Tmp007. IR sensor used to check top surface of bed

Has anyone used the tmp007 IR sensor? I’m thinking it would be a good idea to mount on your top rail for measuring the real bed temperature. I’m not a fan of the temperature sensor for the bed, only telling me what the temperature of my underside bed is. I know you couldn’t hook this direct to the firmware bed temperature as it would cause your heater to function incorrectly. Rather I’m thinking of linking it to chamber monitor of the firmware. That way you could easily integrate the IR sensor into your firmware

What’s people’s thoughts on this?

Keep in mind that the underside thermistor is likely more accurate than an infrared sensor would be. Infrared thermometry needs to be calibrated to account for surface emissivity. This will vary for different bed surfaces…

Not trying to replace the original bed sensor. Just trying to compliment it. Finding heating takes a lengthy period and would like to know when whole bed is at temperature.

One way of dealing with this is to characterize your bed thermal behaviour by measuring top surface temperature vs bed thermistor temperature. Do it several times to different target temperatures and you will get a scatter plot of top surface temp vs. thermistor temp. You can then use this to define the required time delays or wait time. However, with the thermistor attached to the bed heater pad and even more so if the heater pad is insulated, the top bed surface temperature will always lag behind the thermistor temperature. This means that if you want to start printing at a given temperature your wait time will slightly increase.

In general, the heat-up time should be very short compared to print time, unless you use your bed to heat-up the chamber like on an enclosed Voron. Or if your prints are very small of course.

maybe some info for reading.

there are smart :nerd_face: people who made macro’s that used a bed sensor and a top sensor to calculate heat soak time

github: klipper-voron2.4-config/heatsoak.cfg at mainline · garethky/klipper-voron2.4-config · GitHub

topic post for info : Interruptible heat soak - #3 by elpeter

the github version uses a extra sensor for calculating heatsoak

edit: after inspecting the topic i saw you also commented in there, little bit of old news then :sweat_smile:

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