Fool_4's automatic PE device

I have a confession to make, to all those who have complimented my techie abilities. This project was born of ineptitude, in that I could not seem to make a working hanger! Could I be missing the “internal structures” I keep hearing about? I just kept ending up with a blood blister looking head, and we are not talking extreme weight at all!

F4

Murphy must have a little ass dick, because he sure has been visiting me in my PE development efforts tonight. I only have SINKING 4-20ma outputs and the nice neat little chicom PWM DC drive I was planning to use is voltage input, something funky like 0-4.6V, any way long story short with sinking only outputs there is no way (without a signal conditioner) to do the usual 250ohm accross it’s leads and rock on as the 0V is common to the supply rail on both PLC and drive. In my throws of trying to devise some voltage divider ckt or another the little mother smoked on me. I dug all around and I am unable to locate anything else, even parted out and old non-working Dewalt cordless drill but it was not suitable once on the bench. I will have to make a trip to Minarink and get one of those little KB Electronics el-cheapos (when I have the funds). I will probably buy two, one to run the motor and another to do the PWM for the cuff heating. I did find an RTD input card after all :)

For tonight I am done messin with it.

F4

PS the first test run last night used this drive but I used a speed pot instead of having PLC control of the reciprocation speed. Trying for the last few hours to bring this under control is where I killed the drive.

Minarik, in their infinite wisdom, has decided to no longer stock anything in my locality, and the prospect of involuntary receptive anal sex that a trip to Grainger would mean, leaves me few immediate options. I am now installing the Arduino programming suite and making ready to set up to take analog in and generate PWM outs to drive an old Vantec H-Bridge module. So yes I am having to re-invent the wheel as it were. One advantage is that this bridge is of a really high current rating and is in fact a double bridge, here enters the PWM to drive the heater.

F4, hacking.

Testing my Arduino code. These things are really wonderful, in a pinch you can bodge one into virtually any role.

What kind of hanger?

Kinda a hybrid, made with what all I have laying around, a variant of the “Captain’s Wench” would best describe it. Just didn’t work at all :(

F4

I have a suitable DC drive ordered for the reciprocation, I am not liking the new PWM drive that I built much. The other chicom unit I killed was apparently a little more motor purpose specific than I gave it credit for, it must have been doing IR comp and had anti-stall cky inbuilt. Color me impressed.

I am worn out, I am thinking a couple days without working on this thing. I need to go cover a few “real” calls (so I can rest). I do not remember ever working this “HARD” on anything else.

F4

Just can’t leave this alone, here is one of the cuff heating element and RTD being wound and “potted” in E6000. If you have not used this before, I highly recommend it, it’s got the look and consistency of RTV silicone, but with an attitude! Pulling strings of this stuff off results in breaks and snaps like breaking rubber bands. This stuff is tough!

F4

Try an AFB hanger, it is the most simple and works fine.

Thanks Marinara, happen to have a link, I don’t recall seeing the build of that one.

Here are a couple photos showing the cuff after the nichrome and RTD were incorporated. Also I found a 4A 12V power supply to power the heat with. The finished element ohmmed out at 3.5ish, so 12V will push about 3.5 amps and dissipate around 41 watts into the cuff (just about perfect).

Gone now are the tywrap bands that were only there to allow cuff serviceability as now the rails have been trimmed to make cuff removal possible with the rails in place. This modification does make for better visibility for sure, in case anything “un-toward” were to be going on in the machine’s grip.

F4

AFB Hanger Concept - 2002 Site - Tom Hubbard

Does anyone have any ideas on how to get a good connection to one’s “unit” while it’s contained in my device? I looked at strips of conductive rubber ran through the cuff, but these would allow loss of vacuum at an increased rate. I am able to set the vac suction to anything from 0-24.4 “hg but don’t want a situation where the pump is being overworked due to leakages. Bear in mind that to run strips inside the chamber would mean intermittent and poor connection and unpleasant zapps and hot spots. The connection needs to be firm and persistent. The electrodes need to be very dynamic indeed, I am out of ideas.

Maybe just a base ring? This would allow currents into the ligament area but no current through the tunic. Also where should the opposing electrode go? I am not fond of the most obvious location.

F4

Thanks Marinara, that does look the business.

F4

Come on guys, someone has got to have an answer to my conundrum. Have considered a urethral insert but it would have to be attached in the chamber and end before the cuff (so as not to lacerate the urethra when the cuff clamps down), meaning if the stroke ever went far enough to have the head in the cuff, the electrode would fall out and become mis-aligned for sure. And a urethral electrode is intimidating to many as well.

F4 thinking aloud.

Here are photos of my cuff compressor, old vs. New. (Harbor Freight trip behind me). The new one is nice and quiet and does maintain about 50psi in stead of the 150+ from the garage monster. This lessens my fears of having a coding error remove something important to me.

F4