Renard-WC Wireless Controller

[Penfold]

Ernie, could your technique work easier if you pre/tin the part. What do you think?

[ErnieHorning]

The problem with pre-tinning is that these pins are very small and short. Heating them without assembling will melt the little plastic holders.

Tinning is used to burn off oxidation. I'm pretty sure that these pins are gold plated. Gold oxidizes at a very slow rate and doesn't need tinning. Tinning would also add even more solder and increase the chance of solder running down inside the connector.

[dirknerkle]

RS485 Patch for Ren-W as a Transmitter at the PC

I just updated the Wiki troubleshooting documentation on the Ren-W with a better way to make Ren-W into a transmitter directly from your PC. The technique uses only the -485 and ground lines and the Max232 chip inverts the signal and feeds it to the XBee via the zener diode.

The patch is very easy to make and has been well-tested. It works with both passive and active (powered) RS485 outputs, whether it be an RS232-RS485 converter or a USB-485 converter.

1. Cut the copper tracings in two locations shown in RED LINES in the photo.

2. Solder short jumper wires where the BLUE LINES appear in the photo.

[dirknerkle]

Idun's Ren-W Explorer

Idun came up with a great idea after studying the Ren-W's tracings, and in light of the board modification in the previous post about the RS-485 patch, it's now possible to make a Ren-W into an Explorer board and use your standard RS-232 cable to program the XBee radio. In addition, the new idea also allows using straight RS-232 with the Ren-W as a transmitter instead of requiring RS-485! Idun's idea will save the cost of having to purchase one of the XBee USB Explorer boards from Sparkfun Electronics.

Idun gets all the credit on this one!!!

The bottom line are the following connections, which make it a duplex connection to your PC:
1. Pin 4 of Ren-W's J1 connects to the TD pin (pin 3) of the DB9 connector.
2. Pin 4 of Ren-W's J2 connects to the RD pin (pin 2) of the DB9 connector.
3. Pin 1 of either the Ren-W's J1 or J2 connects to GND (pin 5) of the DB9 connector.
4. The XBee radio must be in the TX (left) side of the Ren-W and JP5 must be jumpered.

You can make your own cable to accomplish the above, or...

In keeping with the "plug-in" concept, attached is a JPG of the ExpressPCB tracing (and the PCB layout as well) of a handy circuitboard you can make if you choose to make one. All you need are two RJ45 jacks and a female DB9 connector for the RS232 cable. This sample board was only 1-1/2" x 2" in size. You MUST make the RS-485 patch to the board or this will NOT work.

How to use:
1. Plug the XBee radio into the TX (left) side of the Ren-W.
2. Attach a jumper shunt on the Ren-W's JP5.
3. Be sure the Ren-W has power.
4. Plug J1 of the Explorer into J1 of the Ren-W
5. Plug J2 of the Explorer into J2 of the Ren-W
6. Plug the board into your PC's RS232 cable
7. Use the XCTU software as normal. You may find it will take a few moments to access the XBee module, but you'll be in full duplex mode. You can read all the settings, change them, rewrite them, etc.

Way to go, Idun!!!

[ppohlman]

Hey Dirk -

I was looking at ordering the necessary part for a couple Ren-W's from mouser today and noticed that the 3.3 V regulator is on backorder and won't be in until October!!

Do you know of an acceptable replacement for that particular component?

[dirknerkle]

Wow! I did a Google search for the part and Jameco has them in stock. Digikey showed none. It's a Texas Instruments part, and the TI site shows that Avnet, Rochester Electronics have 1K of them in stock between them, so you might have to go elsewhere to get the little guys... Avnet link below -- looks like their price is only $.20 each but the minimum qty is 50.

I don't see an exact replacement from Mouser, which is surprizing. Any 3.3 regulator will work in receive mode as the board draws only about 75ma in receive mode. In transmit mode it could be upwards of 325ma.

Avnet link:
http://avnetexpress.avnet.com/store/...=UA78M33CKCSE3

[dirknerkle]

Funky Ren64/Ren-W Problem and Solution

For those of you who may experience some inconsistent activity on channels 57-64 (and quite possibly again at 121-128) when running your Ren-W at 57600 baud, it has taken the cumulative brainpower and effort of multiple individuals as well as many, many hours of experimentation and analysis to come up with solutions, of which there are many. Many thanks to tweist and Phil S. for their insight and assistance. The solutions are posted on the Ren-W Troubleshooting page in the Wiki, but the most recent one is highlighted in a nutshell below...

The main issue is related to baud rate timing: the XBee's baud rate is actually a bit faster than 57600, which is the exact rate the 16F688 pics are running on most Renard boards. This speed mismatch can create an overrun issue as the XBee is sending bytes slightly faster than Renard can gobble them up, and the result can be some erratic control of channels 57-64 or, in effect, every 8 pics.

The best solution is to set Vixen to use 2 stop bits instead of only one, and then change the PARITY setting in the XBee radios to 3-MARK PARITY. If this solves the problem for you, then you're good to go.

However, depending on the firmware version of your XBee radios, the above changes alone may still not solve the problem, especially for those whose XBee firmware is version 10CD. This version apparently has exhibited some unsolvable communication problems (not just with the Ren-W but with other XBee projects worldwide) and the fix is to upgrade the XBee's firmware to version 10E6. But performing the firmware upgrade isn't as straightforward as you might think because the 10CD firmware tends to disconnect in the midst of the firmware upgrade, which causes the upgrade to fail.

Luckily, the workaround is to first DOWNGRADE the firmware to version 10A5, reboot the XBee, then upgrade it a second time to 10E6, bypassing 10CD altogether. Afterward, you must still change the parity setting to 3-MARK PARITY.

We have been quite diligent in keeping the Ren-W information in the Wiki up-to-date as any changes are made or new problems are addressed and most of these changes appear either on the Configuration, Construction, Q&A or Troubleshooting pages.

-dave

[Jrd]

Wow, great job everyone involved! I love how this thread and the wiki keep getting updated as the Ren-W project moves forward.

[XmasInGalt]

Originally Posted by dirknerkle

Wow! I did a Google search for the part and Jameco has them in stock. Digikey showed none. It's a Texas Instruments part, and the TI site shows that Avnet, Rochester Electronics have 1K of them in stock between them, so you might have to go elsewhere to get the little guys... Avnet link below -- looks like their price is only $.20 each but the minimum qty is 50.

I don't see an exact replacement from Mouser, which is surprizing. Any 3.3 regulator will work in receive mode as the board draws only about 75ma in receive mode. In transmit mode it could be upwards of 325ma.

Avnet link:
http://avnetexpress.avnet.com/store/...=UA78M33CKCSE3

Mouser shows 1667 in stock on this regulator: 595-UA78M33CKCS. It looks like it has the same specs.

[dirknerkle]

For those who are looking for the 3.3 voltage regulator for the Ren-W (and Mouser is well out of stock), here's one from National Semiconductor, available from Avnet. They apparently have plenty in stock at about $.93 each.

It's part # LM3940IT-3.3/NOPB. Here's a direct link to the page:

http://avnetexpress.avnet.com/store/...m=LM3940IT-3.3

It's an LDO 3.3 regulator in a TO-220 case that looks like it's a direct drop-in.