Modiying to use ET-732 probes


 
K

Krys

New member
Hi All,
I am new to the forum but I have been reading all about the HM and the R pi. I was about to order a wifi unit from a nice guy in China until I came across your work here. I have to say that I commend you all for taking on the project and helping so many others along the way.

I decided to build my own unit. I am about to place my orders through mouser, digikey, ebay, amazon, etc. I currently have the Maverick ET-732 already, but no replacement probes as of yet (I’ve been gambling on my probes to last throughout my cooks). I was hoping to order and use ET-732 probes for the project so I didn't get anything mixed up and have to keep track of multiple probes, and also have probes to spare.

I recall reading that to make the probes work in the jacks, I would have to pull them out slightly. I also recall reading that the resistors for the jacks are rated for the ET-72/73 probes (10K, if I am following the plans correctly). I also recall a recommendation to use a different resistor or something on the board so the et-732 probes work properly throughout their heat range (maybe 22K).

1. If so, would anyone know the parts needed and the product numbers with mouser or digikey? ( I only ask because this is my first DIY electronics project and I would hate to mess it up).

2. Also, would I need to use an alternate ‘ambient temperature’ thermistor (to match the above resistors) to reduce conflict, and for ease of operation?

3. Is using ET-732 probes realistic? Or, should I just make the change to the ET-72/73 probes and abandon the ET-732? and what part number?

I do appreciate any and all assistance that anyone can lend me.

Thank you,
Krys
 
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I use 732 probes with little issue. The probe values are set in software so no need to change any of the electronics or resister values. As for the plug length, it depends on your implementation of HM. The jacks on the current HM4 don't have a hard stop inside so you can plug the probe in too far and it doesn't make contact. With a little practice you can feel how far to push them in or do like some have done and put a collar on the probe or the jack to prevent this. I still have my setup from a previous HM3.2 and have a separate probe assembly and the jacks on that have a stop in them so you can't push them in too far. I'm not sure the part number but they were from Mouser and I bought them in a lot of 50 from eBay. Oh, and as for ambient, that's more informational. It's up to you if you're interested but not required. You can install it if you like and when you plug in the probe, the probe will override.
 
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Krys,

The ET-732 probes work fine, but they are a little more susceptible to kinked wires. You just need to be a little more careful with them. I prefer an ET-732 for the pit probe as it does have more temperature range than the ET-72/73. However saying that the ET-72/73 probes seem to be more robust and work perfectly fine.

If you already have the ET-732 and would like to just keep the one type of probe I think that will work and be convenient to not have to keep track of the two different probes. They do look very similar.

As for the biasing resistor, the 22k value does center the ET-732, providing better low temperature accuracy, it isn't required either. If you choose to use them you also need to change the value on the setup tab.

Really it comes down to personal preference, both probes work great, 10k works for both probes as well. The 22k resistor will make the ET-732 probe have a similar lower temperature accuracy as the ET-72/73 with 10k. It only matters with temperature < 100F so once everything gets going the difference really can't be seen.

hopefully some of my ramblings make sense. If you are still interested in using the 22k resistors let me know and I can find the mouser part for you.

dave
 
Thank you both! This all makes sense, and is very helpful in understanding the differences.

I will probably go with the 732 probes if I can find them at good price including shipping costs (if you know of a place). Otherwise, I will go with the ET72/73 (depending on price as well).

For now I will be doing hot smoking and bar-b-que, so the low end is not priority. But If I get into cold smoking, I may build another unit or change the resistors. If you know the proper part number for the 22k resistor, it would be appreciated for future reference.

Thanks again, Krys
 
I bought mine from Todd here:

http://www.amazenproducts.com/

I also use his AMNPS for cold smoking, cheese, bacon, sausage, etc.

dave

Krys said:
Thank you both! This all makes sense, and is very helpful in understanding the differences.

I will probably go with the 732 probes if I can find them at good price including shipping costs (if you know of a place). Otherwise, I will go with the ET72/73 (depending on price as well).

For now I will be doing hot smoking and bar-b-que, so the low end is not priority. But If I get into cold smoking, I may build another unit or change the resistors. If you know the proper part number for the 22k resistor, it would be appreciated for future reference.

Thanks again, Krys
Click to expand...
 
I forgot to mention, I live in Canada, and Amazenproducts wants $31 for shipping. I will keep searching, it is the last parts I need to order for my HM 4.0
 
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