the ben heck show was brought to you byelement14 the electronic design community and online store built forengineers and hobbyists alike join now & browse the store at element14.com oh! hello and welcome back to the ben... oh wait, i'll just send this text message... heck show
when did 3d printing begin, in today's episode we're going to becontinuing the wait... okay, i don't need to read that notification we're going to be continuing the simple cell phone project that will allow us to make a bare-bonesphone unlike all the smartphones that are
distracting everyone today oh, hold on... alright the weather looks okay, let's getstarted! amazing builds, exclusive mods, cutting-edge ideas, electronics,engineering, and more every week on element14's the ben heck show i have my parser code mostly working so i can use my computer to simulate theradio module sending data back to the avr, so the avrwill ping it every few seconds and say like
"hey! what's the battery power? what'sthe signal strength?" and then the radio module will respondwith what it is, so what i'm gonna do is, i'mgonna type in what the radio module would say inresponse and the characters don't have to be exactbut they have to be in the right space so i'm gonna say that the battery is 99 percent and then thesecharacters don't really matter nor do these, okay. alright so then it takes 99 percent battery, dividesit by 10 so we have 0 through 10
lines of battery power here so now thebattery is almost full let's see if we can get it all the way full, let's say 100 there it goes, alright and the command to set the signalstrength is csq and let's say that it's got reallygood signal, i'm gonna say 31 okay so now the bars are all filled upand now let's say you've got really bad signal like if you're in this shop for instance oh no! only one bar of signal! alright, so now that we know the avr is interpreting those codes correctly
we can hook it into the radio and see ifwhen it asks for the codes if we can interpret the real codes fromthe radio like it's been doing these codes that have been typing it manually but see, this way i know that it worksbefore i hook it up to the radio to see if the signal reading is correct,we'll take it outside to get a reading and then take it to the back in the shop,where cell phones go to die to get a reading. okay here we areoutside we have three out of four bars which is prettygood and can you hear me now
and in the back in the shop we only getone bar as suspected but it shows that the meteris working i've come outside to make sure i can geta good signal and i'm gonna have alison call me usingmy phone to this sim card so i can see if i canhave a conversation with her using the small microphone and speaker. uh, go ahead alison! boy i sure hope alison calls me maybe someone's calling me! hello this is ben
hey ben, this is alison oh, how's it going? it's pretty good, can you hear me? yes, it's kind of disconcerting because ican hear you in the background but there's a lag to the cell phone call well appears like the microphone andheadphone work so yey! okay bye bye now that we know everything works it'stime to think about how we are actually
gonna build the phone unit itself so here's the phone module, i'm thinking itwill actually go like this over the battery and these headers willbe going the opposite direction actually so they can plug into a custom pcb that we're going to laser paint felix has been working on this,there's small surfacemount tac switches that'll take up less space and the phone module will actually pluginto the bottom of it here and then on the back of it we'll have themicrocontroller
so when it's put together like this,it will actually nest together pretty well and then we will have the screen the screen will go at the top like this and instead of putting it down into this pcbwe'll actually put it up into it because it'll actually, you knowtake up less space that way, if we put it above the pcb it makes it thicker, if we put itbelow the pcb it makes it thinner and then we'll probably put the speakeron one end and the microphone on the other so thetotal thickness of this it shouldn't be too bad
maybe about three quarters of an inchso it's not gonna be the thinnest thing on earth but we are going to try to keep thefootprint as small as possible basically on the xy not much bigger thanthis battery i'm going to be working on anenclosure design for the phone and felix is stuffing the pcb we made withparts so we can have our own phone system so we've got the double sided pcb and ben wants me to put the componentsonto it. i got the schematic up here and eagle cad for reference
and i figure i'll start with the diodes and then i'll put on the push buttons, and then on the back side i'll put on the microcontroller and thecrystal i think i'll use some of this sticky backing to help me keep this pcb flat and stable while i'm soldering.so now i've got all the diodes in place and next i'll put on the push buttons so i just put on all the buttons, thediodes are on, the buttons are in place. next i'm gonna put on a resistor, a capacitor, the crystal
and the ic. so i'm gonna put on this atmel atmega that's already been flashed and i got the datasheet up here to make sure i gotthe orientation proper on this circuit here i don't want to put it on upside down,or backwards or anything. so the crystals are on pins 7 & 8 which ihave right here that's where the crystals are so that's good and to help it stay in place while i solder it i'm gonna put on a little bit
of flux paste so that it doesn't move around so much and it will also help the solder flow i'm not really gonna put too much of it on because the solder that i have has a rosin-core. i'm going to put this otherhorseshoe tip on my soldering iron so it will help with this so now that i have it tacked in place with these two leads i'll go ahead and solder the restand will be ready to try it
felix has stuffed the pcb that we designed so let's take a look at it before we design the case alright so we have the array of buttons here and we've madethe wires all nice and flat for everything to fit inside the case we've built in the speaker right there here's our main power switch there'sthe oled screen and the back of it, we have the crystal, themicrocontroller, the power switch and the headers forprogramming which we don't really need anymore
and the header to attach the fona module.so we basically made this all modular so it goes together pretty simplyand it's also easy to take apart so we'll probably whip the antenna around this inside the case and then we've even installed themicrophone right there so that you know basically there's complete disconnect betweenthese two halves, you can remove them easily so as far as this is gonna go together, it will be basically like this alright yeah, so i'm gonna draw this into thecomputer and then we can 3d print a case and finish the build
here we are in adobe illustrator we have the pcb we designed, the switch, the oled the speaker and the microphones that'show that all goes together we also have keys that will go in front of itand the front panel which i believe i will make look like that with kinda cutsie message. we also have to draw on the battery for reference, behind it and the casing around it we also need to do a depth version of itsince we're starting in 2d the shows us how the cases will lock together, right there
and also the thickness of things likethe switches and the gap that we need for the usb portbecause you need to be able to stick the usb into it to charge it alright so i'm gonna take some of these files and make them on the laser and print the other ones on my 3d printer. let's go now it's time for a techtimeout it's really hard to put lavalier micsonto a t-shirt because the cord goes down here and you have todo your t-shirt like that... it's kind of at a bad angle, it's really meantfor collars, lapels, jackets
but you know a lot of people weart-shirts so i thought id be cool if i designed a little clip for it, checkthis out the mic goes on to the clip pointing straight up, there's even somelittle tabs here to put the cord around and then you just squeeze it under the shirt and it will keep it vertical for when you're talking andaway from your shirt obviously we can print black grey blueones for different colored shirts but this one shows up good on camera yeah so, necessity is the mother of 3d printing invention
i'm gonna have this object on thingiverse so if you need it for your production go ahead and download it i'm gonna put together the front half of itfirst, there's a structure which i 3d-printed a laser-cut plate which will look nice along with someuseful phrases for life a piece a plastic that goes in front of the screen and then the laser-cut keypad which felix assembled for me
and when it goes together it kinda looks like an ancient calculator but you know, that's kinda the point let's make sure i got this, okay yeah so there's a slot for the power switchand for the usb so i'll start by gluing the case together and then i will stick the components into it i'm gonna wrap the antenna inside the case you know so you can get a signal not in the shop though!
don't tell the axe murderers that, they'll be like: "hehehehe, you'll never escape the shop!" i shortened the leads on this battery andi'm gonna wrap sone capon tape around it to insulate it, and then we can stick it inthe back half with the case plug it in, and and that's pretty much it.there it is! the simple cell phone... simplify! because clutter is chaos well, that's all the time we have for today on the next episode of the ben heck show we're headed across the pond to england to go to emf camp
but don't worry, we're going to be taking some cool hacks and projects with us we'll see you then hey ben heck show fans beginning in september the ben heck show will no longer be available on the revision3 network. be sure to change your dial to watch us on youtube or over on theelement14 community as we continue to bring you great weekly builds and bonuscontent so it's like a boyband version of the spice girls? i don't think that would ever ever work we also discuss the challenges of making double sided pcb circuit boards...
redundant that and zigazig ah so i've just wired... i didn't even wire them, there's no wire in here but don't worry! we're gonna bring... ah shoot! i'll call you back
i think i'm just tired of filming things the ben heck show was brought to you by element14 the electronic design community and online store built for engineers and hobbyists alike join now and browse the store at element14.com
