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emdarcher last won the day on June 18 2014

emdarcher had the most liked content!

About emdarcher

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    San Francisco, CA
  • Interests
    Tinkering, Inventing, Electronics, Robotics, FIRST, Linux, C, Engineering, Bushcraft, and many other things.
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  1. @@greeeg The 555 was mounted on the PCB in a circuit with the relative humidity sensor to give a frequency output from the change in capacitance. There may be a way to make a clever circuit to use the MSP430's Analog comparator, or the ADC for capacitance measurement, but I decided to just use the circuit on the board. If it was a resistive sensor, rather than capacitive, I would definitely use the ADC. As for the project, I haven't has as much time to work on it with school and stuff going on, and also many other side projects that I am messing around with, mostly using STM32 and AVR microcontrollers. Will maybe do some more on this project when I feel like it (also the entry didn't make it to the next round of the Hackaday Prize, so finishing it soon is not as much of a priority). I have so many project ideas, but of course never enough time to do all of them! Just the way it is.
  2. Here is my current project and entry for the Hackaday Prize: http://hackaday.io/project/2375-Garden_automation_and_sensor_network The main purpose originally was to have temperature monitoring of a small outdoor greenhouse, but then I decided to expand it from there. For more info look into the project page via the link above. Description originally from my hackaday projects page: This is a project to create a small network of sensors in the garden, and possibly some automation. The sensor data will be logged on an embedded Linux server (probably a Raspberry Pi or BeagleBone) and displayed on a web page. One such application for use is within a greenhouse, which may need to monitored in case it gets too hot for the plants, then venting of air could be automated, or the web page could alert the gardener. The nodes will consist of various sensors (temp, Humidity, soil moisture, etc.) attached to MSP430 microcontrollers which communicate using nRF24L01+ 2.4GHz tranceivers. Some will have Solar panels and rechargable batteries and others may have just a 3V button cell, but will last long by using the low power capabilies of the MSP430 and nRF24L01+. Final code github repository (for code when done): https://github.com/emdarcher/Garden_automation_and_sensor_network Prototyping code location on github: https://github.com/emdarcher/msp430-nrf24l01-testing/tree/master/sensor_comm YouTube video explaining the system (required for Hackaday Prize entry): Here is a pic of a prototype node, using internal temperature sensor and calibration data, as well as a HS1101 relative humidity sensor circuit with 555 timer. Prototype node and receiving launchpad to the left: Simplified diagram of Greenhouse node: Here is the system diagram:
  3. @@spirilis I would love to have the 1284p tqfn ic if it is still available. just getting into smd and seeking a more powerful avr to try out, so this seems like a good chip for that.
  4. @@zlalanne The l293d part needs a minimum of 4.5v on the datasheet , so i am supplying it with power straight from the 4-5 AA NiMH batteries to get 4.8 - 6V. The L293D was very picky and would stop working if under 4.5V ( battery strain with only 4 cells ), but as for the control logic, the 3.3V HIGH signals from the msp430 worked fine for the logic inputs on the L293D.
  5. Thanks for the great advice @@jpnorair ! I love taking things apart to find out how they work ( been doing that forever it seems ) and "taking apart", well seeing how the processor is doing things at a lower level is definitely interesting to me. I may try doing some assembler with msp430-as, the assembler that comes with mspgcc. I am trying to learn as much as I can with the resources I have, so far making projects is how I learn best. Currently am thinking of making a wireless sensor node inside a cheap solar garden light maybe using a nrf24l01+ module, but am likely going to implement it with an IR LED aimed at my window ( I am really cheap ). On a side note, do you know of any places where I could find an internship for the summer (paid or unpaid) in electrical or computer engineering in SF that would take a HS student with my level of experience? I just want to be able to get some work experience related to engineering, where I can possibly learn from other engineers. I have tried to get interships is the software side of things but never got replies, but either way I am much more into the embedded and hardware side of things. ( programming a game or app is just not as exciting to me compared to a microcontroller based device ). Thanks for any info!
  6. Recently finished my first msp430 based robot, a Basic Light seeker! This was a project to get me to learn more about the MSP430 microcontroller. In this project specifically, using multiple ADC inputs and PWMs ( 2 PWMs was a little tricky on the MSP430G2452 but eventually got it ). The robot turns according to the difference between the light values on the left and right, using two Photoresistors/LDRs. The robot is powered my a set of 4 to 5 NiMH 1.2-1.4V batteries which directly power the l293d Motor Driver IC and DC motors, and is also fed into a LP2950-33 3.3V LDO to provide regulated power to the MSP430G2452 IC and Photoresistors/LDRs. Most of my robot designs use a separate power supply for control and motors for stability, but this one has been fine so far and has an abundance of filtering caps. For a better description look at my blog post here: http://emdinventor-blog.tk/light-seeker-robot-with-msp430/ and for the code look at my github repository for the robot's code here: https://github.com/emdarcher/msp430_tank_robot Some pictures of the robot: Fritzing diagram ( missing 0.1uF filtering cap across Vcc and GND on the mcu ):
  7. @@SixSixSevenSeven @@dubnet @@Fred Yeah, I wasn't too confident about the MSP430 breadboard breakout, but was just interested. The 3.3V LDO board is small enough that I may squeeze it in the extra space with some later PCB designs. It is only around 3x1cm so could fit a couple in a 5x5cm board or in the empty areas on a 10x10cm board fabrication. When I design some other boards to get fabricated in the future I will probably add some of these small LDO boards in the layout. If I made a SMD version I could fit even more, just haven't ventured into SMD quite yet ( but some g2210 & g2230 ICs are coming as samples, so might try it as these are SOIC-8 packages). Still trying to coming up with ideas to make on PCBs and maybe some kits to sell.
  8. This is a project I made while I was learning about the MSP430's ADC10 peripheral and messing with multiplexing of 7-segment LED displays. It is a test bed for analog sensors where the 10-bit value of the analog input on the MSP430 mcu ( a MSP430G2252 in this case ) is displayed on two 2-digit 7-segment displays, which are being driven via a TPIC6B595N Power Shift register ( the SPI is currently bit-banged ). This has come quite handy for testing sensors quickly for my robotics projects and such. Here is my blog post that goes into the project in detail: http://emdinventor-blog.tk/msp430-based-analog-test-bed/ Github repository that contains the code for this project: https://github.com/emdarcher/msp430-7seg-mux1 pictures of the result:
  9. I have been working on a breadboard compatible Launchpad-based board for the DIP value-line MSP430s. I have finished an initial design in KiCAD, and am wondering if there is enough interest in this product before I get any PCBs fabricated, and to gauge how many I should produce. The main focus is to make MSP430G2 launchpad - like board that eases prototyping on a solderless breadboard, making small robotics platforms, etc. I originally designed this because I rarely use the Launchpad + boosterpack scheme, but instead usually use a value-line DIP ic on a breadboard and use the Launchpad's SBW to program them. This board will remove the breadboard setup step and let you get prototyping with some extra space on your breadboard! for a pcb + parts, my goal is around $7-8 and for bare pcb $3-5. For the option with parts, a MSP430G2452 will be the default ic to keep costs down, but if there is enough demand and I can make more, then the MSP430G2553 may be reasonable. here is a picture of a 3D render in KiCAD ( note missing push-buttons in the render ): This is only the second PCB I have ever designed, so there could be some improvement needed. Not sure if back GND plane or front Vcc plane are necessary. The back GND plane makes the most sense. Another product / accessory for this board is a small [LP2950-33] based 100mA 3.3V LDO board for breadboard power. It only has a 380mV dropout, so it can be used with 3.7V Li-ion/Li-poly batteries, so I will include a JST-PH receptacle for attaching them ( it is the connector that adafruit's li-polys use ). cost will be around $1-2 for bare pcb and around $2-3 for pcb and parts. here is a 3D render (note missing input header and JST jack, also the output header should be facing down, into the breadboard, but is facing up in this render): [LP2950-33]( http://www.ti.com/product/lp2950-33 ) [Tindie]( https://www.tindie.com/ ) I am planning on selling these products on [Tindie], and also in the 43oh Store if that is possible. I think Tindie has a fundraising feature so I will probably use that to get funds ( don't have enough money, just a teen still looking for a job for the summer ). Seeing the products by @@RobG on Tindie kind of inspired me to design some boards of my own. Any feedback/tips would be greatly appreciated!
  10. Hey, I am a rising high school senior who has been messing around and tinkering with electronics for as long as I can remember, soldered some kits starting in 3rd grade, first got introduced to programming with an Arduino about 2 years ago, Linux with a Raspberry Pi 1.5 years ago ( and then started tinkering with computers from my school's e-waste and installing Linux on everything, experimenting with running servers and SysAdmin stuff ), and now digging deeper into microcontrollers without the Arduino or Energia IDEs and their abstraction. Just finished my first robot ( a basic light seeker ) using a msp430g2452, programmed in C and compiled with mspgcc on linux, will probably share it soon! actually here is the code repository for it if interested (I expect it could use improvement would love any feedback): https://github.com/emdarcher/msp430_tank_robot the mspsci blog ( http://mspsci.blogspot.com/ ) has been extremely useful to me learning to use the on-chip peripherals and understand the datasheet and user guide. You can check out my blog here: http://emdinventor-blog.tk/ My school's FIRST robotics team: http://team4159.org/ I really like the msp430 microcontrollers ( just wish they had 5V tolerance like my little AVRs ) and am interested in taking better advantage of their low power cababilities. Also, I really want to go to BYU for college (and major in electrical engineering) and I recently found that their CS 124 ( http://students.cs.byu.edu/~cs124ta/ ) uses the msp430! So I am already learning stuff that could be useful in college, yay! (but they use CCS not mspgcc, so might have to adjust)
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