av8or1

Hi Y'all-

Hope all is well. I am creating a new thread tonight to announce that my endeavor to build a new rotary engine compression tester is in its final stages. I am calling my version/incantation/variant by the name of JDACT RaPiD, thus the title of the thread. I'd like to give a quick background of how I got here, then move on to where things currently find themselves and finally conclude with the particulars of how I hope this journey will end up. I'll try to keep it brief, but I 'fess up front that I have the gift of gab (or some deviation thereof), so...

HOW I GOT HERE

The short version is that a few years ago I bought a TR01 compression tester from John in Houston, perhaps many of you are familiar with it. I was using it to perform a compression test on a friend's car. I let him connect the unit to the rear rotor while I went back inside the workshop for ... something, don't remember now. Well he broke the tester when he attempted to get it configured. He didn't do it on purpose of course, but in the end it was broken nonetheless. But the TR01 wasn't being produced or supported (which I can understand actually), and so I had little choice but to repair it myself or go back to the old school way (conventional piston pressure gauge tester) of doing things. I don't mind using a conventional tester, but having and using a rotary-specific one is "just way better". So I wanted to keep that option available by owning one and having it in my toolbox, ready-to-go whenever I needed it. And I was glad to help other local rotary types by allowing them to use/borrow it, but at the same time I didn't want to go down this it's-broken road again. Therefore I decided not to repair my TR01 and since I wasn't going to settle for the conventional tester thing I decided to just develop one of my own. And that was the launching point of this oddysey - it was born of necessity. More virtual in this case, but I digress.


It seems worthy to note that I didn't begin this side project with the intention of making a profit from any sales that might follow. Such a notion seems kinda silly and self-serving to me, for whatever reason. No, for me, I wanted to work on this so that I could develop a device that I would want to have in my own toolbox. And if anything came after that, so be it, but whichever. I also wanted learn lotsa new stuff (which have I ever - whoa!) about microcontrollers, electronics design, etc. I am a software guy by day, so I don't have an opportunity to be involved in that type of technical arena, but I have been curious about it. Finally, I wanted to help others in the rotary community and give my buddies an alternative to breaking my unit. lol

WHERE I AM NOW

After several design changes (and accompanying "mind changes" - lol), seemingly-endless component R&D and an extended 3-month battle with an unexpected - but quite serious - health issue, I have finally completed the first prototype. Well, that is except for the enclosure, I couldn't find a commercial-off-the-shelf offering that looked "professional enough" and that would cleanly house the components that comprise the device. So I am working with an enclosure guy to develop a custom box. And that is the primary reason that I don't have any static pictures of the device at this point. No enclosure. I'll post pictures and perhaps a video as soon as I have something presentable to offer.

HOW I HOPE TO FINISH

First and foremost is that I am happy with the initial testing. More is to follow of course, but I'd like to have a production version ready by the end of the year. Obstacles remain, the biggest of which is a requirement that I have maintained since the outset and that is to develop a device for as low of a cost as I can. I'm trying to stay under the beverage-beer-spending-budget-so-I-don't-need-to-tell-the-other-half line in the sand. While producing an accurate instrumentation tool. And a tool that is reliable. And good quality. And that uses good materials and components. And that looks at least halfway "professional." And that meets the additional requirements that I decided to pursue. And that is something I want in my own toolbox. A monolithic challenge it has been, no doubt. Cost has made several design decisions for me, but that's been part of the fun really: working through the engineering, design and project management challenges that such an endeavor presents. Anyway, we'll see.

So there it is, my announcement. JDACT RaPiD. FYI, after coming through the health thing, I'm more determined to finish than I was in March or April or whenever it was that I started down this road. I can actually see the light at the end of the tunnel WRT this project, and being able to see that light is a wonderful thing! I haven't touched my cars in a while now and would like to get back to that instead of working on this "side project". Soon. Hopefully soon.

I may post more detailed information in a few minutes, for those who might be curious. Thank you for reading!

Best,

Jerry

ps-I am an RX7 guy, so I hang out in that forum more so than this one; that said, I hope I can be considered a "brother" and welcomed nonetheless!

av8or1

It's raining outside, so I cannot go for my nightly run at the moment.

Here's a few of the technical notes that I made back in April or so regarding the development of a new tester. This is more of a "features list" if you will rather than a design or a schematic:

• R/C components for hardware ADC signal smoothing
• Momemtary pushbutton for ON/OFF
• Automatic device shutdown after X amount of time of inactivity
• 1000 Hz sample rate minimum
• Threaded data acquistion and data store functionality separation
• Different modes to support different device capabilities
• Keypad for user input, primary consisting of mode selection
• POT controls for both LCD contrast and backlight
• Low battery warning
• FRAM data storage, primarily for device options and data analysis
• External data storage mechanism for data logging (ended up being an SD card)
• Altitude (if using PSIS transducer), dead volume and normalization corrections
• Presentation of compression readings in different units (PSI, BAR, etc.)
• PIN access
• Rudimentary diagnostic information - GUIDANCE only
• Simultaneous processing of 1 - 4 compression units (CUs)

This list is rather old, so I may need to update it later. lol

Thanks!

wcs

iTrader: (2)

Nice
sub'd

RX8Soldier

iTrader: (24)

Also sub'd.

Carbon8

iTrader: (4)

Is this because the other vendors stopped selling them? Just not sure why you would go threw all the trouble when their are offered products available to achieve this relatively priced.

Either way wanting to pic one up before January so sub'd

alnielsen

iTrader: (4)

Jerry, of course you are welcome here.

Anyone wanting that compression tester, I believe they are going to be re-introduced at SevenStock.

TR-01 Rotary Engine Compression Tester

av8or1

Yeah, it was mostly because the one I had was not being supported or produced. However, there were also features that I would have liked to see in a compression tester that didn't exist in the one I had. Finally, I wanted to learn more about electronics design, PCB manufacturing and s/w integration with the result of that process. I wrote the software in short order, since it's what I do everyday. It's been the hardware aspect of the project that has afforded me the greatest opportunity to learn. And that's a good thing.

Thanks

av8or1

Alnielsen,

Thank you for the welcome. I was not aware that John was back at it. Last I heard it was still on hold. If he does reintroduce them, then my project may not be needed so much. That said, I will complete it regardless. Even if I just make one and keep it myself, that'll work for me.

Anyway, we'll see. Thanks for the heads up. Personally I wish John and the Rotary Diagnostics guy all the best!

Jerry

av8or1

Y'all-

My response to a post made on the RX7club forum. Just FYI. Thanks

Thanks. Yeah we have a Fry's in Austin. I looked into their enclosures when I began working on the project but didn't really see anything that would work. Enclosures has ended up being a much tougher nut to crack than I ever anticipated, which has been a good learning opportunity. Standoffs were one of the primary concerns with the off-the-shelf units, amongst other things. Any one and most certainly all of those concerns in summation would yield a rather considerable time sink during production.

Thus I decided to just go custom. With that approach I receive my enclosures in the mail, remove the back cover, screw the PCB into place, close the back cover, secure it into place and done. In addition you can incorporate silkscreening on your custom box, so that comes direct-from-the-manufacturer too, which is even more convenient.

Although I don't have any static pictures yet due to the enclosure issue (and that is the reason I've delayed posting until now) I do have some early drawings to offer. They should give you a rough idea of what it will look like. The end design will most closely resemble the split-diagram picture, but the internal design has changed from when I drew that. I consolidated the different PCBs into one, save for the LCD PCB. But I digress. I chose a portait layout instead of landscape and I decided to include a hook for under-hood hanging of the device for convenience.

Anyway. Thanks again.

Jerry

REtali8

iTrader: (2)

Since your in Austin, have you considered making them at TechShop in Round Rock? They would have all the equipment you would need.

Mercatis

sub'd

av8or1

Oh sure, as soon as I learned that there was/is a TechShop in Austin I went for the full tour with a couple of buddies from the local rotary club. Great place, but I didn't really see much there that could help me with this project. I felt that the 3D printers wouldn't produce a good quality enclosure, so I decided to forego travelling down that path. I did like their powder coating facility however. Good for small-ish stuff like suspension components and such. So I'm likely to try that out someday. Gotta finish this electronics project before getting back to the cars though!

Thanks

REtali8

iTrader: (2)

I wouldn't use a 3D printer for this either. Depending on skill set and how much time you wanted to spend on enclosure, lot can be done between 4 axis CNC machine, flow-jet cutting table, full metal forming shop, vacuum forming, and available welders.

av8or1

I agree, lots could be had with a CNC, flow jet cutter, welder, etc. However, as with several spects of this project, cost and most importantly ease of production were paramount in my approach from the very beginning. I spent hours and hours and hours doing the R&D for this project; didn't wanna do the same during production. Wanted to avoid time sinks wherever possible during that phase of the process, so a I'll-just-make-my-own approach to the notion of an enclosure went South rather quickly. For me it was going to be an easily-adaptable off-the-shelf unit or a custom box. I ended up going with the latter after a few *exhaustive* Google searches failed to produce a viable off-the-shelf option.

Thanks

YuppY

Interesting project. What is purpose of device keyboard? If one of your goals is low cost of device then text file on SD card to set different correction options would be a better choice.

And, by the way, another variant of compression tester is laptop-connected Arduino with pressure sensor: Ðîòîðíûé êîìïðåññîìåòð ñâîèìè ðóêàìè - In Rotor We Trust. Ôîðóì Mazda RX-7 è Mazda RX-8 â Ðîññèè. (sorry for description in russian)
It doesn't even try to look professional, but total price is less than $100.

av8or1

Privet YuppY-

The purpose of the keypad is to control the device, set and/or change options, enter data and page through the various "screens" that will be presented. Good work regarding the DIY tester! I opted to go for the "more professional" looking solution, which does involve a slightly higher cost, but avoids the need to download sketches, hook stuff up to a laptop, etc. It's an all-in-one type of approach: a hand held device that you can store in your toolbox and drag out whenever you want. Set it up with a minimum of fuss, get your data and then put it away until next time. The custom enclosure will be 4mm black ABS plastic, so it should be reasonably rugged/sturdy, and with custom silkscreening. Portrait layout, as I mentioned already, so the idea is that you can hold the entire device in your hand (eg no laptop, no wires running around, etc.) and see the pressures as they are displayed in realtime on the LCD. Or hang it under the hood to be hands-free. Finally, I do store the user-configurable options between usages, but on FRAM rather than an SD card. Thus the SD card is optional. If you wanna store your data on the SD card, my device will do that and not miss any pressure readings due to the threaded approach with which I have separated data acquisition from data logging. Then you can take your SD card out of the device, leave the device in the toolbox, walk inside the house and sit in your favorite comfy chair (or laptop it in the garage if you want, whatever) and plot the data however you want (Excel, etc.) 'til your heart's content. But anyway. I'll stop there.

BTW, I am a fan of the Volga! I have travelled to Moscow in the past, and have several Volga buddies there. FYI only.

Thanks (Spacibo)

av8or1

Y'all-

Just as an FYI, I got the new rev 1.1 board back from the assembly house yesterday and began unit testing. Looks good so far. Keypad verifies, as does FRAM, serial I/O, serial programming, ICSP programming and PB on/off via the power controller. Other things left to test, but that's a good start. I've begun work in earnest with the custom enclosure guy, so with any luck I can make the end-of-the-year goal. We'll see.

Anyway, thanks

YuppY

Great, spasibo

BTW, one of russian RX-8 club members have built this GAZ 24 with rotary engine: Волга Ñ� роторно-поршневым двигателем - 20 ОктÑ�брÑ� 2009 - Блог - Ð*то интереÑ�но...

IronHulk

Subscribed.

detectiveorange

This is so amazing man! Sub'd. It's so awesome that a lot of people would say "why would you build one when you can just buy one?" and you seem to have a "because screw it, I'll do it myself. AND I'll learn something in the process" kind of answer/attitude. Inspiring stuff man! Keep at it!

av8or1

Thanks! Yeah this project was born out of a virtual necessity and a curiosity to learn. In addition, one of the larger reasons I began work on my own version of a compression tester was because there were additional features that I wanted in a tester that I didn't see in any other testers. I understood that, those testers were built with different goals and a different implementation strategy. All of them that I have seen are completely viable and acceptable solutions considering those aforementioned goals and strategies with which they were designed and built. I just wanted a little more functionality, that's all. It was and is a type of "that's cool, but wouldn't it be even cooler if we made it do this?" scenario. I did a lot of that in the beginning when I was completing the initial feature list. I have simply put off listing or discussing those additional "cool" features that I will have in my tester due to the avalanche of criticism that I anticipate experiencing once I put it all out there. Eventually it'll have to come out of course, but I'll continue to hold off. For now.

And having said that, I would be interested to hear a little more detailed information from the RX8 types who have experience with those engines. I suspect that the results will be similar to my RX7s, but I'd like to ask anyway. If you had to "grade" your engine's compression test results, what kind of scale would you use?

Thanks again

ps-Found an issue in the rev 1.1 design with the LCD shift register; have corrected that and ordered new boards. All other components passed unit testing. Continuing on with the final development testing, just sending everything to serial out for the time being. The custom enclosure guy is at-work on the prototype, says it should be ready in two or three weeks. So the end of the year goal might still happen, but it's gonna be tight. We'll see.

av8or1

QUICK UPDATE

Hi - hope everyone's holiday was good. Thought I'd give a quick report. I received the new boards late last week, they look good. Turned a couple over to the assembly guy today at lunch. It'll be ready on Monday. These new boards have the corrected shift registers, new tracing, reversed power controller output logic and a different set of LEDs for the system status stuff.

That said I have continued working on the final development of one of the aspects of the device that drew my attention way-o-way back in the beginning. That's been kinda fun to work on and I would welcome feedback from other rotary types/end users; but I suppose that is a little further down the road.

Finally, I received the new transducer that I will likely utilize as the base-model variant. It's a rugged, heavy-duty industrial transducer made of 316SS. The only thing I don't like about it is that it's a sealed gauge transducer (PSIS) and so the altitude variation will have to be compensated for in software. wcs posted that chart some time ago, unknown reference, but from my research on the matter it's accurate. I would have preferred to utilize a gauge transducer (PSIG) so that the pressure altitude is compensated for automatically (no need for the software to do anything), but I just couldn't find a gauge transducer that met my quality standards for a price that would allow the ultimate end product to be attractive to its intended audience. That said, I do plan to offer a gauge transducer option, though for a slightly higher cost. Ergo, let the end user make that decision. The reality is that the difference between the two options will be quite small, if existent, once the altitude deviation is accounted for in software. I plan to put some hard numbers to that assertion, probably over the weekend. We'll see.

So that's where things are. Unfortunately the custom enclosure guy is flaking on me at present. Dunno if he's just swamped or what, but I am investigating other custom enclosure options as I write this post.

Thanks,

Jerry

REtali8

iTrader: (2)

Thanks for the update. When you get some finished and price point figured out, let me know. Will pop down and get one from you.

av8or1

REtali8-

Ok thank you for the interest and support. 'Preciate it.

I am picking up the newest board from the assembler guy today. Kinda exciting because barring any unforseen and substantial issue that I encounter during the upcoming testing, I think this will be the final design for version 1.1.

I've been excited to work on this stuff for the past few days because I am finally getting to one aspect of the project that interested me the most from the outset: the diagnostic/heuristic stuff. Yeah, that's right, you heard me. One feature of my tester is that it will provide diagnostic information, to be used as guidance ONLY and such information will ONLY be displayed if you ask to see that information (by pressing the DIAG button), based on the data collected during a given run.

The aforementioned data from a given run is first corrected for dead volume and altitude variance. It is then normalized. So no more need to go to other websites or apps to correct your data. I didn't understand one aspect of that anyway, but I digress. Finally, conclusions are then drawn regarding the max/min peaks observed, the difference between those peaks (chamber-to-chamber variance), seal integrity and finally rotor-to-rotor variance, should multiple sensors be used simultaneously or if you elect to save-off the data from one run for comparison against a subsequent run; ergo you are only using one transducer. Again, this information is only available if you request it via a button press, so don't sweat the issue of extraneous information being unwillingly piped down your throat. Because it isn't and won't be.

The RX8 stuff is actually easier because the chart offers a minimum and a standard. Therfore developing a grading scheme off of that is easier than my RX7 stuff, which only offers a minimum on its chart. Fortunately I have a fair amount of experience with the RX7 engines, so I have a roughly-good idea of what should be considered an 'A' engine versus 'B' and on down the line. I am open to feedback from all rotary owners who've messed with that stuff in the past however, so if you have something you'd like to offer, please speak up. I will offer free software updates for the life of the product (you'd have to send me your unit to get the upgrade, but might offer a way to upgrade the software on your own if you are tech-savvy and brave enough to try it - lol) but this is the time to get your feedback included in the initial version. :-)

So there it is. One of the aspects/features of my device that I didn't see in others and that I wanted to include from the outset. And that is only one of the features that I have been holding back mention of to-date. Now that one cat is out of the bag, let 'er loose...I'm expecting the beginning of the avalanche of criticism, but that's ok, bring it on. lol :-)

And the new enclosure folk seem promising, but we'll see. Keeping fingers crossed on that one. Who could have predicted that would be such a pain in the tail? lol

Anyway, thanks again.

elysium19

iTrader: (1)

This is awesome, good luck with the project.