Hi! We see you’re using an ad-blocker. We’re fine with that and won’t stop you visiting the site.
But as we’re losing ad-revenue from this then why not make a donation towards website running costs?. Or you could disable your ad-blocker for this site. We think you’ll find our adverts are not overbearing!
Posted: Sun Mar 25, 2007 9:08 pm Post subject: GPSlim236 troubles
Hey all i am new to these forums and to the world of gps. I just got a GPSlim236 receiver but i am having troubles with it. For some reason it is picky when it wants to work. I just cant think its defective cause when it is working it works top notch. i get full signal and no drops. When i turn it on sometimes it will fix almost immediately. Other times it will just sit there with the blue tooth light flashing and in search mode. So i took my battery out and left it over night. i turned it on first thing today and it locked on. i shut it off adn turned it back on in about 10 seconds. then i would not lock on. I even kept it in the exact same place. Then i did the same thing shut it off and turn it back on and it fixed. so since it fixed i just left it on. my original goal was to let the battery run out then take it our for a few days and try to reset the memory. I was also wondering about sometimes when i shut it off and turn it back on only the blue tooth light flashes and it looks like teh signal light is just faintly on. Is it jsut hte device being pickey or is mine defective. i hope not cause i heard warranty stuff takes months to get anything back.
Joined: Feb 23, 2005 Posts: 376 Location: Catford, London, UK
Posted: Tue Mar 27, 2007 9:35 pm Post subject:
Hi,
It doesn't sound particularly happy, but it's probably too soon to consider getting an RMA. It may take a few days to get a full set of ephemeris data stored (especially if you keep resetting it).
Firstly, when it has difficulties, does it have a good view of much of the sky (i.e. not indoors or behind an athermic windscreen, etc.)? I confirm that SiRF3 receivers can have difficulties (perhaps worse than some other receivers) acquiring, once they are moving.
You shouldn't really need to keep "resetting" the GPS, but if you want to, you can force a warm or cold start using PPC software such as "GPS Viewer" rather than removing the battery. My Holux did once tell me that I was travelling at 12mph in the middle of the English Channel, when I was actually sitting in a barn in Surrey, which did take a Cold Start to cure. Software like GPS Viewer or VisualGPSce, etc., will also give you a good idea of the received satellite signal strengths, and which are being used to make the fix (or failing to).
Joined: 11/07/2002 14:36:40 Posts: 23848 Location: Hampshire, UK
Posted: Wed Mar 28, 2007 4:15 pm Post subject:
I ask because if you'd purchased from an authorised retailer you would be able to return it to them. Unless the eBay seller is willing to handle warranty issues then you'll have problems _________________ Darren Griffin
Yeah they say that they will refund or exchange defective or unsatisfied products. here is some more info. When i turn it on and everything seems all set, the blue tooth is flash and the orange light is solid, ill let it sit and try to get a fix. after about three minutes of no fix i tried to pair it with my computer useing the included gps veiwer software. When i hit the search button it does not pick up my gps. the only time it picks it up is when i turn it on and it has a fix. Since i use this receiver with my psp i was able to find a program that displays the NMEA sentences that the gps receiver puts out. Here are the results.
GPS on, bluetooth flashing, Orange light solid but not fixxing. Gives scrambled text.
GPS on, bluetooth flashing, Orange light Flashing. Gives good NMEA code.
GPS on, Bluetooth flashing, orange light not on. Nothing
Is it the unit or are these things not made to be turned off then on again right away.
oh and jsut an update i left my battery out for 2 days fully charged. i turned it on this morning and it fix right away inside my house. I was able to drive to school with no problems until i got in a parking structer where as expected i lost my signal. while it was working i checked and the NMEA data was perfect. When i leave at 7 i am going to check to see if i have the same results.
yes thanks to the great mind of densika at DCemu.co.uk us psp homebrew users have been able to use the psp as a gps device. he wrote a program called map this which uses maps download from google. By modding a usb mini b cable and a psp serial port controller you can connect the two. Its really great. but again my biggest concern is are peeple experincing the same things i am. could it be that the gps is not made to be shut off and turned out right a way.
Joined: Feb 23, 2005 Posts: 376 Location: Catford, London, UK
Posted: Thu Mar 29, 2007 4:09 am Post subject:
Hi,
Switching off briefly and then on again, is very unlikely to damage the GPS permanently, but it might cause it to malfunction temporarily. If its power-up reset circuit doesn't restore quickly, then the microcontroller may not initialise correctly, giving unpredictable behaviour.
It is attention to detail like this that may differentiate a "bomb proof" design from a "temperamental" one, and it seems the Holux 236 may fall into the latter category. For example, it's been suggested that the firmware does not filter out "dangerous" (high) baud rate selection commands that are incompatible with Bluetooth, causing it to become unresponsive. Also, I certainly have an issue with specific errors (not corruption) in some of the NMEA data strings which it transmits, that I'll probably raise in the Advanced forum, in due course.
But as far as jpc1284 is concerned, why don't you just avoid switching it off for brief periods, at least until you've checked whether or not it works correctly in all other respects? BTW, the Blue(tooth) LED should always flash, but at a slower rate when BT is connected.
yes when i go to connect by blue to the ligth does flash signifacantly slower. but when i am seeing the bad nmea sentences sirf demo and gps veiwer dont even show teh gps when i scan for it.
Joined: Jan 14, 2005 Posts: 19638 Location: Blackpool , Lancs
Posted: Thu Mar 29, 2007 2:53 pm Post subject:
Double check your lead and soldering, make sure there are no shorts screen to core or core to core, interesting project though using the PSP.
Is the problem only observed on the PSP or other hardware? - Mike
yes and no. On the psp when you get the corrupted NMEA sentences there is something wrong with either the cable or the gps. But even if the gps can't fix it should still send proper NMEA sentences. But if my cable is bad it should not affect the gps in sat acquisition either. I have turned it on and let it sit out side with wide open sky. no fix for over 2 hours. i check the NMEA and they are all corrupt. when i try to pair with my pc via blue tooth it cannot find the gps. But on the rare occasion it does get a fix i checked the NMEA with the psp and all was good. I was even able to connect to the gpsveiwer on my pc via blue tooth. I have yet to have the unit send good sentences and not get a fix or pair with the PC. The only time i cant get a fix is when the sentences are corrupt which i cant even pair it with a pc. I think it is obvious that it is defective but i really wanna trouble shoot this for future reference in case other people have the same problem. http://www.dcemu.co.uk/vbulletin/forumdisplay.php?f=169
here is a link for all the information on using a gps with a psp.
Joined: Feb 23, 2005 Posts: 376 Location: Catford, London, UK
Posted: Thu Mar 29, 2007 9:33 pm Post subject:
Hi,
The device certainly sounds faulty, for example if a master clock (oscillator) is running at the wrong frequency it could corrupt the NMEA sentences and prevent satellite acquisition. You need a 'scope, or something, to identify what is wrong with the NMEA data (e.g wrong signal levels or wrong baud rate, etc.).
You have technically invalidated any warranty by connecting an "unapproved" cable to the device, which could have damaged the gps, for example by ElectroStatic Discharge. You really should have checked that the device worked properly (i.e. with the LEDs and BT link to PC) before connecting any home-brewed kit.
This would be the first case of that ever happening. Or at least the first one ever mentioned in a forum. But the cable i used was bought off ebay not to mention anytime you use the GPSlim as a mouse device it has the same wire connection. BUt again thanks for all your help hopefully this company will give me an rma number i am asking fora refund from them so i can get a 240 anyways.
Posted: Today Post subject: Pocket GPS Advertising
We see you’re using an ad-blocker. We’re fine with that and won’t stop you visiting the site.
Have you considered making a donation towards website running costs?. Or you could disable your ad-blocker for this site. We think you’ll find our adverts are not overbearing!
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum
Or you could disable your ad-blocker for this site. We think you’ll find our adverts are not overbearing!
Hi! We see you’re using an ad-blocker. We’re fine with that and won’t stop you visiting the site.
But as we’re losing ad-revenue from this then why not make a donation towards website running costs?. Or you could disable your ad-blocker for this site. We think you’ll find our adverts are not overbearing!
Forum FAQ
Search
Usergroups
Profile
Log in for private messages
Log in
8) 
