openrcforums

Hello
Had a good summer flying my McPX with 9x. thanks a lot. Working on building a small rc car to play with arduino/various sensors I bought this spring so wanted to use the stock 9x module. Oops removed the antenna. So while drilling hole in stock RF Module for antenna, thought I'd share pics of my mod.

Nothing special here, used a 3.3 reg from hobbyking. removed it from it's shrink tubing to re arrange the components to fit inside the case. Mounted my USBASP programmer internally, installed USB port where the antenna was orignally located. Used some polymorph from sparkfun to 'putty' up the hole. really ought to sand that with some finer paper. There is a problem with the antenna out the rear. The closeness to the metal handle is a small thing, ( for me ), but the fact that I cant lay the TX on its back without pressing weight on the antenna is troublesome.

rperkins wrote:The closeness to the metal handle is a small thing, ( for me ), but the fact that I cant lay the TX on its back without pressing weight on the antenna is troublesome.

You need one of these

viewtopic.php?f=48&t=1454

It helps to have that "ledge" to rest it on that's built into the shirt. Where's the coffee cup holder?
My club won't allow a beer holder.


ShowMaster
Sent from my iPod touch using Tapatalk

Hmmmm beer Last night was red wine with rum

More photos of my mods are here.
Not big on social networking but it is nice to have all my cell phone photos automagically uploaded via google plus. This is first time ever tried this, so if you cant see the pics and want to, just post here.

Shows my internal usbasp with micro usb connector in original antenna location. Also shows the lcd backlight mod utilizing a pot to adjust brightness.

ps . I'll never be a craftsman -- just functional

Interesting, so you used a 3.3V buck converter from HK to power the RF module? I see you have a torodial inductor on the (battery?) +/- wires and added a capacitor (on the regulator output?). Were these your own additions or did the inductor and capacitor come from the HK regulator?

I was always afeared of using switching regulators in the 9x because of EMI/noise concerns, especially with the RF module, but I see you powered the RF module directly with one! It seems I was worrying about nothing...

PS: craftsman or not, you gots some skills! I dig on the IR driver you made for the coaxial toy too. Keep up the good work.

Thanks. Yes it was a 3.3v reg from HK. I never even thought to check what kind of regulator. Never had a problem with range but that's probably due to the small size of the MCPx and my limited flying skill. Yes all the components for the reg came with it. Now that I think about it I may have switched out one cap as it got damaged or diidnt fit. I just cut off the shrink wrap and repositioned the components to fit the rf module.

I'm gonna get back on the IR module. currently gearing up to offer usbasp programmers with adapters. The 9xr should drive a need for these with the relevant adapter. Watch my sig for the launch. Never setup a shopping cart before, so it's taking awhile. I'm heading towards using usbasp modules as the IR module. Remove the connector at either end and it will fit. Cant beat the price. Add transistor to drive IR led. Was stuck on moving the code to 12mhz crystal, which is really only necessary for usb communications. Also the timers are configured differently when going from a 328 to an m8.

It's hard to tell for sure, spring is just around the corner. Anyway that's the plan. Thanks for following along

Cool, thanks for update.

For IR module, if I understand correctly you plan to repurpose a USBASP programmer, reflash/change the firmware, add a transistor to drive the LED, connect transistor base to one of the ATmega8 outputs and connect a micro input to the PPM signal from the 9X or 9XR? The USBASP will act like a transceiver and your firmware will translate the PPM signals into the data packet the S107G can understand? Neat idea. Best of luck on your endeavor!

Yes thats right. And use the 3.3 vreg on the usbasp to drop the rf module voltage from Vbat to something the AVR can use. I did order some 5v reg's in the form factor, might switch them out. The issue is to drive the IR Led array at what voltage 3.3v, 5v, or Vbat. The Vbat is dependant on how the TX is powered, right ? Again, lot's of thinking and a little action. I dont mind working for a living but, darn, it takes up so much time

re: job, haha, I hear ya! This forum is so distracting!

Yes, Vbat is dependent on many factors (battery state of charge, current draw, battery temperature, battery chemistry/config, etc). I guess it depends on what type of IR LEDs. I'm sure 3.3V, 5V or even higher could be made to work, but regardless of LED type, they like to be driven by a constant current. Maybe you'll consider a simple LM317 as a constant current source (see LM317 datasheet for example). Then regardless of Vbatt (within reason) the current thru the LEDs will remain the same for consistent brightness. Use this as LED power source and switch the output thru a transistor or FET - just an idea....