Molex Connectors

[jgttrey]

I'm building a little cell-checker pressure pot. As planned, it gives me the option of either using a separate black box with three 0-200 mV voltmeters or, using a different cable, plugging into the rebreather head and reading voltages on my handset.

Looking for a (hopefully) easy source for both male and female 3 pin molex connectors. There are six million options and I'm having particular difficult with the male side, which has the little polarity tab. I'd rather not buy them 1000 at a time and I'm getting crosseyed trying to sort through the options. If they were already wired with pigtails, that'd be even better.

Any suggestions about convenient sources would be appreciated.

 

[lowviz]

1) Does it have to be Molex? The pins (both male and female) are best crimped with a special Molex tool that wraps and crimps the wire and also wraps around the insulation to help relieve stress on the wire. The connectors and pins are sized according to wire gauge. Molex is a solid, inexpensive, mass termination product. It may benefit you to pick a different connector that is more expensive per part, but one that doesn't require special tooling. It could be less expensive overall.

2) Are you going to solidly mount one of the connectors to your pressure pot?
3) What kind of plug is on your RB head?

https://www.newark.com/browse-for-products

You can very likely find what you want in an ancient junked computer.

 

[Mouth Breather]

I bought these for replacements on my Revo: US $5.46 14% OFF|50sets 2510 2.54mm Pitch Side Entry 3Pin Connector 100mm To 250mm with 1007 26AWG Electronic Wire Cable 3AW Pin Header-in Connectors from Lights & Lighting on AliExpress

 

[macado]

Easy. Order from DigiKey.

Here are the part numbers for Molex pins/connectors. Make sure you buy a quality crimping tool. The cheap ones will suffice but buy some extra pins incase you mess up.

Molex KK 2695 Series .100 connector (part 22-01-3037)
0022013037 Molex | Connectors, Interconnects | DigiKey

Molex Non-Gendered Contact Gold 22-30 AWG Crimp (part 08-56-0110)
0008560110 Molex | Connectors, Interconnects | DigiKey

If you need the other side of the Molex connector..
0022122034 Molex | Connectors, Interconnects | DigiKey
0022012031 Molex | Connectors, Interconnects | DigiKey


Parts
WM2001-ND CONN HOUS 3POS .100 W/RAMP/RIB Price. $0.11
WM1129-ND CONN 22-30AWG CRIMP GOLD $0.23
WM2712-ND CONN HEADER R/A 3POS 2.54MM $0.77
WM1576-ND CONN HOUSING 3POS .100 W/O RAMP $0.17

As you can see this stuff is super expensive.. Buy 50 of them and you'll have a lifetime supply.

This is the cell checker that I built. It's not pretty but it gets the job done.
http://wrecklessdiver.com/building-50-o2-cell-checker/

 

[Mouth Breather]

@macado That cell checker info is super interesting, thanks for that

 

[jgttrey]

Thanks all.

1) Does it have to be Molex? The pins (both male and female) are best crimped with a special Molex tool that wraps and crimps the wire and also wraps around the insulation to help relieve stress on the wire. The connectors and pins are sized according to wire gauge. Molex is a solid, inexpensive, mass termination product. It may benefit you to pick a different connector that is more expensive per part, but one that doesn't require special tooling. It could be less expensive overall.

2) Are you going to solidly mount one of the connectors to your pressure pot?
3) What kind of plug is on your RB head?

https://www.newark.com/browse-for-products

You can very likely find what you want in an ancient junked computer.

Yup, gotta be Molex. The cells have the 3 pin Molex connector and so, of course, does the head. I need to plug the cell checker into the head so that it reads the pressurized cells. Basically, it's a Molex extension cord, with one end inside the pot.

I bought these for replacements on my Revo: US $5.46 14% OFF|50sets 2510 2.54mm Pitch Side Entry 3Pin Connector 100mm To 250mm with 1007 26AWG Electronic Wire Cable 3AW Pin Header-in Connectors from Lights & Lighting on AliExpress

That's the one. Thanks. Perfect. Saves me some terminating trouble.

This is the cell checker that I built. It's not pretty but it gets the job done.
http://wrecklessdiver.com/building-50-o2-cell-checker/

@macado, I had seen your blog and based my design principally on it, with some tweaks from the ones the RBW thread. Great stuff.

I was hoping that there were just some pre-wired versions so I didn't have to fuss with it. I'm building the pot so it can connect to either the head or to a standalone box with 3 voltmeters. That might be useful in diagnosing certain issues. I'll post some pics when I'm done.

The pot setup is much like yours. A bit smaller filter housing. I found a cheap needle valve that I'll O2 clean and use and I'll probably put the OPV on the opposite side. I'm also going to 3D print a cell holder -- at least that's the plan.

p.s. Would love to get a copy of whatever Excel spreadsheet you use to graph the results and calculate linearity. That'd save some time for sure.

 

[jgttrey]

So, quick update. I used the pre-connected Molex connectors that @Mouth Breather suggested and it definitely made it easier.

I 3D printed a cell carrier that fits neatly on the inside of the pressure pot lid. O2 enters through the middle, goes down through the carrier, and circulates up around the edges. Should give a good purge. I used epoxy to attach the molex female connectors to the underside of the carrier.

The wiring coming out of the pot is also terminated with molex connectors so I can plug into my head or a stand-alone box with 3x 200mv voltmeters.

So, thanks for all the help.

One last request, though.... If anyone has a good Excel spreadsheet to log and graph the results, that would be much appreciated.

Joe

 

[The Chairman]

Don't be afraid of crimping. This is my favorite crimper for the Molex, and all 2.54m connectors: https://smile.amazon.com/gp/product/B00OMM4YUY/ref=ppx_yo_dt_b_asin_title_o05_s00?ie=UTF8&psc=1

I 3D printed a cell carrier

Is it on thingiverse? If not can you post the file here?

 

[jgttrey]

That's a good looking tool. I wasn't really afraid to crimp, it was just easier and cheaper to spend $6 on 50 that were already done than to buy the connector parts and then do the crimping too. I may get the tool anyway for future projects. There is something very satisfying about the right tool for the job....

I'll post the STL for the cell platform on Thingiverse when I get home and put the link here.

Honestly, it was embarrassingly simple. I didn't include the holes for the wires in the print because it was easier to figure out where to put them afterwards and drill them out.

It's also custom for the particular filter housing that I used, so I'll post the link to that as well.

 

[The Chairman]

That's a good looking tool.

And it works quite well. I created a 12 LED LightRing for my octopi that I use with my Tevo Tornado and wanted to use a three wire ribbon to connect to my Pi. I have write up on in in our 3D printing forum. It takes seconds to use per connector and I like that I have control over colors and length.