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Apr 17, 2012, 02:25 PM
looks like the hackmods site is down. I really want to do this with my MLP4DSM!
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Apr 17, 2012, 03:40 PM
SO I've read 80% of this thread (backwards), we really need the first post edited to have all the most important stuff together! oouf, I still didnt really find out what code to use but I seem to have the schematic stuff figured out.

My plan is to use the module from a MLP4DSM with an arduino mini 8mhz with my Wfly wft09 which uses futaba type modules. Anyone able to point me in the right direction? thanks!
Apr 18, 2012, 03:46 PM
Registered User
I am using the MLP4DSM Tx module powered by the onboard regulator,
the regulator doesn't even get warm to touch.

I think my sketch is the most recent to work with futaba (one page back).
Apr 18, 2012, 03:54 PM
ROFLCOPTER
Iron Savior's Avatar
I've got my transmitter working and right now, I'm powering the RF module with the 3.3v regulator on the Uno. The next challenge I'm facing is that I want to be able to reset the RF module without having to remove power from the arduino itself. I'm thinking that I would want to set up a digital output pin to somehow interrupt the ground connection at the module--but I'm not sure how to accomplish this. I don't want the voltage supplied to the RF module to change as a result of varying current loads and I also don't want to reduce the amount of current that it's allowed to draw. I'm thinking that this is a job for a transistor, but maybe I'm also crazy and/or stupid.

I've gone to enormous lengths today to try and learn this (bought and read some books, called some people, made a pilgrimage to an electronics supplier who somehow doesn't stock any transistors what-so-ever), but I think I'm missing something very fundamental here. How do I programatically power-reset the RF module without upsetting its regulated power?
Apr 19, 2012, 04:31 AM
ROFLCOPTER
Iron Savior's Avatar
Ok now I'm thinking that in both cases (Uno vs 3.3v pro mini) I should maybe use a PNP transistor since the voltage driving the load will be either lower-than (Uno) or equal-to (pro mini) the switching voltage. Is it appropriate to drive a significantly higher current (like 200 mA supplied by a separate regulator) at the same or lesser voltage than the base via PNP transistor? Should I be looking at a FET instead? I'm so confused--at least my code is in good shape ^_^.
Apr 19, 2012, 06:15 AM
Registered User
why would one want to reset the rf module without resetting the arduino?
Apr 19, 2012, 06:29 AM
ROFLCOPTER
Iron Savior's Avatar
Quote:
Originally Posted by wolfmanO
why would one want to reset the rf module without resetting the arduino?
The bind function is only available if you use it directly after the RF module powers on. It won't enter bind mode if you have already sent out normal control frames. I'm writing a software library that will support multiple concurrent receivers with a single RF module. Therefore, I will need the arduino's program state to remain intact while resetting the RF module in order to enter bind mode arbitrarily.

I suppose that it might also just have a switch that prevents normal operation until I'm done binding--although I've not tested binding multiple receivers without powering off the RF module. If it is the case that I cannot, then I can still have N bind switches or a multi-position switch that can be keyed during power-on to indicate which receiver to bind.

Even so, I would still like a way to reset the module programatically.
Apr 19, 2012, 08:45 AM
Registered User
Iron Savior,
First, you do not want to control the RF module by switching the ground on and off. That's going to cause all kinds of problems with current flowing in and out of the TTL serial input pin on the module as long as V+ is still on. Using a transistor to control the V+ will induce a voltage drop. The RF module may still work but the CYRF6936 will output reduced RF power. You could use a separate 3.3V regulator with a remote shutdown pin to control the RF module. These are commonly available and can be controlled from an IO pin on the Arduino.. You could also use one of these, which I've used in the past. They work very well, too.

www.fairchildsemi.com/ds/FD/FDC6326L.pdf
Apr 19, 2012, 08:47 AM
Team WarpSquad
Daryoon's Avatar
Quote:
Originally Posted by forsakenrider
looks like the hackmods site is down. I really want to do this with my MLP4DSM!
It's back up now. Sorry about the inconvenience.

HacksMODS DSM2
Apr 19, 2012, 01:50 PM
ROFLCOPTER
Iron Savior's Avatar
Quote:
Originally Posted by hammer22
Iron Savior,
First, you do not want to control the RF module by switching the ground on and off. That's going to cause all kinds of problems with current flowing in and out of the TTL serial input pin on the module as long as V+ is still on. Using a transistor to control the V+ will induce a voltage drop. The RF module may still work but the CYRF6936 will output reduced RF power. You could use a separate 3.3V regulator with a remote shutdown pin to control the RF module. These are commonly available and can be controlled from an IO pin on the Arduino.. You could also use one of these, which I've used in the past. They work very well, too.

www.fairchildsemi.com/ds/FD/FDC6326L.pdf
Considering that the serial comm to the RF module can also be programatically halted, would it not make sense to simply do that prior to interrupting its ground connection with a transistor?

What about using a transistor to shut off power to a separate voltage regulator that powers only the RF module?
Apr 27, 2012, 12:23 AM
ROFLCOPTER
Iron Savior's Avatar
Alright, after a week of study and experimentation, I think I have designed a circuit that will allow me to shut off the power supply to the RF module. In the attached schematic, I'm using Pin-X (any digital output from the arduino) to signal a transistor that shorts the ADJ pin on the LM317 to ground, which reduces its output to the lowest voltage (1.2v). I've built and tested this circuit and it seems to work--that is it seems to work based on the feedback from the LED on the RF module itself. I haven't tested whether or not I can re-enter bind mode using this method yet. I will report my findings when I do.

I've never designed any circuits before and I would welcome comments.
Last edited by Iron Savior; Apr 27, 2012 at 12:52 AM.
May 06, 2012, 06:12 PM
Don't leave it Stock
mrfliboy's Avatar

A Little/Lot of Help needed LOL


First off thanks to all that have made this thread come alive. Great work here.

I've been working this now for aquite a few days with no success. Using Cs original post: https://www.rcgroups.com/forums/show...&postcount=237

I've had no luck at all. My changes are as follows.

5V UBEC in line after TX 9.6v power to a 3.3v reg (removed from DX4E) 5V to raw and to 3.3v reg.

No changes to code at all. Futaba 7U (shows RF signal on display) or my trusty 7C that I already use with a chainlink LRS.

I have 2 DX4E modules available and both do the same. I am able to rehook to DX4E Tx and verify working with a AR6400 brick/rx.

In bind mode I get the red 4/sec flashes and normal I get the green 1/sec flashes.

I am able to get a serial monitor screenshot but thats greek to me, no offense to any greeks LOL

Any and all hel;p greatly appreciated
Last edited by mrfliboy; May 06, 2012 at 06:48 PM.
May 07, 2012, 10:50 AM
ROFLCOPTER
Iron Savior's Avatar
Thanks for the inspiration. I've found the hardware discussion here very relevant to my own project and I'd like to offer my contribution.

I've decided to release my code. This thread seems to be centered on the idea of using non-dsm2 transmitters to control dsm2 receivers using the arduino as a PPM decoder and translator. My code could certainly help such efforts, but I'm going in a more general-purpose direction. I don't want to be a distraction/source of confusion for people working on transmitter-translator projects, so I created a thread for a more general-purpose hardware/software discussion.

If you want to read about it, take a look over here.
May 07, 2012, 04:17 PM
Quote:
Originally Posted by wolfmanO
I am using the MLP4DSM Tx module powered by the onboard regulator,
the regulator doesn't even get warm to touch.

I think my sketch is the most recent to work with futaba (one page back).
Hey, I cant figure out how to get it working 100% first off I cant figure out what pins you use for LED, and second I cant get the bind function working. It ALWAYS goes into bind mode whether I press the button or not. The bind pin should be shorted to ground for bind mode at power on and then connected to VCC through a 10k resistor for regular mode?
May 07, 2012, 09:55 PM
Ignore that! it automatically goes into bind mode if no previous successful bind was made on the last attempt! duh! soo cool! I'm so happy! this is awesome!


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