This Thursday June 23 I will be teaching a small class about advanced MSP430 concepts. I2C, SPI ADC, SDA, TLV/flash memory, more about interrupts and maybe more. Source code, and material to be posted after the meetup, if interested please check out the meetup page for more info.
Tag Archives: ideas
TTL/MOS timer experiments
I have this dual 556 timer that i have wanted to use, just because it can take 15V and work with out an issue and as low as 3V. (thanks TI) So i was thinking that this had some potential to be used for RF or a fixed PWM signal. (personally i would like to pick up a few digital POTs and a digital cap to to create a DCO of some sort)
So far i have played with it and found some interesting things out.
TLC556 Dual Cmos Timer Data Sheet
My first goal was to get a 50% duty cycle from the chip, this was pretty easy just choosing the correct values for Ra and Rb, but you will have to do some math and you should use the equation out of the data sheet for your chip. My equati0n Period = tH + tL ~= CT (RA + 2RB) In 2, but if you need values closer to what is measured, you will have to break out the TI 8x and plug in tH = Ct (Ra + Rb) ln [ 3 - exp(-t PHL / Ct (Rb + Ron) ) ] + t PHL and Tl = Ct (Rb + Ron) ln [ 3 - exp(- t PHL/ CT(Ra + Rb)) ] + tPLH. I know these equations look difficult but as long as you plug in your values you will get close to what you measure on your oscilloscope. but i did this the fun way, use the first equation to get close to what you need then tweak the rest of the values until you get something close to what you want.
The values that i chose first were the Ra and Rb, I chose Ra = 220 ohms and Rb = 100 ohms and Ct = .0047 uF. Rl and Cl i did not choose a value nor did i hook up those components, i will have to look into the reason they are there, but i’m sure they are there for good reason. This first Test was just to make sure i can get a good square wave and be able to shape it.
the new values that i used are – will update later, but frequency is near 1 Mhz
My second goal was to try and make a sine wave or shape the square wave to be better for RF transmission. I added a Pi Network to the out put to shape the wave and below is what i got for half of the pi network, i will have better pics of the final wave form once my circuit is a little more complete.
another pic
and another
If all goes well and i can create a pretty stable transmitter i will be hooking up a small modem chip to the circuit and create a cheap digital modem . Another thing that would be nice would be a pair or transmitters and receivers so i can send and receive at the same time.
update-
R1 100 ohms
R2 220 ohms
C1 .0047uF
BPM Counter Display update
Filed under arduino, electronics, Hardware, software
Tagged as arduino, electronics, Hardware, ideas
Tagged as arduino, electronics, Hardware, ideas
I finished the display for the bpm counter!! Its amazing what you can do with a few transistors. I’m currently using 10 of the 14 digital pins on my board, but running three 7 segment LED displays. Parts include 10 NPN 2n2222 transistors and NPN 2n3904. 7 x 3.7K resistors and 2 dual 7 segment displays (only 3 being used).
Thanks to Codekiller, im going in a slightly different direction, he suggested to create a VU meter first and get a good reading, then start to create the algorithm to find out the bpm is. Timing will be essential to get an accurate calculation, and also to visually look at the graphed data the arduino puts out will help in creation of the bpm algorithm, from my experience in audio editing and mastering, I am pretty certain I can pick out the Beat and measure the time it takes for the next peak, doing this visually should not be to hard but putting it into a programming language and having it work may be a little challenging.
I am currently coding a quick gui to read and graph the values using The processing programing language(very easy to build visualization software and gui interfaces using a C like programming language). This may turn into a start of a simple oscilloscope later this year since i do need one for my bench.
Pics comming this morning when I get home from work(lol)and maybe a video if i can get it to work correctly. I am so happy that I have a radio shack within 5 mins from my place, and only have to wait till 9 am till they open.
Thanks Codekiller for the great help and ideas—> his site http://smfinc.web.elte.hu/ruckus/index.html
and the site Im using as a starting point —>http://interface.khm.de/index.php/lab/experiments/arduino-realtime-audio-processing/
at the time of this post the last link had a Database connection error in German, I will check in a day or so and if its still down, I will post the PDF and code that I’m using from there project.
Look for more updates Soon!!
Justin
update-
my camera is not function at this moment, im working on getting it fixed and recovering some of my pics, but work is continuing on my days off. (not to much time on work days) the audio circuit is done, just need to test .
almost ready to start my projects!
Its been a long while since I have been able to work on any of my projects. Very soon I will have my new work space setup! So, stay tuned, posts will be coming soon!!
Update: sugru, shapelock, and my break
I am so excited my Sugru order shipped a few days ago from the UK, I am really looking forward to testing this stuff out, and finally tested my shapelock- pics and movie to be posted soon. Works as its supposed to, no more scrounging for servo and motor mounts.
as for my break only a few weeks left before i start working on my projects, lots of updates and some great new ideas coming to plan…
Justin
