This project introduces CamMan-GS, another variant of the popular CamMan family of camera controller projects. As with the other CamMan designs, the main brains are from an 8-pin microcontroller.
The camera that is used in the project is the tiny Mustek GSmart Mini-2 or Mini-3. If you are not using the Mustek camera then check out the other RC-CAM CamMan projects to see what other cameras are supported.
The basic modifications center around a simple circuit that uses a microcontroller to decode the R/C "servo" signal, as well as manage the camera interface. In the case of the Mustek GSmart modification, only three parts are needed; an 8-Pin IC, capacitor, and resistor.
But as simple as that sounds, this is NOT a project for an inexperienced electronic tech. Advanced soldering skills are needed due to the fine pitched soldering that is required (most digital cameras are tiny!). If you are not up to the job then please consider the old standby solution -- glue an R/C servo to the camera and have it push the shutter button. This old trick has been used for decades and works well.
But, you will soon see that there is a higher tech method:
PIC Chip: A Camera Man's Best Friend
CamMan is based on a tiny 8-Pin chip. It is actually a MicroChip Technologies PIC12C508 microcontroller that uses custom firmware that you can download at no-charge. The PIC decodes the R/C signal for shutter activation and (optionally) manages the power up state of the camera.
Even though a microcontroller is used, cost is very low. You can build the CamMan circuit for about $10. Total parts count is very low the assembled circuit weighs just a few grams.
There are eight pins on the CamMan PIC chip. They exist as one of three kinds of signals: Power, Digital Input, or Digital Output.
The digital inputs are level sensitive and are said to be logic High when the voltage is > 2.0VDC and logic Low when they are less than 0.5V. Typical designs will use the VCC voltage (pin 1) for a logic highs and GND voltage (pin 8) for lows. The output sink current is 20mA (plenty for our application).
Let's take a quick tour of the various signals on the PIC chip:
Your exact PIC choices
have some flexibility. You can use a PIC12C508, PIC12C508A, PIC12C509, and
PIC12C509A. The PIC12C50x is not a "Flash" part, so you will need a traditional
PIC chip programmer to "burn"
the hex file's object code into the microcontroller. Be sure to select the
configuration fuses during chip burning as follows (these are optional settings
within your chip programmer's menus):
The PIC's Hex file is designed to automatically instruct the programming hardware to chose 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.
The PIC's circuitry is so simple that a circuit board is not needed. All the parts are mounted on the bottom of the PIC chip, using "Dead Bug" construction (just picture a dead bug lying on its back). For this project I recommend a 40 watt or less soldering iron with a temperature controlled tip.
There isn't enough space inside the Mustek camera to allow the use of an IC socket. My instructions will assume that the socket is not used.
Start by trimming the PIC's leads to about half their normal length. The skinny through-hole portion is simply clipped off. The photo on the left shows the details.
Next, solder C1 and R1 directly to the PIC. At this point one end of R1 is NOT connected (it will go to your servo cable). If you don't need the wake up feature then jump pin 5 to pin 1.
Assembly of the basic
PIC circuit is now complete. All that remains is to add it to your camera.
As it turns out, the tough work is about to begin.
Micro Surgery: Wiring the Camera
Let's get down to the business of wiring the GSmart Camera to the CamMan PIC. Both the Mini-2 and Mini-3 camera models follow the same instructions. All of the camera connections use 30 AWG Kynar (wire wrap) or enamel insulated magnet wire. If you use heavier wire then you will invite shorts on the camera's circuit board and will probably have trouble reinstalling the camera case.
To open the camera case you will need to peel off the serial number label. Under it is a small screw. Once removed, the case pops apart with very little effort.
The chart below shows the basic wire connections. The "Photo ID" refers to the wire references shown in the two photos found a couple paragraphs down. Be sure to review the schematics to verify you are wiring things correctly.
Use 30AWG wire and cut each to about 6" long, then solder them to the PIC IC. They will be trimmed after the PIC is installed inside the camera. Do not connect anything to PIC pins 6 and 7 at this time. They can be grounded if you need to use their special features, but that decision will come later.
Once you have the wires soldered to the PIC, install the 4.7K resistor on pin 4. Now use a small amount of CA adhesive and mount the PIC IC to the top of the controller chip in the camera.
The front side installation looks like the photo below. Solder the servo cable as shown (servo ground to point "C", servo signal to the 4.7K resistor, and the servo positive is unused (insulate it):
Double check your work. Simple mistakes can destroy the camera, R/C gear, and may generally ruin your day.
File a grove in the case to allow the servo cable to pass through. The best place is just above the USB connector, but you can pick your preferred spot to suit your needs. Reinstall the various camera pieces and covers. You are done!
Set Up and Operation:
I will assume that you will be sharing your throttle channel with CamMan. Connect the camera to the R/C receiver's throttle channel and to the servo or ESC (electronic speed control).
Turn on the R/C transmitter and apply receiver power. Turn on the camera.
First you must "Arm" the system. Move the throttle stick to full low stick then give it full up stick (do not cheat -- use FULL deflection on both extremes). CamMan is now armed. The arming procedure only needs to be done after you apply power to the camera.
You are now ready to shoot photos! If you reduce throttle to below 1/4 stick you should hear the camera beep as it stores a photo. To take another photo you must go above 3/4 stick, then back down again. Practice a bit -- you will quickly see how it works.
If the camera does not take photos then you may have a wiring problem, your stick's trim lever is too offset, or an insufficient ATV mix setting in your R/C transmitter. First you should check your wiring. If it looks good, and the stick's trim lever is centered, then you will need to increase your ATV mix settings (if available) so that they are at 100% or higher. If you are using another channel besides throttle, be sure that its Dual Rates mix is disabled.
If you are using a spare R/C channel (the gear channel works well) then the operation is nearly the same. To perform the initial system arming just flick the channel's toggle switch down then up. From then on you have switch controlled access to shooting photos. If the switch operation is backwards then either use your transmitter's channel reversing feature or ground PIC pin 7 (Reverse option).
Camera mounting is up to you. Here is how mine is installed on my electric park flyer:
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 software bugs then please report them to me. I can only make corrections if I can replicate the bugs, so please give me enough details to allow me to witness the trouble.
I would enjoy hearing from anyone that uses the CamMan system. Please send me an email if you build it.