin) inside.

(4) Connect one of the thin wires to one end of your coil and the other thin wire wire to the other end of your coil - the polarity does not matter.

[scbjgs]

@DamoRC1 thanks a lot. that did actually make sense.

haha

[berndiggydiggy]

Thanks for not having music. I love the sound of electrons doing work. Fuck yea

[balak121]

do you think instead of using a magnet and coil i could use and electric motor for a sensor.

[DamoRC1]

@balak121 I assume you mean connect a motor to the shaft of one of the rollers so that the motor generates voltage / current pulses when the roller is turning? You could do this provided that the motor provided clean pulses of power that the software could count. I would be wary of connecting this to the mic line on your computer though without some protective circuitry as the voltage / current coming out of the motor might be quite high.

[balak121]

@DamoRC1 yeah what about using a 3 volt motor is that too high.

[DamoRC1]

@balak121

I don't really know for sure. You could try it out a low revs and see if it works. I would consider putting a resistor in between the motor and mic line to be safe.

[balak121]

@DamoRC1 yeah, ive thought about putting a volt meter that i have on the line with the resistor

[DamoRC1]

@balak121

I just tried connecting a small 130 size brushed motor to the mic line and turned it by hand. The signal was impossibly noisy - even with the mic level almost at zero. I put a 15K resistor in series and, although it helped, the signal noise was still too much for the software to handle. Also, as the motor spins faster, the signal voltage increases a lot so it will be difficult to set your signal thresholds on the software. You might still get it to work though.

[balak121]

@DamoRC1 thanks for expeirementing with it ill just use the coil and magnet, how did you make the coil. rap in around a dowel and duck tape it down.

[DamoRC1]

@balak121

I found the coil I use already wound in my junkbox. 6 layers of 40 - 50 turns of magnet wire which is a little thinner than the 30 AWG. You don't need this much of a coil though. I have to turn the mic line input to my laptop down to about 5 or 10% to keep the signal on scale. The coil should be formed around a ferrous core (a nail or bolt would do). I have some descriptions and pics at the website (see more info) although the pics do not always load properly.

[DamoRC1]

@bbfreak11

If you go to the "The Dyno" page on the SimpleDyno website (link in the "More info" section) you will see additional information on how to build the dyno and a link to a MSUK forum thread where two Dyno builds are presented in quite a bit of detail.

If you have a specific question, you can post it at the SimpleDyno forum (link in the 'More info" section).

[jgilk1]

a few bugs i seen it spike @ 0.174hp (128w) im sure it could do a whole hell of a lot better then that.... faulty setup is 95% to blame

[DamoRC1]

@jgilk1

Earlier than the 128W point it actually peaked at 254W! (which is totally unreasonable for this combination of motor and batteries).

The same dyno with the newest software consistently gives about 45 watts peak using the curve fit data. So the software was mostly to blame - not the dyno setup

[jgilk1]

@DamoRC1 take that setup and a laptop down to the track and see what you can get out of a racer nitro.... i just think those # are a little bit low

[DamoRC1]

@jgilk1

I think if I put a nitro racer on this particular dyno - it would shred it!

Remember, this is a 380 sized brushed motor running at 7.4 V (nominal) with a reasonably low gear ratio so 40 - 50 watts mechanical output is about right.

[quadhondarider]

Okay, well I still think its pretty cool, I think the thing will do 35 at most?

[DamoRC1]

@quadhondarider

Thanks, Data collected using the newer software indicate that it will do 28 - 30. I have some Lipo coming for it and I am going to compare what the Dyno says versus what it will actually do on the street. I used to do the street tests with video capture (see my other vids) but this is a lot harder to do accurately at these speeds. I think I can use the same basic dyno signal / software set up to build an optical speed trap. If it works I'll post a vid.

[quadhondarider]

I could've sworn it hit 45 mph.

[DamoRC1]

@quadhondarider

I wish. This was an early version of the software and, combined with a rough dyno build, it was not very accurate. New software is a lot better.

[GompyAkm]

I missing the K-factor into the program. K-factor wheel loaded at rim like a bicycle tire - k =1 flat solid disk of uniform thickness - k = 0.606 flat disk with center hole - k = ~0.3 solid sphere - k = 2/5 thin rim - k = 0.5 radial rod - k = 1/3 circular brush - k = 1/3 thin-walled hollow sphere - k = 2/3 thin rectangular rod - k = 1/2 Try with line in and stereo mic, but I have problems with the unused channel....lot of nois on the channel I not use..

[DamoRC1]

@GompyAkm

What K-factor are your referring to?

[GompyAkm]

@DamoRC1

The K-factor is the shape vorm of the flywheel.

A tube (solid or hollow) or a wheel (small or thin) they have all there own K-factor.

Into a hollow tube all the energie is in the outside of the tube.

Into a sollid *tube* the energie is in the hole *tube*.

Same with a flywheel like a bike wheel, there is all the energie in the outside not in the rods between the axis and the *tube*.

[GompyAkm]

@GompyAkm

tinyurl(dot)com/2vrslrz

[DamoRC1]

@GompyAkm

Sorry - I must have missed this post (it was flagged as spam). So If I understand you correctly, you also want to calculate the kinetic energy stored in the roller (in your case the wheel)?

[GompyAkm]

@DamoRC1

If you don't use the K-factor, the values are not correct.

In your program, you calculate only the weight of the flywheel.

I can do this also with a balance, but then I mis the manner of to behave from the flywheel / roller.

[DamoRC1]

@GompyAkm

I will read the reference a little more carefully but to clarify, the software does not simply consider the weight of the flywheel. It uses the geometry and the mass to calculate the correct moment of inertia for the various components. For example it uses different calculations for the "roller" / cylindrical portion of the dyno than for the endcaps (which are solid disks).

[GompyAkm]

@DamoRC1

OK, but if I calculate with the same values as I use into your program, I get differend end values.

It isn't much, I can wrok with it and your software is allways better then calculate by hand......it takes to much time :o)

[DamoRC1]

@GompyAkm

Thanks. There is a always a possibility that there is an error in the software that I have not detected. So if you could post your numbers I can double check.

[GompyAkm]

@DamoRC1

You can download the exelsheet if you wish.

test(dot)gompy(dot)net(slesh)i­nertia.xls

[DamoRC1]

@GompyAkm

Sounds like it is related to the moment of inertia of the dyno components. The software takes this into consideration when you enter the parameters for the rollers, end caps and axles. So I am unsure what you are asking for - do you want to be able to enter a K factor for your flywheel? You should be able to do this with the currently available inputs.

[GompyAkm]

I get a error after install version 3.

myWaveHandler_Processwave / waveInPrepareHeader Error

CU, Rob

[GompyAkm]

@GompyAkm

I'm using window XP on a Dell laptop

[GompyAkm]

@GompyAkm

I'm missing the pulses per rotation input.

With one magnet into the roller you get vibrations

[DamoRC1]

@GompyAkm

Re Error -> Does this happen every time? Can you get the software to run eventually?

Re Missing Pulses -> You may have to increase the "volume" for the mic input line.

Re One Magnet and Vibrations -> Yes, at high RPM this will happen. You can use a second balancing magnet, diametrically opposed to the first, and set the "Signals Per RPM" setting to 2 (default is 1).

[GompyAkm]

@DamoRC1

Only the first time I start the program, the escond time no problems.

I use this to detect the pulses, one with a opto and the other with a pickupcoil.

electronics.gompy.net/sensor01­.jpg

[DamoRC1]

@GompyAkm

Thanks for additional info. This has not been tested with a USB powered detection circuit such as the ones in the link, only a "passive" coil / magnet system, so I cannot comment as to whether it will work with your circuits.

Have you tried just a basic coil pickup ?

[GompyAkm]

@DamoRC1

I try a pickupcoil for the telephone from HobbyShack, but I get to much *nois*, there are no real spikes the program can trigger on.

I think this will be a problem if you don't have the right coil.

With the CD4093 I get a real digital puls on the output.

It doesn't matter how you wind the coil, it allways work.

If you wind a coil around a nail and let spin the magnet near the head of the nail it will funtion.

.

BTW, a small nail is given a small spike.

[DamoRC1]

@GompyAkm

Does this mean it is working for you now?

[GompyAkm]

@DamoRC1

Yes, without any problems......but my dyno is a littlebit bigger ;o)

area51.gompy.net/dyno/P1010502­.JPG

[GompyAkm]

@GompyAkm

BTW, the program need to start twice, the second time the error is gone.

[DamoRC1]

@GompyAkm

Yep - that is some Dyno! Cool project by the way.

[GompyAkm]

@DamoRC1

Can you rewrite the program to use the line input and not the microphone ?

The micro can handle only one channel becourse it's mono.

With line-in you can use two channels, left and right.

Left channel for the dyno and right for......engine temperature ?

With a PTC or NTC and a AD-convertor you can translate the analog signal to a digital pulssignal.

[DamoRC1]

@GompyAkm

If you select "line-in" as your input device and connect the dyno to your line-in jack does it work for you? My laptop does not have a separate line-in jack, so I cannot test this although Windows allows me to select line-in as the recording device (which does not work obviously).

[DamoRC1]

@GompyAkm

Had a quick look at the software tonight and enabled stereo audio capture and it works fine through the mic line. Using the stereo headphones that I hacked, one channel connected to the dyno coil and the other channel connected to a photocell which was pointing at my fluorescent tube lights, I was able to pick up two distinct channels of data. There was some interference on the dyno line from the photocell signal due to the size of the signal. 

[GompyAkm]

@DamoRC1

As far as I know there are no computer with a stereo microphone input.

The microphone input is allway on both channels the same.

Only the line input is stereo, zeitnitz.de/Christian/scope_en

[DamoRC1]

@GompyAkm

I'll need to look into this some more because I am pretty sure that I was able to pick up two separate data streams through the mic line on my laptop. I'll try again tonight using that really nice scope software.

Did you try to run the software with the dyno connected to your line in (and line in selected through windows as your default recording "device"). The SimpleDyno software records through whatever the default Windows device has been selected.

[GompyAkm]

@DamoRC1

I didn't try within the window GUI to change the recording default.

In to the most programs you have to change it into the program it self.

Wat will happen if I ad both options, line in and microphone ?

You can use line-in for your MP3player and the microphone to communicate with MSN.

I think you have to set the program to listen to one port, line-in or phone.

This weekend I'll test the software on the dyno, now I test it with a pulsgenerator.

[GompyAkm]

BTW, I've still start the program twice.

The first time I get the error, the second time there is no problem anymore.

[DamoRC1]

@GompyAkm

I am not sure what happens if you activate both the line in and mic. You may have to test that with your pulse generator. Ultimately, I could add the code required to allow you to select a specific device to "listen" to but it's not high on the list of things to do right now.

[GompyAkm]

@DamoRC1

Have yoy ever try this to receive the data, USB to TTL ?

cgi.ebay.nl/USB-2-0-to-TTL-UAR­T-6PIN-Module-Serial-Converter­-CP2102-/170484687886?cmd=View­Item&pt=AU_Components&hash=ite­m27b1ade40e

[GompyAkm]

@DamoRC1

I can't find a line-in into your program.

[LunaticoYaControla1]

Can You Please PM Me ABout How To Do This & What Do I Need Exactly To Get It To Work Like This.

[DamoRC1]

@LunaticoYaControla1

If you go to the simpledyno website listed in "More Info" there are some additional details there, plus links to other folks who have built one. If you have a specific question please feel free to ask.

[DamoRC1]

@member

First off, sorry about the software. On Vista and Win7 it has mutiple issues that I am trying to figure out.

Without knowing exactly what your setup is and what you are trying to measure, it's difficult to say whether it is appropriate for your needs. Have you posted your work online? Something that gives me a better idea of what you are working on?

[member8761]

Hi Damo,

I am developing a wave energy device. I need to take power and rpm readings from a scaled model in my wave tank. I have downloaded your software but it crashes quite a bit (windows 7). The main problem I have though is that my device is low rpm say 12, but high torque. Do you think that this can be accommodated by your software? Aside from all of that, well done on producing something really usefull, I had readings for about £20 and the coil took 30 mins to build.

[DamoRC1]

Just a quick update. A very "beta" version of the new software is available at the website. Feel free to try it out and let me know what you think.  It has some problems on Vista and Win 7 systems that I am looking into.

[DamoRC1]

No probs - keep an eye on the website - a new version of the software will be available soon.

[rcbackyardtrack]

Thank you very much for setting up a website and sharing your software and instructions!

[liteglow2000]

Thanx for the software, and for the setup !

2 question.

is it possible to get the MPH = KPH ? :)

Second question, I did not understand the coil you did make..

Just a coil of wires, and a magnet on the spinning wheel??

Can I use a Bike-Cycle speedometer magnet sensor ? :)

Cheers again

[DamoRC1]

@liteglow2000

MPH to KPH = MPH x 1.6 ;). I will try to remember to include in next version

The bike speedometer should work fine if you can connect it to the PC through the mic jack as I assume it works on the same principal. The coil is just a coil of magnet wire which you can easily buy or hack from an old transformer or even and old motor. I have posted some pics of the coil and a link to another dyno build where he wound his own coil.

Good luck

[WKDM1ND]

Thanks for the Pic that really helps. I have been "Scrap Heap Challange" round the office and scored a few coils from various old equipment will test it tonight and let you know how i get on. Once i have it all working ill post a video reply.

Once again a sincere thanks for sharing this, I am sure theres more than me that will get a lot of use out of it.

[DamoRC1]

@WKDM1ND

Your welcome. I hope it works out for you and I am looking forward to seeing how you do

[WKDM1ND]

A pic of that coil would be great i have successfully built a rolling road and tried to make the circuit from a set of headphones (I used the coil from the headphone) i suspect this isnt strong enough as i can not get it to register,

However im using a mac book with bootcamp and im not sure if the problems with the line in port under windows or the circuit. If i use audio hijack in Mac OSX on the line in port it does show a fluctuating signal on the line in when i spin the roller.

[DamoRC1]

@WKDM1ND

I have just posted a pic of the coil at the website ("The Dyno" page). This coil is overkill, but your headphone coil is probably not going to do the job either. Also, if I understand this correctly, you will get a better signal if the coil is formed around a ferrous core.

I can't tell you if the software will work properly on a Mac running Bootcamp (I am surprised it even runs!). \

I would start by making a better coil. Hope this helps and thanks for watching.

[dash25uk]

Nice job. think might make one for my rc nitro cars.

Looks easy enoght (famous last words) does the size of the coil matter? any chance you taking pic of the coil? and did you have to chop the other headphone of the cable?

Again nice work

[DamoRC1]

@dash25uk

I will try to post a pic of the coil on the website. But is does not have to be a huge coil - probably 20 turns (2 layers of 10 turns) around a 3 - 5 mm ferrous core should do (I have to turn the line input level on my "mic" way down to get on scale readings.

You don't have to cut off the other headphone, unless you want the second magnet (my current version has two magnets diametrically opposed on the roller)

[nitrocrawler95]

what all went into writing the software. is it hard for a person who hasnt written software be4. is there any free software that would work with the coil stuff that i could just download and last, where is that plug plugged into on the laptop?

[DamoRC1]

I posted a link to the software in the "more info" section. It's rough and has problems with vista but it kinda works. Let me know if you can run it.

The coil is connected via a standard headphone jack into the microphone jack on your computer.

[nitrocrawler95]

is the duct tape a coil with a magnet on the roller and by custom software do u mean its homemade?

[DamoRC1]

Yes - the coil is held onto the frame with duct tape and the small magnet is mounted on the roller.

Yes - I wrote the software

[ND0994]

Could you please tell me how and what materials you used to make this Dyno, l would love to know, thanx

[DamoRC1]

The rollers and ends are just plastic drain pipe pieces from the local Homedepot hardware store. The roller axles are 5 mm bolts which just happen to fit some spare bearings that I had from the car. I can't remember where I got the coil from (has been sitting in my junkbox for ever) but you could make one with a nail and some magnet wire. The magnet is from a set of headphones. I'll be posting the dyno build somewhere so when I do I will update with a link.

[rcgalor]

is it accurate?

[DamoRC1]

I think that it is reasonably accurate but that is one of the things I am working on, mostly on the software side. The only thing it really measures is the RPM. All the other values are calculated based on this. Note that the MPH reported is only accurate for the car sitting on the dyno. On the road it would run quite a bit slower (which is true for all dyno speed tests)

[krypticmac]

ok that is awesome.

[DamoRC1]

Thanks Krypticmac!