GT-511C3 (ADH TECH) Fingerprint scanner getting hot while connected to pl2303 usb to ttl converter

[suyog]

GT-511C3 Fingerprint scanner getting so hot immediately (70 degree celsius) while operating with pl2303 usb to uart converter. I am beginner in embedded systems, so that i dont have too much knowledge of it.

What i can do to solve this problem, Is any register needed so that it will operated in normal tempreture.

 

[Harald Kapp]

Check the reader first. Does it work on a USB port without the USB-2-UART converter in between?
If so, check the converter. Does it work with another device?

What is your system setup (which device is master, which is slave)? What is connected to the UART side of the converter?
Where does power come from? It looks like the scanner is meant to be powered from the USB port, but the USB converter ha no obvious power supply (unless it's powered from the UART connectro, but that's not clear).

Do you gave links to the datasheets of both scanner and converter?

 

[suyog]

Check the reader first. Does it work on a USB port without the USB-2-UART converter in between?
If so, check the converter. Does it work with another device?

What is your system setup (which device is master, which is slave)? What is connected to the UART side of the converter?
Where does power come from? It looks like the scanner is meant to be powered from the USB port, but the USB converter ha no obvious power supply (unless it's powered from the UART connectro, but that's not clear).

Do you gave links to the datasheets of both scanner and converter?

It will not work directly through USB, We have to use ttl leveler, so that i used usb to uart. I attached the datasheet of the fingerprint scanner and pl2303 usb to uart. take a look.
References:
Fingerprint Scanner: http://cdn.sparkfun.com/datasheets/Sensors/Biometric/GT-511C3_datasheet_V1 1_20130411[4].pdf
PL203 : http://www.prolific.com.tw/userfiles/files/ds_pl2303hxd_v1_4_4.pdf

 

[Harald Kapp]

What is the pinout of the UART<>USB converter module's 5-pin plug? How do you connect this to the fingerprint scanner (do the right signals match)?

 

[suyog]

What is the pinout of the UART<>USB converter module's 5-pin plug? How do you connect this to the fingerprint scanner (do the right signals match)?

Yeah I followed the instructions its working properly. everything is okay only problem is the module getting hot in very short time.

 

[BobK]

Can you point us to a datasheet or at least a description of the fingerprint reader. It sure looks to me like it is a USB client device, which should simply be plugged into a USB host via a standard cable.

Bob

 

[Harald Kapp]

It doesn't seem that easy.
The datasheet is linked in post #3 - and it is a very confsing one:
On page 4 it states "simple UART & USB communication protocol".
The pinout on page 36 shows UART_Tx and UART_Rx data signalsonly (plus power).
The command description shows no reference to USB, only HEx values supposedly to be transmitted and received via UART.
I guess the reference to USB is intentionally deceptive and means exactly what suyog is trying to accomplish: tunnel UART through USB via a USB <> UART converter/adapter.

the module getting hot in very short time.

Which part of the module exactly is getting hot? And how hot? Can you still touch it?

 

[suyog]

It doesn't seem that easy.
The datasheet is linked in post #3 - and it is a very confsing one:
On page 4 it states "simple UART & USB communication protocol".
The pinout on page 36 shows UART_Tx and UART_Rx data signalsonly (plus power).
The command description shows no reference to USB, only HEx values supposedly to be transmitted and received via UART.
I guess the reference to USB is intentionally deceptive and means exactly what suyog is trying to accomplish: tunnel UART through USB via a USB <> UART converter/adapter.



Which part of the module exactly is getting hot? And how hot? Can you still touch it?

The fingerprint scanner itself have on-board optical sensor and 32-bit CPU (GT-2). I tested the tempreture while operation is upto 69 deg celcius (MAX) raised in just 8-10 mins. I think i have to check the output current from pl2303 because operating current for GT-511C3 is 150mA. May PL2303 delivering more than that, so its getting hot.

Its just my assumption. Sorry i dont have a good knowledge of electronics.

 

[Harald Kapp]

I think i have to check the output current from pl2303 because operating current for GT-511C3 is 150mA. May PL2303 delivering more than that, so its getting hot.

Good idea to check the current consumption. While at it, also check for correct voltage.

However, the pl2303 module will not push more current into the scanner. The scanner will draw as much current as it requires, not more, not less. It is important that the operating voltage is correct and that the voltage source (PL2302 module) is able to deliver the current drawn by the scanner.

I tested the tempreture while operation is upto 69 deg celcius (MAX) raised in just 8-10 mins.

Is that the temperature of the CPU? An overtemperature of 45 ° (70 ° measured - 25 ° assumed ambient temp.) may not be a reason for concern when operating the sensor at room temperature.
But: The sensor module is specified for operation at up to 60 °C. This means the CPU will heat up to ~105 ° measured at the case. The internal chip will be even hotter (junction temperature). This may put too much stress on the CPU. Lacking more data nothing specific can be said.

 

[suyog]

Good idea to check the current consumption. While at it, also check for correct voltage.

However, the pl2303 module will not push more current into the scanner. The scanner will draw as much current as it requires, not more, not less. It is important that the operating voltage is correct and that the voltage source (PL2302 module) is able to deliver the current drawn by the scanner.


Is that the temperature of the CPU? An overtemperature of 45 ° (70 ° measured - 25 ° assumed ambient temp.) may not be a reason for concern when operating the sensor at room temperature.
But: The sensor module is specified for operation at up to 60 °C. This means the CPU will heat up to ~105 ° measured at the case. The internal chip will be even hotter (junction temperature). This may put too much stress on the CPU. Lacking more data nothing specific can be said.

Finally i got it why this happens. I integrates a resistor of 1k on rx pin from converter to fingerprint module. so the current flow resisted some how and overload on mcu has been stopped.