GPS Speed meter

[ChriX]

Hi all, just wanted to post my recently completed GPS speed meter. The idea is to have something that saves the maximum speed reached, for the main purpose of sticking to my RC car. I was quite pleased with how small I managed to make it without getting a proper PCB done so wanted to show off Thanks go to Nigel for his LCD routines and everyone who helped in my mph/kmh thread.

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It uses an EM406 receiver from www.coolcomponents.co.uk I may design a board using SMT components so that I can have a chance at getting a battery to fit too (at the moment it is powered from the RC car receiver battery).

 

[Nigel Goodwin]

Nice project! - I notice you have a MAX232 there, presumably to communicate with an external PC?. You could make it smaller by having the MAX232 external, as part of the lead to the PC.

Just a simple way to make more room, and common practice for temporary RS232 connections.

 

[ChriX]

Thanks Nigel! I used the MAX232 because the GPS module ouput talks in LVTTL, I thought the PIC would be able to handle these levels, but when testing it it couldn't. So as I had a 232 to hand i've just put the output from the GPS into the TTL side, bridged the RS232 side and connected the output of the TTL side to the PIC - not the most elegant of solutions, but it works.

Edit: A picture of it strapped to my RC (excuse the dirt!) **broken link removed**

 

[Nigel Goodwin]

Thanks Nigel! I used the MAX232 because the GPS module ouput talks in LVTTL, I thought the PIC would be able to handle these levels, but when testing it it couldn't. So as I had a 232 to hand i've just put the output from the GPS into the TTL side, bridged the RS232 side and connected the output of the TTL side to the PIC - not the most elegant of solutions, but it works.

Yes, if it works don't knock it! - but I probably wouldn't have thought of trying it that way!.

Edit: A picture of it strapped to my RC (excuse the dirt!) **broken link removed**

Nice!

BTW, how fast does it go?.

 

[eblc1388]

What an interesting use of the GPS on a RC car!

Armed with the GPS data, your RC car could in theory(with a map inside the PIC) drive itself through rugged terrain without human intervention, right?

 

[ChriX]

It could in theory, i'd have doubts about obstacle avoidance unless the obstacles were the size of small houses or something due to the accuracy of GPS.

Nigel, it went a quite dissapointing 26mph last time I checked it, but then I do have it geared for acceleration at the moment and the engine wasn't tuned very well (/excuses). Should do 40 when i've sorted it out.

 

[Nigel Goodwin]

Nigel, it went a quite dissapointing 26mph last time I checked it, but then I do have it geared for acceleration at the moment and the engine wasn't tuned very well (/excuses). Should do 40 when i've sorted it out.

I should hope so


Don't the electric powered ones do 26mph?.

 

[mat01]

Hi- just to say www.coolcomponents.co.uk now do another type of GPS receiver, the Globalsat EM408. Unlike the EM406 it has an external gold MMCX antenna connector.