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Topic: Solar Mega - an Arduino MEGA shield with LCD & RTC for motor control and sensing (Read 4715 times) previous topic - next topic


Hi, I've designed a shield to go with the Arduino MEGA as part of a solar-tracker product I'm launching.
I'm interested in finding out if any other members of the Arduino community would be interested in participating in some variation of the following concept:

My company will be targeting residential solar energy customers for active solar tracking and concentrated solar power (CSP).
Using what I'm calling the SolarMega shield as a "platform", I'm in the process of developing software for a variety of tracking controllers (single-axis, dual axis, and heliostat), as well as a temperature differential controller. Part of my idea is that I can sell the software separately from the hardware, letting the customer upload a binary file to reprogram the Arduino.
What if I created a sort of Solar App Store for my Arduino SolarMega board platform (and variants for other Arduino boards besides the Mega)? Would any other developers be interested in developing applications and selling them?
It seems to me that while we all love to help each other will little code fragments, complete and tested applications are another story and hopefully this is still in keeping with the open spirit of the Arduino platform, and I'm sure lots of non-techie people would love to be able to get specialized Arduino apps for environmental sensing and control and such without having to coding.
Anyway I'm just putting it out there. Please provide some feedback so I know if it's a good idea or not!

Here's the features for v.2 of the board:

- 100 x 80 mm dimensions (same width as LCD)
- 5, 3.5mm (1/8") stereo jacks for i/o: 4 analog, 1 digital
- configurable pull-up and de-couple caps on each analog line
- cpu input pins sense plug insertion into jacks
- 16 pin header for standard 16x2 LCD module
- pwm control of LCD backlight
- 8 pin header for matrix keypad
- XBee socket
- XBee configurable for COM0 or COM3
- RJ45 ports for 2 single channel H-Bridge motor controllers
- header for a third motor controller
- 2 pulse inputs attached to interrupt capable pins (2,3) associated with motor ports
- piezo buzzer
- MCP7940 RTC with alarm (tied to pin 19, also interrupt capable)and battery backup so your arduino can wake itself up
- on board temp measurement with thermistor circuit
- pwm control of Aref with single pole R/C filter.
- 2 panel led connections
- extra I2C and serial port breakouts.

My goal was a board capable of sensing time and environment and controlling actuators, relays, and other such things needed for solar energy related process such as a single axis-solar tracker(polar or azimuth) or temperature differential control system.

I've attached a picture of the first version of the board. The guys at iteadStudio made the first pcb's for me, which incorporated a simple discrete component based single H-bridge circuit using TIP-12x Darlingtons. I quickly learned how it can short out on the USB connector, felt stupid, and decided to move the motor driver off board. The new version will have pin headers as well as standard RJ-45 jacks for motor driver connections.
I also incorporated a LM75 temperature sensor into the first version, but still haven't gotten it work. Since the RTC is also on the same I2C bus and it works, I'm not sure what's up. I decided to toss the LM75 and put a thermistor on the board instead for version 2.

I've got a few extra prototype boards I'm willing to sell (can you sense the attachment?) that have the H-bridge circuit. Like I said about the LM75, I'm not sure if that works, but everything else checks out. I'll have my new website ready this weekend to handle transactions with PayPal and post a link for that. Send me a message now though if you think you are interested.

Thanks for reading, and I appreciate any feedback.


Assuming that this unit is going to be outside, those 3.5 mm sockets will probably corrode and allow ingress of moisture.
I would review all your external connections to ensure that cables connect inside the box (terminal strips?)after coming through a watertight gland (or grommet) or go down the expensive path of using IP rated connectors.


It seems like all the fancy waterproof connectors cost as much for a working male/female pair as an Arduino, or more, so I decided to go with a sealed enclosure with room for connections and waterproof fittings. The only way that seemed practical in the end, and that allowed me to have 5 A/D fully bucked IO ports was the 3.5mm jacks, but I knew they had to be protected since any type of normal jack that plugs are commonly available for could let moisture get to the electronics.

Here's a picture of the controller in it's enclosure. Some may recognize it as a polycarbonate waterproof box for kayaking, etc. made by Outdoor Products. The membrane keypad overlay is designed for exposure and allows user control without opening the case. Double latches and a gasketed seal keep the door water tight, and I drill out for a watertight conduit fitting. I use 3/4" near the control unit, and then switch to 1/2" for the branch lines (motor, power, sensor, etc.). There's enough room in the box to make all necessary connections, and a packet of silica gel prevents condensation. I like using neoprene rubber stoppers for grommets in the end of the conduit body where any final connections are made before going out into the weather.  The stoppers get drilled out appropriately and then the wire is sealed with silicone. Flex conduit and regular pvc conduit are so cheap, it seems like a no brainer to protect as much of everything as possible, and it makes it look nice too.
I'm waiting right now to get my official franchise license from the state so I can open my webstore at HomeCSP.com.

It may not walk or talk, but a digital solar tracker is a type of robot, moving and responding to it's environment according to time and conditions. The trick in implementation is to achieve industrial-like quality without a huge budge, making a robot that lives outside quite a design challenge, but it feels like I've got most of the serious issues addressed (hopefully!)


to illuminate my room I'm trying to make a heliostat with mirrors but the software is the problem, I'm not interested in buying the hardware only a software license, is this possible? If yes, do you accept paypal?  :~


HI emdee,
thank you very much for the reply, I have relays to control the motors but am currently working on a simple h-bridge.
I have the following electronics and mount:
ARduino Duemilanove ATMEGA328P
ARduino Mega ATMEGA1280
Real Time Clock Module - RTC DS1307
Compass Module Arduino - HMC6352
ARduino  LCD Keypad Shield
Linear Actuator with reed-switch---------Altitude
Worm Gear Box  Motor with reed-switch---------Azimuth
Alt-Az Mount   http://s14.directupload.net/file/d/2885/meqygf3a_jpg.htm
I think is a very good idea if you create your sort of Solar App Store for your Arduino SolarMega board platform because for example I try to be friendly to the environment and it seems more convenient if you sell the software instead of hardware (heavy to send), unfortunately I canĀ“t  coding and  i agree with the open spirit of the Arduino platform.
I appreciate any help in advance, ( excuse my english!!!  smiley-red)


hello this is hager
i am interesting in your hardware and software could you send more details about them and the way to pay, also could you tell me when the last time you tested the system ?

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