Custom H-Bridge (tha MOSFET mod)
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maximan
- bitThug
- Posts: 90
- Joined: Mon Jun 16, 2003 7:17 pm
- Location: toys r us exchanging ms pros boards for thunder charger boards
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ph2t
- bitPimp
- Posts: 1979
- Joined: Tue Mar 25, 2003 6:33 am
- Location: taco city
It's all about space max, and I don't have a hell of a lot. You need extra components to be able to turn on the FETs if you don't remove the original transistors from the RX PCB. Doing this and steering means the board would be bigger. More testing continues........
At the moment I wanna get:
1) Easy install, solder only 4 wires to the RX pcb.
2) High performance H-Bridge
3) Regulated 5V voltage source for LED headlights
Later as development continues:
4) Neutral brake circuit, for 3.8 motors and higher.
5) FET based steering.
ph2t.
At the moment I wanna get:
1) Easy install, solder only 4 wires to the RX pcb.
2) High performance H-Bridge
3) Regulated 5V voltage source for LED headlights
Later as development continues:
4) Neutral brake circuit, for 3.8 motors and higher.
5) FET based steering.
ph2t.
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ph2t
- bitPimp
- Posts: 1979
- Joined: Tue Mar 25, 2003 6:33 am
- Location: taco city
Making progress pimps. Making the pcb is the current hurdle. I've been experimenting with using overlays printed on transparent overhead sheets.
Like this:
This overlay is put on top of a uncut piece of copper sheet pcb that has been treated with a resistive coat. This is wedged between glass to ensure there is no space between the overlay and copper to ensure a sharp transfer.
This jig is then exposed under a UV lamp for about 30 minutes...
This changes the chemical composition of the expose resist that makes all the pretty copper tracks appear during etching.
Got some more pics to upload but I've been having troubles getting this process right!
more to come.......
ph2t.
Like this:
This overlay is put on top of a uncut piece of copper sheet pcb that has been treated with a resistive coat. This is wedged between glass to ensure there is no space between the overlay and copper to ensure a sharp transfer.
This jig is then exposed under a UV lamp for about 30 minutes...
This changes the chemical composition of the expose resist that makes all the pretty copper tracks appear during etching.
Got some more pics to upload but I've been having troubles getting this process right!
more to come.......
ph2t.
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ph2t
- bitPimp
- Posts: 1979
- Joined: Tue Mar 25, 2003 6:33 am
- Location: taco city
Testing stage by stage at the moment, trashed way to many prototypes getting this @#$%^ right!
A handy utility to come out of having a 5V source on the PCB to drive the FETs is that you can run headlights off it. The blue ones pictured below are bloody nuts and need a fair bit of voltage (3.6V) to turn on......
ph2t.
A handy utility to come out of having a 5V source on the PCB to drive the FETs is that you can run headlights off it. The blue ones pictured below are bloody nuts and need a fair bit of voltage (3.6V) to turn on......
ph2t.
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payaso
- bitPimp
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- Contact:
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ph2t
- bitPimp
- Posts: 1979
- Joined: Tue Mar 25, 2003 6:33 am
- Location: taco city
With a 50sec charge at 1A gave me about 10 minutes with just the LEDs running. Measuring with a multimeter has shown that the current drain is about 30mA. This is just over 10% of the total drain the car pulls on the battery when in motion so it's not that bad.
Also, due to the increased efficiency of the FETs I've noticed a longer runtime generally because the motor is now getting a lot more current than before, the LEDs will offset this yes, but not by much.
Anyways real world results will tell once I've finished this beast. The LEDs are just a sideline to the main project of the FET pcb.
ph2t.
Also, due to the increased efficiency of the FETs I've noticed a longer runtime generally because the motor is now getting a lot more current than before, the LEDs will offset this yes, but not by much.
Anyways real world results will tell once I've finished this beast. The LEDs are just a sideline to the main project of the FET pcb.
ph2t.
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noxorc
- bitPimp
- Posts: 2104
- Joined: Wed Feb 19, 2003 2:49 pm
head ache? I think it looks like the starting project for the next StarWars character.ph2t wrote:Testing stage by stage at the moment, trashed way to many prototypes getting this @#$%^ right!
A handy utility to come out of having a 5V source on the PCB to drive the FETs is that you can run headlights off it. The blue ones pictured below are bloody nuts and need a fair bit of voltage (3.6V) to turn on......
ph2t.
WireHead and PuddyButt.
-nox
