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1  Using Arduino / Audio / Tenda TBD380/mdfly AU5121 in parallel mode on: April 14, 2013, 01:12:07 pm
Hi all,

I was hoping to control a Mdfly mp3 player AU5121 (Tenda TBD380) with an Arduino Uno board. I ordered 2 units and they both arrived in parallel mode. I've tried to read up on how to use this device with a microcontroller and it seems everyone is using it in Serial mode. Has anyone had luck using this mp3 player in parallel mode?  If parallel mode is problematic, has anyone tried to reconfigure the board? It's not clear to me how hard it would be to move the jumpers.

I am trying to build a device to make prey distress calls to lure small predators (foxes, etc.) to motion-activated cameras, partly for fun and partly for a research project. I want to be able to turn on and off the mp3 player and adjust volume and song selection with the microcontroller.

Thanks for any insight you can provide.

2  Using Arduino / Project Guidance / Re: power demand on arduino camera trap project on: October 21, 2012, 09:50:43 pm
It's not clear to me why it would be especially wasteful to use the Arduino to regulate the voltage (I'm a biologist and can barely work my TV remote, so bear with me smiley). So it would be more efficient to find a different DC-DC converter and use that--like a 12V-5V or 6V-5V? What is it about the Arduino volatage regulation that makes it inefficient compared to other methods?

3  Using Arduino / Project Guidance / Re: power demand on arduino camera trap project on: October 21, 2012, 02:52:44 pm
I just run the 12V power leads to a barrel connecter and plug to the Arduino, then power the sensor from the Arduino. Would it be more efficient to power the sensor through a separeate 12V-5V stepdown? I have some murata DC-DC converters hanging around, so I could try that.
4  Using Arduino / Project Guidance / Re: power demand on arduino camera trap project on: October 21, 2012, 12:29:54 pm
Thanks for the prompt feedback. I'm pretty sure the Arduino is hogging the power, since the sensor's listed power supply is 8mA, and I'm drawing roughly 100mA (burning through a 45ah 12V in two weeks), I think I calculated that right...

So I think I'll try the Arduino Pro Mini -- can anyone recommend between the 3.3V vs. 5V? I think the x-band sensor works with either, but I'm not sure what the functional difference would be. [,ProductName].

I read through the linked tutorial on cutting power consumption. I'm having trouble understanding what exactly it means to put the board to sleep. Is it possible to have the motion sensor actively sensing for motion, but also have the board in some sort of power saving mode?

Thanks again for the feedback, I appreciate the help.

5  Using Arduino / Project Guidance / power demand on arduino camera trap project on: October 20, 2012, 08:57:40 pm

I've been using an Arduino Uno board to run a camera trap. The input to the board is a parallax x-band motion sensor (powered via the board), and the outputs are the focus and shutter controls on my camera. I run the board on a 12V SLA battery. Everything works great, I now have two camera traps set up and I love the pictures I've gotten. The only issue that I use up a lot of power--I require a 45ah 12V to run my camera trap for ~2 weeks--hiking my camera into remote spots is a pain when I have to lug a car battery along with me.

Does anyone know how I could make this setup more power efficient? I can't put the system to sleep, because it needs to be constantly monitoring in case a critter shows up (they show up at all hours). Would switching to the Arduino mini save power? I heard it's more efficient, but the spec sheet looks the same and I'd have to step down the voltage from my 12V batteries to power it. Any thoughts on how I could significantly increase my power efficiency?

Thanks a lot.
6  Using Arduino / Project Guidance / Re: Arduino as datalogger for RFID readers used in fish research on: February 27, 2012, 11:30:37 am
Thanks for your helpful replies.

The RFID readers we have use RS-232. Comm settings are 9600 bps, 8 bits/word, no parity, 1 stop bit, no flow control. RIght now the readers sends three wires (gnd, comm out, comm in ) that go into a RS-232 adapter.

The cable from the RFID readers to the datalogger is either 1 m or 10 m , because the RFID reader is sometimes placed in the antenna in the stream, but other times in a box on the bank with the datalogger. With our old system (Dell axim PDA/Mobile Monitor software) we had no problem sending the serial communications over 10 m of cable.

I'm not sure what the speed of the RFID means, but the readers can read multiple times per second. We can set them for a range of read speeds, ~ every second to perhaps 12-x per sec.

Thanks again for the help, sorry for the late replies--away from computer for the weekend.

7  Using Arduino / Project Guidance / Arduino as datalogger for RFID readers used in fish research on: February 24, 2012, 01:10:07 pm
I study the movements of fish in freshwater ecosystems in Alaska, USA. We use RFID readers from the cattle industry. The readers power antenna arrays, and when a fish with an RFID tag swims over one, the reader sends a tag code over serial communication.

Right now we use a buggy software program and old Dell Axim PDA's to record the tag code and give it a timestamp. The PDA's are the weakest link in our system and I want to replace them with a more simple, cheaper data logger.

I have a couple Arduino Unos that I use in camera traps and I absolutely love them--I'd like to see if I can use them for this research project as well. I have 2 major criteria:

1. Serial communications: I need a datalogger that can receive serial communications from 2 RFID readers at the same time. When it gets a tag code from reader A (which won't be identified as such) it needs to record: reader A, tag code, and the time of the read. Ideally it would have some sort of traffic control so that if it receives reads from both readers at the same time, it will record both. The RFID readers have 3 comm wires (in, out, ground) that we currently tie into an RS-232 adapter.

1. Clock: Having a reliable clock is critical, since the Arduino would need to record a timestamp for each tag code it gets from the RFID reader. We are monitoring for 3 months. Time drift of <30 min. across that time would be acceptable. The RFID sites are in extremely remote areas, and powered by 12V 50ah batteries. It would be nice if I could switch batteries (power on/off Arduino) without the clock resetting. We visit the sites every 7 days to change the 6V batteries that power the RFID readers, but ideally the dataloggers would go 2 weeks+ on a 12V 50 ah battery.

Thanks a lot for any advice on whether the Arduinos would be suitable for this project.

8  Using Arduino / General Electronics / Re: What kind of DC plug is this? on: December 13, 2011, 02:28:24 pm
Thanks so much for noticing that! I didn't see that tab. Hopefully I can track it down.
9  Using Arduino / General Electronics / What kind of DC plug is this? on: December 13, 2011, 01:14:53 am

Can anyone tell me what the plug pictured in this photo is? The plug delivers 8V of DC power into a battery eliminator that goes into a Canon 400D DSLR camera. The plug is 10 mm long and measures 2 mm across (outer diameter). I don't have anything fine enough to measure the inner hole, but probably 1.25 mm diameter or so.

The kit comes with 2 battery eliminators, but only one cable/plug, so I'd like to buy a second cable with a similar right angle plug. I searched digi-key, etc. and can't find anything with similar measurements. I was hoping someone might know what this is so I don't have to buy a second kit and waste all the material that I don't need.

Thanks a lot.
10  Using Arduino / Project Guidance / Re: Play mp3 tracks with Arduino on: December 13, 2011, 12:55:31 am
Thanks for the help. I gotta admit, after reading the comments for the mp3 shields and the amplifiers over on Sparkfun, it makes this look like a pain for someone at my electronics skill level. Since I don't have much time to work things out, so I may just run an ipod and speakers off a big SLA battery, then figure the mp3 shield out when I have more time.
11  Using Arduino / Project Guidance / Re: Play mp3 tracks with Arduino on: December 11, 2011, 04:13:35 pm
Thanks for the links. I think I'll go ahead and get one of the shields and fiddle with it.  I just saw this link on how to control an ipad with arduino:

Not sure which route is easier. Also not sure which would be easier to amplify and play off speakers.

12  Using Arduino / Project Guidance / Play mp3 tracks with Arduino on: December 11, 2011, 03:23:39 pm
I have an Arduino controlled motion activated camera that I use to photograph big furry critters. I'd like to lure some coyotes, bobcats, etc. to the camera with mp3 tracks of prey distress calls (e.g., a rabbit screeching).

I could use some advice on hardware options for playing mp3's with an Arduino. Ideally, the mp3 player would hold a few different files, and the Arduino could tell it which files to play. Also I'd like to be able to hook the player up to external speakers and make a decent amount of noise.

I have an ipod Nano that I could use, but I'm not sure how tricky it would be to both power it and control it through the single power/remote control port it has.

Thanks a lot for any help.
13  Using Arduino / Project Guidance / DC to DC adapters for camera trap on: October 23, 2011, 08:43:40 pm

I am running a camera trap, where a motion sensor triggers an SLR camera via an Arduino Uno. The SLR in turn fires two flashes with radio triggers. Right now my system's duration is limited by the 3V radio triggers, which last a couple days on two AAA batteries. I've been wiring the triggers to D-cell batteries, but I'd prefer to use 6V or 12V SLA batteries, since that's what the flashes themselves run on. I'm assuming the best way to so this would be with a DC to DC converter. I looked at 6V-3V converters, and I can't decide which output current to choose. There is no datasheet for my flash triggers, so I'm not sure what they can handle. The average level of amps they draw must be pretty low if they can go ~48 hours on 2 AAA batteries (40mA?).

Do you think the following converter would work? Thanks a lot for any feedback!

DC/DC Converter
DC / DC Converter O/P Type:Fixed
No. of Outputs:1
Input Voltage:4.5V to 9V
Power Rating:1.5W
Output Voltage:3.3V
Output Current:400mA
Approval Bodies:CE / CSA / EN / UL
Supply Voltage:5V
RoHS Compliant: Yes
14  Using Arduino / Programming Questions / Re: Take pictures at regular intervals on: August 12, 2011, 06:20:26 pm
Thanks so much for all the quick feedback! The example code is really helpful. The ambient light sensor is a good idea... I actually like some flash during the day too, but saving power is always good.
15  Using Arduino / Programming Questions / Take pictures at regular intervals on: August 10, 2011, 09:37:40 pm

I'm using an Arduino Uno to control a motion activated camera in Alaska. I've adapted a simple script I found on the internet and it works great. It basically says "if object is detected, then focus camera and take picture". I just got a new flash that powers off if not used for 30 minutes. I need to adapt my code so the camera takes a picture every 29 minutes, too keep the flash awake. 

Here's the abridged version of the the loop that is doing the work in my current code:

void loop(){
    if (digitalRead(PIRPin)) {   
        takePicture();    //function that activates focus and shutter pins to take picture
             } }

I would greatly appreciated any advice on how to modify this code so that it does it's current job, but also takes pictures at fixed intervals.

Thanks a lot

Link to pictures from this project:

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