SparkFun Forums

[AJ]

Hi JoeMaya,

sorry for the late reply i dont often check the forum
from what i can gather your levels are not correct, your must use a TTL - 232 convetor before feeding to the Prolific device a MAX232 should suffice, also make sure the power enabled line is connected
and you shouldnt need to ground the prolific

HTH

[chancy]

Hi,
Does anyone know if the UART on the fingerprint scanner is 5V tolerant or if it is powered at 3.3V?
(I'm trying to connect it via RS232, but the chip I have is 5V. The data sheet of the scanner says the UART is 3.3V)

Thanks!

[Charls_81]

Hello,

I have just started experimenting with my fingerprint scanner. The test software you guys sent me seams to be talking to the scanner and the scanner is talking back however when you swipe your finger over the sensor it has no effect. (even when the software is telling you to swipe your finger).

The error message is:
'Time out£j'
Have any of you come across this problem or do you know what the problem maybe?

Thanks

Charlotte

[marin8703]

Hi everyone. Has anyone been able to communicate with this module using a microcontroller. Im trying to do that using a PIC and am having a hard time, not getting responses. Do I still need to use a level converting chip (like MAX232) if im using a micro controller instead of a PC. The exact PIC im working with is the PIC18f2550, it has a built in USART module.

I was already provided the demo software and everythjing worked great, i think i understand pretty well the command sequence but I am having a hard time getting it to work with a micro controller.

Can someone help out? Thanks

[Charls_81]

Hi,

I posted a question n Friday however after playing with the fingerprint scanner and test software this morning I have realised that I need to press upImage after swiping my finger, by doing this I do not get an error message. I have managed to save 2 fingerprints and my usercount is 2, how do I now get it to compare fgingerprints to tell me if there is a match?

Any thoughts / ideas would be helpful.

Many thanks

Charlotte

[marin8703]

Hi,

I posted a question n Friday however after playing with the fingerprint scanner and test software this morning I have realised that I need to press upImage after swiping my finger, by doing this I do not get an error message. I have managed to save 2 fingerprints and my usercount is 2, how do I now get it to compare fgingerprints to tell me if there is a match?

Any thoughts / ideas would be helpful.

Many thanks

Charlotte

If you want to check if any of the stored fingerprints match the finger you will scan then you press the "Match (1:N)" button, if a succesful match is found among any of the stored fingerprints, the ID matching the scan will be shown to the right of the button.

If you want to check if a particular stored fingerprint matches the finger you will scan, then to the right of "Match (1:1)" button, enter the fingerprint ID, then click the button "Match (1:1)" and it will tell you if the fingerprint stored in that ID location is the same as the one you just scanned.

Hopefully that helps

Has anyone gotten this to work with a PIC or any type of a microcontroller? Thanks.

[daipv]

can somebody tell me command search & compare format(matching 1:1,1:N)?,please
thanks

[chancy]

I'm trying to get this to work with a microcontroller as well. It works perfectly with the test software.

marin8703, if your ursart is 3.3V, you should be fine to connect it directly to that. Mine wasn't, so I had to connect it to an RS232 level converter chip.. i used the MAX3232.


To send the command to the scanner, is it ok if i send the packet in 'clumps'? Like first the header then the device address then type of packet etc? This is what I did, but I don't get a response from the scanner.

Anyone have any advice for those of us hooking it up to a microcontroller- like how to send and receive the commands?


Thanks!




edit: one more thing, is it ok that I have the powerEn connected to Vcc? It worked fine when connected to the computer, but just wondering if it'd affect it when connected to the microcontroller. Thanks!

[AJ]

Hi Guys and Girls,

See no reason why it wouldnt work just as well with a microcontroller, be warned getting those timings correct may be hard work, i would get it working well with a windows application first then when happy port it to asm or c or pic basic etc

As for communicating with it, well most pics have a uart onboard and is very simple to use from what i remember

Chancy, you will need to send the complete packet each time, bear in mind that the packet contains the packet lengh, checksum etc so needs to be complete each time it is sent

[JoeMaya]

Thanks AJ, I have got my fingerprint to talk to my pc now but i have a problem trying to pass bytes in c to my fingerprint module.
Please, can anyone help with the representation of bytes in c in a manner that the fingerprint would understand. Eg. Like passing the delete command "EF 01 FF FF FF FF 01 00 03 0D 00 11" to the fingerprint module in c code. If there is anything extra that needs to be added to make the code work, please let me know.
Thank you

[AJ]

Hi Joe,

I have never used C to write anything specific, VB uses the mscomm component, which is pretty flawless when it comes to serial comms, prehaps you could write a quick class file (dll) with vb and reference it from your C app?

[chancy]

Thanks AJ.

I'm having the same trouble as you JoeMaya, passing the command in separate parts was the only way I could think of. I'm not sure how to send the whole command at once because its too big to store in a unsigned int.. if I store it in a string, wouldn't that not work since the command needs to be in hex and not ascii?

Here's one thing I don't get.. the module needs 8 bit data, 1 start, 1 stop and no parity (my usart is configured the same way)... but its okay if I send it the whole command at once? won't it get truncated?

Please advise!

[AJ]

Sorry i may have confused you, i mean send byte by byte but dont leave any abnormal gaps inbetween bytes to ensure no timeouts

[JoeMaya]

Am able to pass the command byte by byte to the fingerprint scanner but i have a problem representing the bye 0x00 when my microcontroller passes the bytes over the serial port to which my fingerprint is connected to. It recognizes the 0x00 packet as a null and not a a 00 byte. Assuming i was sending the delete command which is EF 01 FF FF FF FF 01 00 03 0D 00 01, the 00 byte is read as null as so distorts the rest of the bytes. I therefore read EF 01 FF FF FF FF 01 0A ...... instead of the 00. the distortion starts right where the first 0x00 byte appears.
Can anyone please help with the representation of the zero byte?
Thanks.

[chancy]

Thanks AJ~
Good news. I finally successfully sent the fingerprint scanner the delete command. For some reason though I only get back an 'a' from the scanner... I don't get the whole response packet. Does that sound normal?

Now I'm trying to match a fingerprint; can anyone help with what commands I need to send to be able to do this?

I was sending the command 'PS_GetImage' which I don't think does anything on its own- I get a response from the module- the light blinks but it doesn't send back any hex response.

Joemaya: I'm not sure why it doesn't recognize 0x00.. that is what I put exactly. FYI, I saved my data into a u_int array (so each field contains one byte of the command) and looped through the array to send each byte.

TIA!

Edit: Does anyone have a free comm port sniffer they can suggest using? Thanks!