Hi,
I bought “Sparkfun MLX90640 110 Degree 24x32 Inferred Thermal Temperature Sensor” from Ubuy.com a few days ago.
I have tried to run that sensor using Raspberry Pi 4, the power light is turned on after giving the wire connections, but after ensuring all the correct connections. all the pins in i2c are high as given in the screenshot below.
I have also tried to run the sensor using a different ESP32 microcontroller, but I am getting the same type of error “not detected at default I2C address” .
I have tried many ways to run the sensor. Changed the wires, connected through breadboards, added resistors, changed the frequencies inside the code, but none of them worked. I am really confused about what the issue is now. I am genuinely seeking help from you guys. Thank you so much.
I have followed these two types of tutorials for the wiring connections of Raspberry Pi 4 and ESP32
https://makersportal.com/blog/2020/6/8/ … d-mlx90640
https://www.instructables.com/Infrared- … 0640-and-/
I had the same problem, doing tests with a fully functional 3.3V Teensy 3.2 and the Sparkfun library simple example. After triple checking all wiring, voltages and continuity, I asked for a replacement, which SparkFun kindly supplied. The new one did on some occasions respond to I2C commands, and once even gave a couple of images before refusing to respond further, but only rarely out of many attempts. I finally gave up.
I’ve read elsewhere that the MLX90640 sensor can be unreliable, but the current batch seems to be especially problematic.
jremington:
I had the same problem, doing tests with a fully functional 3.3V Teensy 3.2 and the Sparkfun library simple example. After triple checking all wiring, voltages and continuity, I asked for a replacement, which SparkFun kindly supplied. The new one did on some occasions respond to I2C commands, and once even gave a couple of images before refusing to respond further, but only rarely out of many attempts. I finally gave up.
I’ve read elsewhere that the MLX90640 sensor can be unreliable, but the current batch seems to be especially problematic.
I am tired after many attempts as well!
May I know how did you contact them for the replacement? By email?
Customer product support.
No need to quote my post – anyone can see it.
I am having a similar issue with the 55 degree sensor. Mine is intermittently shorting SCL to ground, resulting in permanent clock stretching. I think if SDA were shorted to ground, it would give an ack from all addresses, like yours were doing.
It might be repairable by desoldering the sensor from the board.
Please try desoldering and let us know. I bought a third MLX90640 (55 degrees) from Adafruit and had the exact same problem, third time in a row: some intermittent I2C responses, maybe a couple of complete images, then nothing. It appears that these days, Melexis does not bother to test anything they ship out.
Yet another replacement is on its way, from a new shipment of sensors. Fingers crossed!
I have the same issue.
Bought from SparkFun the Redboard and several sensors including the 90640 55 degree version.
Connected some of them with qwik connection and used i2c scanner to check them
All works until I connect the 90640 and then nothing is found.
I check and found out the the SCL is short to the GND.
The board is quite simple so I am quite sure the problem is with the sensor itself.
How do I contact SparkFun support ?
Should I asked for replacement or money back as it sounds like a new will also make problems.
The latest MLX90640 replacement arrived, and it works as advertised, so far without any glitches at all.
There was definitely nothing wrong with any of my experimental setups.
Thermal self portrait:
++++++++++++++++++++++**++++++++
++++++++++++++++xxx+++++++++++++
+++++++++++++x%####%++**++*+++++
++++++*++++++x######+++++*++++++
+++++*+*+**+x%%%##%%x++++++*++++
+++++**+*+*+xxx%%%xxxx++*+*+++++
++++++*+***+x%%%%%%%#%+++**++*++
+++++++++*++%###%####%++++++*+++
++**++***+++#########%+++***++++
++++*+*+++*+##########++*****+++
++++++++++++##XX#XX##%+++***+**+
***+++++++++##XXXXX##%*+*+***+++
+++++++++++x##XX#XXX%x+*******++
++++++x++xxx##XXXXXX%x++*****+++
++++x+xxxxxx#XXXXXXXxxx+++*+++++
+++++xxxxxxx##XXXXX#xxxx+**+*+++
++xxx%xxx%%#XXXXXXXX%%xxxx++++++
+x%%###%#####XXXXXXX###%#%x+++++
x%#############X########X###xx++
%%#################X###X####%x++
%##############X##############xx
##################XX######XX##%%
###X#X##########X#XX######XXX##X
X##X######################XXXXXX
For my board, removing the sensor cleared the short between SCL and ground. The SCL trace on the board must have been making contact with the grounded metal case of the sensor.
I stuck a piece of thermal tape to the bottom of the sensor and soldered it back on, and now the board is working flawlessly.
@jwclough how did you desolder it. Could you provide any pictures? Thanks.
I’ve also discussed the issue with my seller Ubuy, I am waiting for their final reply.
If you have access to a hot air rework station, that would be ideal.
I don’t, so I just used a soldering iron to melt the solder on the four leads attaching the sensor to the board, and sucked up the molten solder with a solder sucker. I had to add a bit of fresh solder to help get it all molten. Then, after removing as much solder as possible, I used the iron to heat all 4 pins at once while gently pulling on the sensor. If you need more desoldering advice, youtube is an excellent resource.
To insulate the bottom of the sensor, I used some double-sided thermal tape (the kind used for attaching heatsinks).
Unfortunately, on my latest example of an intermittently defective MLX90640, neither SDA nor SCL are shorted to ground, and I can see the 4.7K pullups to Vcc. So those connections do not appear to be the problem.
I purchased one of your products named “SparkFun IR Array Breakout-55 Degree FOV, MLX90640 (Qwiic)” and directly used that Thermal Camera with Raspberry Pi 4 by enabling I2C as well. But when I run “sudo i2cdetect -y 1”, it doesn’t appear in the console.
Initially, I didn’t find the “JST SH 4-pin Cable with Premium Female Sockets”. So I soldered the Thermal Cam with Male pins to connect with F To F jumper cable. Afterward, it’s showing the power light but can’t be showing in the i2c detected device sensor list. Also, tried with different Raspberry Pi 4 devices as well but the output was the same.
Can anyone please help us to connect Thermal Cam(MLX90640) with Raspberry Pi 4?
Furthermore, I found one of the products named “SparkFun Qwiic HAT for Raspberry Pi” is used for connecting the SparkFun devices with the Raspberry Pi device. So, Can anyone guide us in connecting the “SparkFun IR Array Breakout-55 Degree FOV, MLX90640 (Qwiic)” device with “Raspberry Pi 4”?
Do you have an ohm meter?
Try disconnecting the board from your Pi and measuring resistance between the GND pin and SDA and SCL individually. It should be an open circuit or high resistance. (>10K ohms)
Currently, We don’t have an OHM meter to measure such things. But I will manage those things and update you further with the measurement of GND, SDA, and SCL pins.
Furthermore, I have some initial questions in my mind about this. Can you please provide some clarity for my understanding?
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Is this SparkFun MLX90640 55 Degree Sensor(Thermal Cam) directly connect with Raspberry Pi 4?
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Is that we required Qwiic HAT to connect SparkFun MLX90640 55 Degree Sensor(Thermal Cam) with Raspberry Pi 4?
We measured the things which you have mentioned previously and it was as below:
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Resistance between GND and SDA Pins: 0.0 (NIL)
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Resistance between GND and SCL Pins: 3.0
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Resistance between GND and 3.3v Pins: 12.4
Let me know if you need any more updates on it.
Those sound too low to me, if you purchased the board directly from our website, [fill in the form on this page with your order number and the URL to this forum post and we can help.
If you purchased from a distributor, you will need to let them know you have a bad sensor and that we authorized a replacement and they should be able to help.](Return Policy - SparkFun Electronics)
