Machtac

royesses

In Memory
Rest In Peace
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Aug 23, 2014
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Henry Arnold has released to the world the Machtach schematics, source code and other information at:

It includes the hex file and C source code for the PIC16F690-IP microprocessor. All files are available for free download.
There is a download link at the top right of the page. The zip file is too large to attach here.
Got to give him a well deserved thank you for releasing it to everyone. He is a great guy and brilliant engineer.

Roy
 
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WOW - Talk about timing!!! I just unearthed a vintage MachTach kit and assembled it last week! Used to subscribe to his Yahoo group, but they've all been shut down. Tried an internet search, but no joy. Anyway, got it built and enclosed, and it works well. I'll have to try sending him kudos through thingvrese. THANKS for the link!
 
I burned an extra PIC16F690 yesterday as a spare just in case my machtachs get damaged. I haven't tried it yet to see if it burned ok although the burner said it passed. The copy protect bit is turned on in his code so a subsequent verify will come back with all zero's even thought the pic is properly programmed. All the other parts are easily sourced from Digikey except the printed circuit board. He is a great guy to talk to, very knowledgeable. He is a retired electrical engineer.

Roy
 
Also spoke to him after he closed down making the MachTach, in my opinion one of the best tach/SFM units at the price level, but just too much competition from the Asian sellers to continuing making them. I have also used the Tachulator in subsequent builds, but the MachTach is more versatile to different machines. The Tachulator only comes with an optical reader although I have converted them over to magnetic sensors. Asked him to burn a batch of MachTach control chips for me since I do not have a PIC programmer. If someone wants to go in on a run of the circuit boards, I would be interested in 5-10 boards. The price goes down the larger the batch.
 
One of my MachTachs had the voltage regulator fail recently. (Bolt the reg, U2, to the board or machine vibration could cause the legs on the reg to break.) I replaced it, but it didn't work. When I took a closer look, I saw that I had used a 7905, instead of a 7805. :cower:

Now, I might be able to burn a new PIC and get it back on line. Thanks for posting.
 
I used a TL866ii-plus programmer from Ebay. Available from a usa supplier for $56 us also from Amazon for the same price. It is usb powered and has a very long list of chips it can program. I'm not a programmer or engineer just load the .hex file choose the PIC16F device and then click program.
Done.

Roy
 
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I had never heard of MachTach until about 5 years ago when I purchased my Sheldon lathe. The lathe originally had a mechanical tachometer in the headstock cover. The later model of the same machine had an electronic tachometer in the same location. I tried for several months to find enough parts to either replace the original, or upgrade to the electronic version, but had no luck.

In my searches I ran across MachTach and decided to give it a try. I purchased a kit complete with the sensors, power cord, and enclosure. I'm not all that well versed in electronics, but is was easy to follow the instructions and complete the project. I mounted it in the location of the original tachometer and fired up the machine. It's worked flawlessly from day one.

A couple years ago I was looking for another one for each of the milling machines. At the time the website was down, but all the rumors were that it was temporary. Apparently it was more than just a temporary glitch. I never did get additional tachometers, and still use the approximate readings on the variable speed drives.

I doubt that I have the where with all to recreate what he has done even though he has made all the documentation public.

Here's a picture of my Sheldon with the MachTach tachometer installed in the location of the original mechanical one.

DSC00013A.jpg
 
If a bunch of you get together to have pc boards made the cost will be minimal, especially if the parts are ordered from Digikey in multiples of 10 or 100. Maybe $30 per machtach or so. I have 2 on my machines and one spare kit just in case. I purchased them from Tom about a year before he quit selling them. There are some china pc board houses on youtube advertising very low prices on boards. The only down side is shipping time.

Roy
 
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To open the PCB files use the free PCB software ExpressPCBPlus at:

These are the people who make the boards for Henry Arnold. Henry will tell you how to do it and how to get the best price on the boards. Contact him through Thingiverse.

Roy
 
Also spoke to him after he closed down making the MachTach, in my opinion one of the best tach/SFM units at the price level, but just too much competition from the Asian sellers to continuing making them. I have also used the Tachulator in subsequent builds, but the MachTach is more versatile to different machines. The Tachulator only comes with an optical reader although I have converted them over to magnetic sensors. Asked him to burn a batch of MachTach control chips for me since I do not have a PIC programmer. If someone wants to go in on a run of the circuit boards, I would be interested in 5-10 boards. The price goes down the larger the batch.
I would be interested in a couple, myself.
 
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