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The PIC's Hex file is designed to automatically set the programming hardware to these values. However, it is always a good idea to check them for accuracy. By the way, after you program the PIC your programmer will report a failure if you attempt to verify the PIC again. Do not be alarmed -- everything is OK. Just ignore the "failure." Whatever you do, do NOT program the chip twice!
If you have trouble
burning the PIC, then please check your programmer. Whatever the fault, it
is not a RC-CAM hex file issue. The most common problem is that the
user has forgotten to burn the PIC's four configuration fuses, as mentioned
above. More programming information can be found starting
here.
LoMA Construction:LoMA's circuitry does not need a fancy circuit board. Instead, we are going to build it on the back of the buzzer. Not a single jumper wires is needed either. Could it get any easier?
Place the PIC across the buzzer pins as follows: Install the buzzer "+" pin between PIC pins 1 and 2. Place the buzzer "-" pin between PIC pins 5 and 6. Do not solder yet. Elevate the PIC 1/6" above the buzzer (the space will be used to route the servo cable in a future step).
Solder in place. PIC
pins 1 and 2 will be bridged, as shown in the photo on the right.
Believe it or not,
the hard part is done.
Now slide the servo cable under the PIC and pass the two power wires to the "top" of the chip. Solder the negative servo lead to Pin 8 and the positive to Pin 1. The servo signal goes to pin 4. It should look like the photo on the right.
Use epoxy or thick
CA adhesive to strain relief the cable. A piece of heatshrink should be used
to cover it all. Build it tough because you want it to survive a
crash.
Check it OutSimple mistakes can destroy electronic parts and may generally ruin your day, so check your work carefully. Do not install the receiver battery until you have verified that the power leads are not shorted (use an ohmmeter). If all looks good, plug LoMA into a spare channel of your receiver. If you don't have spare port then use a "Y" cable and share the throttle or gear channel. Note: LoMA works with nearly all PPM and PCM receivers. It is NOT compatible with R/C systems that utilize slow servo framerates (like some Multiplex R/C systems use). If you are using a PPM receiver, then choose a servo channel that does not have exaggerated EPA/ATV settings. (use no more than 100% mix). If you are using a PCM or 2.4GHz R/C receiver, then it must be programmed to send a servo signal that is greater than 2.05mS during failsafe mode. This requires setting the EPA/ATV to no more than 100% on the low side (LoMA fail safe off) and 150% on the high side (LoMA fail safe on). Now it's time to test your work. Just follow these simple test steps:
Power Miser ModeThere is a chance that your model will be lost for more than a day. Sometimes nightfall gets in the way or you need to return later with tree climbing equipment. Well, LoMA comes to the rescue, again, with a power saving feature. During the first hour of alarm beeping LoMA will sound off with sixteen beep strings per minute. This will consume 7mAH (milliamps per hour) from your battery. After one hour of R/C signal loss, the rate will be reduced to 6 beep strings per minute. This will consume 2.6mAH. This works out to about 80mAH per day, which is not bad at all. Once the alarm beeps are in the low power mode (after one hour) you can remotely wake up LoMA and restore the normal beep rate. Just return to the area where the model was lost, turn on your R/C transmitter for a few seconds, then turn it off. Pretty neat, don't you think?
Silence is GoldenThere is a chance that you have a model that experiences signal glitches, but still flies fine. This is typical of some low cost park eflyer receivers. In this situation, the glitch counter might end up being a nuisance rather than a blessing.
So, LoMA has another
trick up its sleeve. To disable the glitch feature's beeping, all you have
to do is disconnect the PIC's pin 2 lead and jumper it to pin 8 (short pin
2 to gnd). This will silence the glitch counter. Be sure to disconnect it
from pin 1 first or you will have smoke!
Aircraft InstallationThe alarm tone from the buzzer is somewhat directional. So be sure to mount LoMA in a location on the model that helps ensure it can be heard. If you want better audio coverage you can modify the design by using up to two (2) of the buzzers. All you have to do is solder the buzzers in parallel (pos to pos, neg to neg). Mount them facing different directions for the most effective coverage.
Design Documents:The technical details are available as file downloads. There is no charge for the information when used in a personal (hobby) project. Commercial users must obtain written approval before use. Please be aware that the information is copyright protected, so you are not authorized to republish it, distribute it, or sell it, in any form. If you wish to share it, please do so only by providing a link to the RC-CAM site. You are granted permission to post links to the web site's main page (http://www.rc-cam.com/). Please respect this simple request.
The Small Print:
All information is provided as-is. I do not offer any warranty on its suitability. That means that if you build and use this device, you will do so at your own risk. If you find documentation or software errors then please report them to me. FeedBack:
If you have
technical questions or comments about this project then please post it
on the rc-cam
project forum.
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