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JCDammeyer's 42 projects
- Thread starter jcdammeyer
- Start date
@jcdammeyer - on a serious note (must be getting close to my bedtime), my understanding is that most silicon sealants harden when humidity reaches the adhesive. All it takes is an open surface somewhere - even at one end of a tube. Moisture from the air will diffuse through cured silicon to reach uncured silicon which will then cure too. In essence, it's really only a matter of time.
Not all adhesives use moisture as a catalyst. But the principle is the same. They will all cure eventually if the catalyst is there.
Not all adhesives use moisture as a catalyst. But the principle is the same. They will all cure eventually if the catalyst is there.
Dabbler
ersatz engineer
true. it works best it there is a small thickness put on first, and given 5 minutes to start to catalyze, then another layer, etc. if it isn't skimming over when the next coat is applied the layers bond.
We're talking 3/16" tubing here with a roughly 3mm diameter wire assembly going through. So it would be a thin layer of sealant. I found some exhaust sealant at Cdn Tire. Good to over 500 degrees. $10 or so experiment.
But again it's the issue of getting it inside the tube without air bubbles etc so that it ends up leaking.
I've thought about mixing up epoxy and using my vacuum tank to first remove the bubbles. Then stick the end in the mixture and turn on the vacuum again. Let it suck the fluid up the tube displacing the air. But it would still need an hour to harden.
Bit of an update with some pictures.
After soldering in the T into the copper I found that the hot end of the radiator leaked. As Chris M. loaned me his VEVOR flanging kit I thought I'd take a stab cleaning up what I had obviously done poorly. But his kit doesn't come with 74 degree forming tool.
So I made one.
Still couldn't find my soapy sud bottle so I pulled out a clean one and mixed up some more. I think not enough water but now I only have a tiny bubble at that same 74 degree fitting.
Meanwhile I turned a steel plug and used a ferrule to plug up the hot end fitting until I get the probes working. On the cold side the 3D printed plug is still in place and not leaking. On the hot side it actually got hot enough, deformed and blew out. Found it on the floor a bit later back to its original shape.
And on the display front... Still a bit of software to do and a second probe to build but these displays are sweet.
Just playing around with the SPI messages to show negative or positive numbers. Here's a scope photo form the logic analyzer part that decodes SPI. First Byte is either A5 for no negative or A3 for just the 1. The 'A' is to put the decimal place where it is and full display intenstity.
More as it happens.
After soldering in the T into the copper I found that the hot end of the radiator leaked. As Chris M. loaned me his VEVOR flanging kit I thought I'd take a stab cleaning up what I had obviously done poorly. But his kit doesn't come with 74 degree forming tool.
So I made one.
Still couldn't find my soapy sud bottle so I pulled out a clean one and mixed up some more. I think not enough water but now I only have a tiny bubble at that same 74 degree fitting.
Meanwhile I turned a steel plug and used a ferrule to plug up the hot end fitting until I get the probes working. On the cold side the 3D printed plug is still in place and not leaking. On the hot side it actually got hot enough, deformed and blew out. Found it on the floor a bit later back to its original shape.
And on the display front... Still a bit of software to do and a second probe to build but these displays are sweet.
Just playing around with the SPI messages to show negative or positive numbers. Here's a scope photo form the logic analyzer part that decodes SPI. First Byte is either A5 for no negative or A3 for just the 1. The 'A' is to put the decimal place where it is and full display intenstity.
More as it happens.
Now I have to wait for the 3D printer to do its thing for the bottom. Then do the top. Hopefully everything will fit. Connection to the control board is via DB-9P which will supply power and the SPI signals.
Will likely have to change the LM7805 to switching regulator version as this one gets rather warm which isn't good for PLA.
Will likely have to change the LM7805 to switching regulator version as this one gets rather warm which isn't good for PLA.
Looks like my CAD and measuring skills need a bit of updating. Display doesn't quite line up with the holes. And forgot about shrink factor in 3D printing so the PC board mounting holes are off just a tad (0.0625" or so).
The xIM series unit I'm using this was originally configured as a prototype for a 4 channel DHT-22 RH+Temperature module along with 1 Thermister and a few other I/O. I took that software from 2016 and removed 3 of the DHT-22 definitions and added jumpers to bring out SPI and re-enabled the second thermister.
Forgot how many software changes I'd made to the original xIM code to do that so it took a while to get everything working. Didn't help that my ZBOOK laptop decided to no longer boot the OS either so that's wasted a lot of time and still isn't working.
Anyway. Here we are. Inlet and Outlet Thermister Temperature readings. Now just to cycle periodically through RH+ambient_tempearture and also tank pressure.
Still a few bugs like not showing negative temperature (like my shop would ever get that cold). Mounting everything. Likely 42 things left to do.
Forgot how many software changes I'd made to the original xIM code to do that so it took a while to get everything working. Didn't help that my ZBOOK laptop decided to no longer boot the OS either so that's wasted a lot of time and still isn't working.
Anyway. Here we are. Inlet and Outlet Thermister Temperature readings. Now just to cycle periodically through RH+ambient_tempearture and also tank pressure.
Still a few bugs like not showing negative temperature (like my shop would ever get that cold). Mounting everything. Likely 42 things left to do.
Update on that photo above. Didn't really show the AM2303 sensor module (AKA DHT-22) and the second probe currently connected with clip leads.
Here are the values as sent over CAN bus in CANOpen format and captured by the CANView USB module.
Not sure why the thermister temperatures don't match. Something with the RM CAN software scaling is not quite right. More work required there.
Here are the values as sent over CAN bus in CANOpen format and captured by the CANView USB module.
Not sure why the thermister temperatures don't match. Something with the RM CAN software scaling is not quite right. More work required there.
Isn't that mismatch within the margin of error for thermistors?
Easily both the thermistor and the two 1% resistors making up the voltage divider.
The PC display errors are due to me not reading the user guide. The values now match the display.
140mower
Don
Try not to let the wife know that you read the manual, it'll be expected of you all the time.....
Actually badly written software. I've selected that the first two bytes in Little Endian Format are a signed number that goes from -32768 to +32767. Because I've selected Int16 the Unit fields at the far right should be changed to read:
"Value 0000 Hex" and "Value FFFF Hex" but even that's misleading.
I really need to key in the values like this:
Which produces this from the binary hex value 0x00D9 which in decimal is 127.
The program is just nice in that it can take CANOpen protocol messages and show engineering units that are in the messages.
A bit of progress after I found one silly mistake that kept the CDS light sensor cell from reporting it's voltage reading. Once that was done all went well.
It's only a 27 second video and the description on the you tube page describes what is happening.
It's only a 27 second video and the description on the you tube page describes what is happening.
Here's the complete status display via CAN messages.
Now to finish the probes, mount it all somewhere and finish the wiring.
That is the hardest part of this project.
Now to finish the probes, mount it all somewhere and finish the wiring.
That is the hardest part of this project.
Well rats! Looks like another software issue with linearizing the Thermistor. The radiator inlet temperature went from 23C up to 99.9C and then stopped. The outlet went from 23C to 24.4 so we know the cooler is working. The reflective infra-red temperature module showed 115C on the compressor head and even 105C on the brass outlet. The outside of the brass fitting holding the Thermistor only went up to 45C.
And note to self. Put a small catch can or hose to a can under the water separator after the cooler. Seems when the compressor shuts off and the compression side bleeds off the outlet valve also opens and at that moment water dribbles to the ground.
EDIT: Ah. Original code was really never meant to go above 60C.
---- 10K Thermistor
3.32K, 2.49K for 10K thermistor.
(-35C,241,323R) == 0.101V
(25C,10K) == 1.575V
(60C,2484R) == 3.00V
0xFFAE, 0x204, // [4,5] Thermister scale as 32 bit integer 33882030
7600,0, // [6,7] thermister offset for R1,R2 = 5.11K
Later versions changed that to max 100C so the offset changes to 7600. If anyone is interested I can post the entire algorithm.
Will have to change the resistor divider and redo the math.
And note to self. Put a small catch can or hose to a can under the water separator after the cooler. Seems when the compressor shuts off and the compression side bleeds off the outlet valve also opens and at that moment water dribbles to the ground.
EDIT: Ah. Original code was really never meant to go above 60C.
---- 10K Thermistor
3.32K, 2.49K for 10K thermistor.
(-35C,241,323R) == 0.101V
(25C,10K) == 1.575V
(60C,2484R) == 3.00V
0xFFAE, 0x204, // [4,5] Thermister scale as 32 bit integer 33882030
7600,0, // [6,7] thermister offset for R1,R2 = 5.11K
Later versions changed that to max 100C so the offset changes to 7600. If anyone is interested I can post the entire algorithm.
Will have to change the resistor divider and redo the math.
Last edited:
I think I will have to change to thermocouples rather than thermistors. At least for the inlet temperature. The chart here shows 150C and in reality that's a max temperature for thermistors.
And as the photo shows after changing the two resistors and the scale/offset values to calculate a new resistor value based on voltage I'm not so sure the temperature readings at this high a value is actually accurate.
So time to make a K-Type thermocouple probe and swap that in.
For my kiln project (#42 of course) I do have to use thermocouples as there we know the temperatures really go high. So far this is just an arduino project or more specifically a WeMos module. On the upper right is the MAX31855 which is SPI bus output Thermocouple module. The display here just shows Set Point and Temperature. I think I have a couple more of the MAX31855 modules in the kiln project box. Just have to figure out the chip select and software for that.
Luckily I also have a Digital Volt Meter that reads thermocouples. Use it with a long probe to test melted aluminum temperature in the foundry. So rather that write a bunch of software etc. first just make a probe to replace the Thermistor one and use the meter to measure temperature.
And as the photo shows after changing the two resistors and the scale/offset values to calculate a new resistor value based on voltage I'm not so sure the temperature readings at this high a value is actually accurate.
So time to make a K-Type thermocouple probe and swap that in.
For my kiln project (#42 of course) I do have to use thermocouples as there we know the temperatures really go high. So far this is just an arduino project or more specifically a WeMos module. On the upper right is the MAX31855 which is SPI bus output Thermocouple module. The display here just shows Set Point and Temperature. I think I have a couple more of the MAX31855 modules in the kiln project box. Just have to figure out the chip select and software for that.
Luckily I also have a Digital Volt Meter that reads thermocouples. Use it with a long probe to test melted aluminum temperature in the foundry. So rather that write a bunch of software etc. first just make a probe to replace the Thermistor one and use the meter to measure temperature.