Well a further update on UHF (400Mhz).
You can perhaps say that my inability to post a Youtube video correctly means that I am the perfect candidate to test this technology i.e if I can do it, you certainly can!
After a couple of hours work I have successfully "burned" the openLRS software in the TX module and the receiver and set it to the more legal 458/459Mhz frequency for the UK. The Charlie class is now working again "on the bench". (It will have to wait for another 2 weeks for a pond test.)
So I can't see any reason why those interested don't think about ordering some gear and having a go - the stuff is relatively cheap so low risk. I bought the gear too and my second receiver is now on order so that you can see I'm also sharing the risk, with no "freebies"!
My shopping list was: (I've added more detail in the latest edit following an enquiry by Davidf J)
1x #9171000147/27096 OrangeRx Open LRS 433MHz 9Ch Receiver = $19.95
1x #9171000270-0/40032 OrangeRX Open LRS 433MHz Transmitter 100mW (compatible with Futaba radio) = $19.99http://www.hobbyking.co.uk/hobbyking/store/__40032__OrangeRX_Open_LRS_433MHz_Transmitter_100mW_compatible_with_Futaba_radio_.html
1 x FTDI Basic Breakout Board 3.3v (DEV-09873) (From Sparkfun) $14.95
The last item is the RS232 "Dongle" which plugs into the 6 pins on both the TX and RX. The other end goes into the USB port on a PC. I believe this is a standard board used with Arduino devices but do get the 3.3 volt version. The 5v version can burn out the RF (radio frequency) chip in the modules.
I am now just going to give my own experiences based on the video on Tim's excellent thread on SubCommittee. Look at the whole video first.
A couple of health warnings first:
- Always leave the aerials/antennae in place on both TX and RX. They BOTH transmit and you can damage the RF chip if you don't.
- Probably best to get the 3.3 v board as above. The video covers using a 5v version but it makes the process more complicated (and risky).
The outline of the whole process is:
- On your PC install the Chrome Browser and the openLRS app. (This was a new method of installing software to me but it worked faultlessly and I am using Vista on my PC (Don't laugh!)
- You will only get the basic menu screen up at this point. (You need to plug in the devices to get the detailed menus.)
- You need to have access to the 6 pins for the Dongle and you need to identify the dtr pin of these 6. You will find dtr printed on the printed circuit boards. On the RX board you need to peel back the plastic sheathing a little to see it. On the TX module you need to take it out of its plastic box. I cut a small slot in the plastic case so I could plug the Dongle in with the module in the case. By the way dtr stands for Data Terminal Ready which perhaps gives you a clue to how long the rs232 standard has been with us!
- Flash the RX first (as per the video). Plug the Dongle in with the dtr pins coinciding. Select the button on the menu. The loading only take a few seconds and the menu tells you what is happening.
- Again as per the video, Flash the TX module. (You will find it simpler with the 3.3 volt Dongle than the video - just plug it in (dtr to dtr)
- Now you get onto the more interesting part. Setting up the devices. I got into a slight wrangle with the instructions for binding the TX and RX but just remember that you are not doing any damage and that it will all work out in the end.
- You are then presented with quite a detailed menu screen for TX setup. On the left column, type in a new frequency between 458.5 and 459.5 (UK surface users are recommended to use frequencies below 459.1) This link has useful info on UK frequencies: http://www.ukrcc.org/
-Turn Telemetry off (more on this in a moment).
On the right column you can select the number of frequency hops and how they are selected. (I chose 6 and random.)
- I didn't change anything on the RX menu.
- As a hint of how clever this system is you will see that there is a button which carries out a frequency scan. Another button displays your frequency hops.
- A bit more binding and unplugging and you should have the system working.
However, I was faced with a whole lot of jittering servos and limited response to controls. Half an hour of anguish followed before I realised that Telemetry was ON and this was creating interference. I later re-checked the video advice and I had missed that point!
My thanks again to Tim S and the SubCommittee for spotting and developing this technology.
This COULD be the answer to the equipment problems facing the r/c subs fraternity. The more openLRS equipment you all buy the more likely they are to continue manufacturing it. Continuity of supply is probaby the key issue in the ultimate success of this technology.
It would seem to have significant advantages over 40 Mhz technology and so maybe more second hand 40Mhz gear will also re-enter the market.
All good news for folks wanting to enter the r/c subs hobby!
If you use and like the software (and I do) please consider making a donation to the open source enthusiasts who created it. (You will see a PayPal button on the menu.)
P.S The next thing I need to look at is improving the aerials for use in subs at this frequency. I have just put an order for a better TX aerial into one UK based supplier of openLRS equipment:http://www.flytron.com/
I will let you know how I get on.