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Introduction
With the introduction of the h1900 series of PDA's Hewlett Packard has brought PocketPC based PDA's in reach of many people (read: affordable). Since January 2003 I'm the proud owner of a h1910 which I bought in the USA. I selected a Hewlett Packard PDA because of the experiences of people I know with this brand. Only the h1910 fitted into my budget, so I had to do without the connectivity features like WiFi, Blue Tooth and RS232. Until recently, this was not a problem since the synchronization to my laptop using either USB of IRDA was functioning perfectly. In the meantime I became the owner of a Motorola Oncore VP (8 channel) GPS receiver which I bought for only $14,95 via the internet. This type of GPS receiver was used in American cars. The GPS receiver has a serial interface at TTL level. This is why a direct connection to my laptop was not possible. Using a provided schematic I build a RS232 interface to the GPS receiver. Using my laptop and Route66 it is well possible to plan your route using a GPS receiver. But it would be nicer to be able to use my PDA with navigation software like TomTom Navigator (using spoken instructions). Because the h1910 lacks of interface possibilities, a GPS receiver was said to be impossible to use on the h1900 series. I have searched the internet to find solutions to use to IRda port to connect the GPS receiver to my PDA but the all available serial to IRda converters needs to be initialized using software and my GPS receiver will never be able to do that. This is why I decided to design my own GPS to IRda converter. This converter would not have to be initialized and would be build for the NMEA 0183 sentences my GPS receiver (and many others) produce at 4800 baud. To be able to send IRda signals I studied the IRda protocol first. Most of the GPS receivers are able to speak NMEA 0183 next to the manufactures own implemented protocol. Officially the protocol has been defined to use RS232 at 4800 baud (4800 , No Parity, 8 bits, 1 stopbit) but many manufactures implement NMEA 0183 at higher speeds. With the this knowledge about IRDa and NMEA 0183 I have designed a low cost electronic schema. See the result here. This design has been successfully tested on the hardware I own. I'm trying to maintain a list of additional hardware/software the has been known to work with this design. Please do not hesitate to email me with any question. Be aware that this is a hobby of mine so please be patient if I do not reply soon.
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