HeaterMeter Hardware v4.2.4


 
Jeff Baker said:
Does the ambient temp take away one of the temp probes?
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Not on the 2.5mm thermistor jacks. When you plugin a probe, it breaks the circuit for the ambient sensor. You just need to make sure you choose the correct probe preset in the web based config screen.
 
Yes, typically the ambient temp is wired to the last probe, but the way you wire the thermistor on the probe jack you can still plug a probe into the jack and use a 4th probe (must select the proper probe type in the HM config).
 
I've added an image to the assembly album with various voltages around on the board to assist in troubleshooting a new build. Test the first column of voltages without the Pi attached.
 
So I just ordered the board from Tindie which is great. I need the entire order from Mouser but what other parts are required for the thermocouples? The jacks I guess? Just trying to get the full picture.

Thanks!

Neil
 
The thermocouple board from tindie includes the thermocouple jack. You'll still need the entire standard Mouser cart, and the entire set of Digikey parts except one fewer 2.5mm jack (3 needed).
 
NeilHeuer said:
Wait so it only supports one thermocouple?
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Thermocouple pit probe support - For those willing to try their hand at surface-mount soldering, the pit probe can be hardware configured to use a thermocouple.
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Any of the inputs can be set up to be thermocouple, but the v4.2.4 board only has pit probe thermocouple built in. If you want the other 3 to be thermocouple-enabled, then you'd need to build your own custom external board.
 
And I am currently working on such a board.
I am creating a small board for each input that will have the themocouple circuitry and themocouple jack.
I am also thinking about a board with 3 themocouple inputs and you just populate the parts for 1 2 or 3 thermocouples.
 
Frank Giacinto said:
And I am currently working on such a board.
I am creating a small board for each input that will have the themocouple circuitry and themocouple jack.
I am also thinking about a board with 3 themocouple inputs and you just populate the parts for 1 2 or 3 thermocouples.
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Yeah it isn't difficult, just the same schematic duplicated. I didn't do it on the HeaterMeter PCB because the space needed to fit in all the components meant making the PCB a lot bigger (bounding rectangle) and removing the PROBE pinheader which ironically reduced flexibility. One could be whipped up in minutes by copy pasting, but the question then becomes how to secure it physically because the connectors have a large insertion force and it needs to fit inside a case still.
 
Bryan Mayland said:
Yeah it isn't difficult, just the same schematic duplicated. I didn't do it on the HeaterMeter PCB because the space needed to fit in all the components meant making the PCB a lot bigger (bounding rectangle) and removing the PROBE pinheader which ironically reduced flexibility. One could be whipped up in minutes by copy pasting, but the question then becomes how to secure it physically because the connectors have a large insertion force and it needs to fit inside a case still.
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I would like 4 thermocouple probes otherwise its like driving on one good wheel :)

Neil
 
http://www.ebay.com/itm/Connector-Thermocouple-U-Calibration-Mini-SMP-PCB-Vertical-Mount-Lot-20-/351049592732?pt=LH_DefaultDomain_0&hash=item51bc2faf9c

I know this would need a board modification, but getting vertical connectors would save some space then using horizontal connectors, although it would still need a bigger HM pcb and a bigger case, they would be better vertical if someone decided to try a modified HM for multiple K thermocouples.

Edit::::the ones linked show U calibration, not sure how that would be different then K, but im sure they make K ones too
 
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You need one amp per thermocouple, the HM board only has one amp, so 4 thermocouple connectors do you no good. If you want 4 thermocouple probes I would suggest you buy/build an external thermocouple board that has 4 amps and 4 jacks on it, then connect it to the HM via CAT5 cable.
 
I am aware of the vertical connectors. Horizontal was chosen because:
-- It is much sturdier. Vertical connectors apply a lot of torque on the PCB during insertion. The HeaterMeter board isn't terribly secured inside the case. The combination of the two could cause problems either bending the connector itself or other parts or connectors.
-- There's no space for the amplifier components anyway

I estimated that a very small percentage of people would try to solder the thermocouple parts, based on the fact that most people building HeaterMeters have had no soldering experience at all and are reluctant to even try giant through-hole soldering. The PCBs would be a lot more expensive to support something most wouldn't use. Also, adding 4 thermocouples increases the cost of parts by like 50-70%.

There are downsides to thermocouples as well, like the HeaterMeter implementation can't go below ~45F, and they have less resolution per ADC at some temperatures (but more at others). They're not perfect.
 
I'm with you on that Bryan, I think you should only need one thermocouple. Reason being, the thermocouple is only a requirement for high heat cooks, and the leads on the probes (and thermocouples) can't handle being inside the grill during high heat cooks, so when doing high heat cooks you end up using just the pit probe. The other reason I wanted a thermocouple is because high heat cooking and MOISTURE kills even the High Heat Maverick probes pretty rapidly, however, I have had a Thermoworks Pro probe outside all summer and it's still good as new! WAY more weather resistant than the Maverick probes. I know some people say they had problems with the Thermoworks probes, but mine have always worked great on every version of the HM that I have built, and they have been the most resilient probes I have bought, the only time I have killed one is when I took them way over their rated heat range...
 
Bryan,

I purchased one of the boards on Tindie, have you shipped them out? I cant wait to build got the rest of the parts ready to go.
It will be my second Heatermeter.

Thanks for all you hard work, I use your Amazon link on most of my purchases, with the rest going to the TVWWB Amazon link.

Dale
 
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Dale Ward said:
I purchased one of the boards on Tindie, have you shipped them out? I cant wait to build got the rest of the parts ready to go.
It will be my second Heatermeter.
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Yeah, does Tindie not send out an email with the tracking information? Shipped on the 25th, I'll PM you the tracking information.
 
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Bryan Mayland said:
Yeah, does Tindie not send out an email with the tracking information? Shipped on the 25th, I'll PM you the tracking information.
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I received my board today but I am just down the road. Glad it came so quick. Ordered the parts from mouser. Question why is the jack not soldered in?

Thanks

Neil
 
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