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kxenos's Achievements


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  1. Take a look here http://blogs.arm.com/software-enablement/498-from-zero-to-boot-porting-android-to-your-arm-platform/ and here http://www.olimex.com/dev/index.html see "SAM9-L9261" under "ARM" category on the left. For buying stuff, depending on where you live, check Distrelec, Digikey, Mouser, Element14, Farnel or RS components. Also check ebay for some cheap (chinese) development boards though I wouldn't recommend them as a first project solution. google is your F1...
  2. ok, ok. We got it. It's not that difficult anyway. ARM processors are your best bet, I believe. Cortex M3, A7 and A9 will all do fine. Buy a development board either from a processor manufacturer (atmel, nxp, ti, nxp etc.) or an other vendor like olimex, keil iar etc. When your software is ready, copy the schematic of the dev. board you used and add or remove features accordingly. Kostantinos
  3. Hello, I wanted to put this project into Projects area but couldn't find the link so here it is. This schematic is part of a bigger project that was never completed. That means it's not complete, meaning that even though I believe that it will work ok, it has not been constructed. The firmware is not done also. Think of it more as a base or a starting point, if you want to start a project like this. The main functional requirements were 1. A regulated 3.3V @ 800mA power supply 2. Embedded 2 cell Li-ion battery pack 8.2V or 8.4V 3. Device should be usable even when battery is charging 4. User should have detailed information about battery status 5. Visual indication of status (On wall adapter/charging/charged/fault) 7. SPI interface w/ firmware update capability Description This circuit uses the MAX17015 Li-ion multicell battery charger. It charges a battery pack while providing current to the load. When it detects an external power source it switches the load to this source bu means of Q1 and N1 FETs. The output goes to 2 regulators. The MAX8718 acts as an always-on source for the internal circuits. You can shut it down if you want but I chose not to, because the stand-by current of the circuit is minimum. But if you let it running, finally it will drain the battery because it will switch off when the battery voltage will be less than 4V which is too late. If you don't want this, you can place a switch circuit to the /SHDN pin. The MAX1791 is a 3.3V/5V regulator and is controlled by the uC. The uC controlls the charge current by using PWM on pin PB1 or lets the default setting if PB1 is set as input. The default setting is controlled by R9. IINP is an analog voltage depending on the current drawn by the circuit so that the uC can calculate the power consumption. I'm really bored right now, so if you want to see what the other pins do, please read the datasheet of the 17015. The uC also controls 4 LEDs that indicate the power status of the device. The ISP pins are connected to the system header that goes to the system. That's why it's called a system header. Finally, the MAX17041 is a really cool fuel gauge. It communicates with the uC using I2C and can give detailed data about the battery status, aging etc. If you finally decide that you want to build this device, download the evaluation kit manuals for the maxim ICs because they provide schematics and other information about routing etc that will be very helpful. Bill of Materials C1 1uF 25V C2 4,7uF 25V C3 0.1uF C4 0.68uF C5 4.7uF 25V C6 4.7uF 25V C7 1uF C8 0.01uF C9 10uF 25V C10 1uF C11 0.1uF C12 10uF C13 1000pF C14 10nF C15 1000pF C16 1uF C17 10uF C18 10uF C19 1uF C20 0,1uF C21 220uF 10V C22 100nF C23 10uF D1 BAT54WS D2 BAT54WS D3 AC_OK LED WHITE D4 CH LED ORANGE D5 FAULT LED RED D6 CH_OK LED RED D9 ON LED GREEN J2 Power adapter mini jack J3 Battery connector 2 pin J4 System connector 10 pin L1 2uH L2 7uH N1 IRF9410PBF N2 2N7002K N3 FDS8884 N4 FDS6690AS N5 FDS8958A P1 FDS8958A Q1-A IRF7319PBF Q1-B IRF7319PBF R1 0.015 R2 100K R3 1K R4 100K R5 49.9K R6 22.5K R7 113K R8 2M R9 50K R10 10K R11 1K R12 4.7K R13 660R R14 150K R15 660R R16 0R02 R17 30.1K R18 10K R19 130K R20 30K R21 100K R22 660R R23 4.7K R24 10K R25 1K R26 660R R28 1M SW1 ON/OFF Switch Momentary contact N.O. U1 MAX17015B U2 MAX8718 U3 ATtiny48 ATtiny48 TQFP-32 U4 MAX17041 U5 MAX1791
  4. In 5 days I'm going to Uganda. We 're going to set up a small hospital in rural village on a mountain about 4500km alt. The major problem about infrastructure there is that there is no power supply. Because of this there is no refrigerator to store medicines, the microscope I just bought will work only until it's battery is discharged, and the people there are totally disconnected from the rest of the world. And because there are many places like this in these countries, it came to me that if I could install a solar panel and a rectifier/battery charger/inverter in the so called hospital (actually it's more like a small warehouse right now) and an other one in the so called school something good might come out. And because founding is the major issue in these things, I was thinking I (we) could design something on CC licence that could cost 1/10th of market prices and anyone that wants to help in places like this could build with drawing already published. The solution might be something like [cheap solar cells - 12V car batteries - custom circuit]. Who knows? Maybe later we figure out how to make solar cells by ourselves and don't even have to buy these. So, what do you think? Konstantinos
  5. I would suggest that you start by picking a suitable servo for your application. After this you will probably want to select a driver IC suitable for your motor. In order to select the driver IC you will have to think about the system that will tell the servo to move. Is it digital? Like a uC? Is it something simpler like a user pressing a button? When you start designing an application you start by the functional requirements. What do you want your system to do. The specs. After this you have to think about the non-functional requirements - if any. After this you start with a rough block design. I'm gonna have a block (a module, a circuit) that does this. An other block that does that, etc. You define the interconnection signals according to the requirements (mainly the functional ones) and the constrains. A requirement for example might be that you want to have fine control over the angle so you have to use a uC or CPLD and a feedback mechanism. A constrain might be that for example it's difficult to find ICs that drive the motor and have digital interface at a reasonable price for your budget. etc. And you go on like this, revisiting and improving your design until you feel that there is a fair possibility that it actually might work. You build it and then start debuging. muhahaha (satan's laugh!) Just kidding! :-) Really, starting is the half of it. Debugging is the rest! Konstantinos
  6. Probably the IC that came with the kit is of wrong type. (probably someone equally unlucky will have a board with 14 holes and an IC with 8 pins, and his kit also won't work). Try to google every code the board has on it in order to find the manufacturer and send them an e-mail. :-) Konstantinos
  7. If the PC doesn't already have a dev. driver for the device, your device has to send a mass storage media report so that it will be recognized as a flash drive so that the driver and/or the application can be installed. If you just want to bypass the usb lock that the admin or a script has done (usually through HKLM\SYSTEM\CurrentControlSet\...\...) you have to find an other way (and I think there are a couple or so). Usually admins or antivirus programs know what they are doing when they lock things down. As an admin myself, I hate it when people (or poorly implemented drivers or modules) compromise my so well thought security policy! :-) Konstantinos.
  8. My suggestion is: Use an ARM uC to capture, encode and store the signal into an external eeprom. Use an open source speech codec like SPEEX which is perfect for encoding speech with excellent quality into bitrates of 2kbps, 4kbps etc. With 8kbps you will have perfect results. With 8kbps audio bitrate, if you want to store 5min of audio you need 5min * 60sec = 300sec. 300sec * 8kbit/sec = 2400kbit or 300KB of data. Take a look at ST micro cortex M3 which is STM32*. There is an application note that does exactly that. It has the audio circuit around the uC for line input and line output. OLIMEX has a dev. kit that has implemented exactly this circuit. So all you have to do is load the code from ST and off you go. You don't even have to do a prototype for proof of concept. App. note.: http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/APPLICATION_NOTE/CD00204907.pdf dev. board: STM32-103STK link: http://www.olimex.com/dev/pdf/ARM/ST/STM32-103STK.pdf You will also have to use an external memory for the messages. The dev board has an SD/MMC connector so you might as well use this resource. Extra feature: Voice messages could be transferred into laptop or other device via sd card if you implement a known file system like FAT16. Hope I helped. Just registered today, so I'm excused for the delay, right? :-)
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