 I have a new newspaper parcel. So this is a gadget that just came through the post. It is a itty bitty space modulator. It's a kit device produced by itty bitty.space which I have just ordered. What it is is a fairly simple little gadget for providing basic internet access to old computers. What it does is you plug it into the serial port of a computer and it uses a ESP Wi-Fi module to simulate a Hayes AT modem and you can connect to telnet sites. Its main purpose is to allow old machines to contact internet-enabled bulletin boards. And today I am going to put this together. Now it should be obvious that I have cheated and opened this up before so I know what's in there. We have a small pile of passive components. The ESP8266 Wi-Fi module itself which is a beautiful thing. These were originally intended as Wi-Fi modems but it turns out that they were fairly easy to program and they've suddenly taken off suddenly being a couple of years now. As embedded devices in their own right they are absurdly cheap. This entire kit costs me about 10 francs. But the processor here is a 32-bit risk processor. It's a bizarre architecture of all of its own but it's got about half a meg of flash, quite a lot of RAM. It runs a proper real-time operating system. They're great little things. So the way this works is the module plugs on here up on a socket giving it a little stand. This is the serial connector and the whole thing plugs directly into the back of your computer or via an adapter to a nine pin port if you've got one. The RS232 port does not produce signals compatible with the serial port on the ESP which is expecting TTL voltages which is 0 volts and 5 volts for logic 0 and 1 respectively. But RS232 is weird and the voltages it uses are about minus 24 and plus 24 for I got that backwards so it's 1 and 0 respectively. 0 is the high voltage so it also comes with this which is a max 232 voltage converter which goes in here and apart from a handful of identical passive decoupling capacitors, smoothing capacitors, smoothing capacitors and a voltage regulator that is all there is to it. There's a mini USB socket which goes on there. Mini USB is the less popular version of small USB standard. It would be nice if it came with a micro USB socket because I've got more micro USB leads. Yeah there is nothing really more to say though it is a little bit interesting that it comes with a voltage regulator. Anyway I'm going to put it together now as I know the design works and then I will plug it into a real computer and see what happens. So there is one small modification we're going to make which is this Max 232 doesn't come with a socket but I rather like my ICs to be socketed in case I screw it up. So I've got some sockets here they are the wrong size unfortunately. These are 28 pin sockets which I got for a long ago pick project that never actually came to fruition. I've still got the pick somewhere and obviously it is way too big for this so I'm going to cut it down to size. Of course I forgot to actually get my hacksaw and vice when I started the video. Be right back. Okay I also took the opportunity to look up the LM117. It's just a 3.3 voltage regulator which is used to power the ESP so the inversion is either done in the Max 222 and I was wrong there as well or it's done by the ESP itself. The PCB is this rather cool a black coated job which is really good looking except it does make the tracks a little hard to see but the middle pin here is the out which is connected to this pin of the Max 232 and this pin of the ESP so but the ESP and the Max 232 are running off 3.3 volts. The Max 232 then generates the the weird RS 232 voltages internally all itself just one of the things that makes it really useful. So the notch must line up so we want the notch to be on the end we're keeping which means it's I just mark that with my thumbnail that pin we want to chop off it out. This is not a very good socket. Had I had more fourth sight I would have ordered one the right size. Just double check. Just saw here so wow this hacksaw is blunt. It's also quite loud as I'm recording this after 10 at night I don't really think I want to make too much noise otherwise the other people in my apartment block will complain. That's better. Actually before I I should try and get the pins out first that will make it much easier to saw through. So I need my favorite bent tip pliers and that just pushes out the other side. I should add that you don't need a socket for this it just soldering the chip straight onto the board is easy. I am just paranoid so I want a socket. There we go. Beautiful and elegant. Truly a pristine piece of engineering. Okay where are my side ouch. Just stabbed myself with the pins. Where are my side cutters? Well that was ridiculous. My camera didn't turn on when doing the last section of the video. Yeah well what I did was I trimmed the end of the socket with my IKEA workshop knife which is the same as a kitchen knife except in a workshop and then I soldered the socket on and I reminisced about how old the socket is which is probably about 15 years. Anyway you're not going to hear that now. The camera is actually rolling now so let's do the rest of it at least it wasn't particularly exciting. So the next thing I was going to do is the USB socket and USB sockets are dead painful because the pin spacing is pretty fine and my soldering is not that brilliant. Now this board seems to have tracks on this side and the grounding plane on this side. The grounding plane which is underneath the pretty black paint is connected to the shield here and I'm just going to have to peer more closely at this side to see if it's connected to any of these holes so I do not believe it is but actually you have tools for this to find this out for sure. So grounding hole that is not connected but this one here mark ground is yep yep right that hole is connected to ground so that will be the USB data ground as opposed to the shield they're not quite the same thing although they're nearly always connected together and on this side there is only one pin connected up which is this one which is power. This is only used to power the device because the serial port does not contain power itself so I think I am going to make my job a little easier and only solder that one pin. The four big mount points for the shield actually hold the socket in place so I'm going to use that to hold well to hold it down and not bother with the rest of the data pins so this will take lots of heat it's a structural solder and quite a lot of solder is that flat these pins have bent it hasn't actually going to have to take that off again this question is can I melt the solder before I burn myself yeah I just have to bend these back again but now I've made life really hard for myself because I'm going to have to get the solder out of that hole before I can solder the socket down again but again melt the solder it is only one hole so it's not too bad let's try and make these pins go in first one of them was unfortunately the data pin I need to solder down yeah these things are not really designed for humans there we go just double check all the data pins are in their holes so I just need to provide solder by heat here that solder melts it should all snap into place ow or I burn myself let's try the table you know in hindsight I should have done this component first okay right that is flush with the board it is held on securely by that hole I don't need to resolder it but I do need to provide structural solder to the other four points so heat solder heat solder right and now the data pin I checked to see if it's not bridged do you think that looks like a good joint on earth it's happening here bike of metals sticking out I think it's a it's a solder stalactite yes it is weird yeah some really strange effects sometimes when you have big chunks of cold metal and hot solder touching it okay now let's go for the big one this should be relatively straightforward again I don't need to do every pin and that luckily that clips in place firmly so it doesn't need any support but it will need an absolute shed ton of heat for these structural solder pads it's not even too melted on the other side yeah the big hole is only about half full but that's fine that will hold it into place and as with the USB socket I'm not going to solder all the pins partly because there are a million of them well 25 it's a db25 connector but also because that will make it's better just do that again on this side but also if I ever need to get this off again it will make things much much easier the only pins which are connected are this one and this one which is transmit and receive the rest of the pins are all to do with other forms of signaling dialing handshake that sort of thing a lot of which are now obsolete oh yeah and I do need to solder the ground pin and I suddenly realize I need to solder the ground pin of the USB socket too I think yeah let me get the meter again oh yeah these ones won't connect as worthy and in fact ground was labeled wasn't it it's labeled on this side it's the one in the middle it's this one right this one so I need to solder this pin and this little one here and provided there aren't any other grounds on the RS232 connector which to be honest I have no idea if there are an odd one let's stop being clever and just do them all it won't take long shouldn't be a check for flushness not I can do anything about it now oh it's fine yeah I have time to talk about that socket again now yeah uh the PIC project that I got the sockets for and I still have the PIC which I still haven't used oh I got not at my current place of work which I've been there for six years and it wasn't at the previous place of work which was Antics Labs which produced uh Game Middleware you've never heard of and I was there for four years and while it was technically at the previous place which was DAO Systems that produced an embedded operating system that you've never heard of called DAOS or possibly a late uh that it actually went bust halfway through and reinvented itself and I got the help of somebody who was laid off during the great laying off so that means that this would have been the first incarnation of the company which probably puts it mid to early 2000s making the socket which I hacked up about 15 years old and I was a little surprised that the pins hadn't corroded to such an extent the solder wouldn't take but it actually went on really easily just interesting it's not a very good socket it's the folded pin type rather than the rolled pin type which produced better contact of course the danger here is that I've now managed to short one of these pins to ground that shouldn't have been but they all look like decent joints actually I think I got lucky okay next step the ESP module comes with this little socket here which goes on there and this should be straightforward heat come on heat it's not heating up that looks straight looks like a joint it's not doing a good job of heating these pins it's better I think my tip might be oxidizing slightly as it were also I think the rings come loose the ring here holds the screwdriver tip on but I'm not going to touch it with my fingers because that would be crazy there we go okay so this module plugs on here it's held in nice and firmly you can see that's the chip itself couple of interface modules I have no idea what they do and this track here is the wi-fi antenna so the only thing remaining are the passive capacitors which are all the same they're all labeled 1047 and these are omnidirectional so it doesn't matter which way around they go and because they're all the same that makes soldering them on dead easy the only tricky bit is somehow managing to keep them straight if the gods had intended humans to do electronics then they would have given us more hands that's not so bad just for tidiness sake I want them all straight and with labels facing in the same direction okay and now I need to find a pair of snips these are not my normal side cutters because I have lost them they're probably right here on my workbench somewhere I really need to tidy this thing up I don't think these are going to work at all okay I think I'm actually going to have to go search for them found them okay now we cut these off put a finger on them while I do so to stop them pinging off everywhere one day I will do this and then discover that they've fallen inside of power supply or something when all the magic smoke comes out all my apartment burns down which would be a shame let's worry keep all my stuff okay don't want that wire so we now have all the passives in place we just need the one last component which is the voltage regulator and make sure that's straight I solder play heat add solder this thing has a hefty heat sink it is straight next pin last pin okay um also do you remember what I said earlier about not being oh that was my meter turning itself off about not being clever I'm actually going to do the other three pins here this actually isn't as bad as I thought there's enough solder on the soldering iron to do that one needs a tiny bit of solder okay and cut these pins off okay so I will now take it off camera and peer closely at it while I inspect some of the joints I do not see any obvious bridges okay I think that's good so I will just use a cotton bud to clean the flux off because apparently he's supposed to do that I only just discovered that cleaning the flux off is hard and it seems because PCBs are sharp I'm actually leaving traces of cotton on the wires so have a bit of swab with the other end and I think that will do it and it looks a bit grim because the IPA hasn't evaporated okay I believe I have now finished oh yeah I haven't plugged the components in so the ESP goes on here the ESP should be pre-programmed and the max 32 goes on here sure all the it's lined up there we go one assembled itty bitty space modulator and if there is an earth shattering kaboom when I apply the power I will not be entirely surprised right so I'm going to do some tidying up and then I'm going to find one of my old computers with the right kind of serial port and plug it in and see how it works all right it's time to test this sucker here we have my trusty px8 cpm laptop the most over designed z80 laptop ever produced it has a serial port on the back where they've apparently pen out so it comes with this adapter here so all we do to make this thing work is plug it in like so apply power like so oh and we even get a red light in the ESP board I did wonder whether there would be a power indicator for some description okay now we fire up the term program I think we want normal well we have a terminal let's try a t return no nothing interesting not ready uh the serial connection at this end only has transmit and receive so there's a hello exits it should be shift f5 so uh cts rts handshaking won't work so I wonder if that is turned on all right then I have switched computers to this amstrad in c200 which has a rather more flexible serial program and I confirmed it doesn't work so let us do some debugging and try to figure out what's wrong I have verified that the ESP module here is programmed it was shipped to me programmed so so this means that the chances are that I have done something wrong when putting it together in fact uh my suspicion is this socket here which because it's 15 years old has probably suffered from some corrosion and may not be making proper contact so what we're going to do is beep out the various solder connections and see whether uh everything is making proper contact so just unplug the ESP module just in case so we have the the two serial connections are here so this should be this pin should be connected to one of these pins in fact I can follow the track it should be this one this one I said hmm interesting just verify that no it's not that pin it's this pin or even this one okay and what about this one interesting so this pin should be follow that track again it's quite hard to see them it's these two I care about I think I've managed to get them muddled again yeah uh due to the way the light is shining off it I'm actually finding it very hard to follow the tracks from this angle because of the paint so in fact this goes around this one to here that makes contact and this one goes around this one to here okay so both of those two make contact the next thing I want to do is to make sure that it's actually connecting to the max 232 chip so this is going to involve holding that there yep that one and that one right those are both connected so what else could be wrong well there's the other direction which is from the other side of the max 232 to the ESP module which are are these two tracks here so I think that's this one again the same problem applies let me put a quick peer this pin and this one that's connected oh and this one okay and likewise I want to check that they are making proper contact to the max 232 yep and this one so there's power power needs to reach the max 232 I know power is reaching the ESP module because we could see the power light come on power is I've done a terrible job of cleaning the bottom of this but in fact be better if I hadn't that's the middle pin from the voltage converter goes to all of these and this one yep and ground is this one we don't check that interesting and you see power and ground are usually in opposite corners of the of a chip so I'd expect it to be this the ground the ground distribution happens on this side of the board is this copper sheet here so I suppose I could what I should do now is go and look up the max 232 data sheet to figure out what the pins are okay we've got the pin out in fact the pin outs from this angle so in fact the it's not using the standard layout so vcc and ground up in 16 and 15 so yep that's connected and power is the middle pin yep of the regulator that's here too yep so that suggests that the max 232 is properly hooked up so interesting what else could be wrong the capacitor joints some of these I mean they all look reasonable for me at least we know the usb works otherwise we wouldn't be getting power well there is another thing to try which is to hook it back up to the computer and then use a logic probe to check for activity so let's connect we need to connect the logic probe up to five volts it should actually be five volts grounded to this so okay that turned out not to be as bad as I thought but we now have the computer hooked up the logic probe all wired up you've got the pin out of the max 232 so if I type on the keyboard then data should flow into this thing and we should see activity on the max 232 with the logic probe and I believe that this one oh yeah so I can demonstrate that this is power logic one and this is ground logic zero so this should be data data in I believe it depends which way around tx and rx are interesting that one looks disconnected not seeing anything very interesting actually now there there is a thought which is you do get two types of serial cables because you get two types of serial device you essentially have master devices like computers and slave devices like modems the infamous serial null modem cable is designed for connecting two master devices together so effectively it pretends that there are two modems connected in the middle so you get two master sockets now this being a modem should be a slave device I think they're called terminal and something else uh the the plugs and sockets on the devices actually correspond and so because this has a a female socket on it my assumption is that this is a slave device and therefore I need a straight through serial cable which this is if this is actually a master device or in fact I'm wrong and this is a null modem cable then the data and the data lines come out in different pins so that is actually conceivable so I want to get at the bottom of this now let's hook the ground up again somehow that should do so here we have the two is this way up so I can see the connections now remember this is rs 232 voltage nothing nothing so it's conceivable it's the wrong kind of cable conceivable but but unlikely I have a null modem cable it should have a female on both ends so it won't actually plug into this it should plug into one of these a plug it is also conceivable that the computer here is not generating serial data properly I have it configured to a 308 n1 there is no option here for cts rts handshaking so that is another possibility in that this computer will not send to the device because the handshake lines tell it it's not allowed to this is what I think is happening with the px8 I had actually thought that this had a option to disable that so maybe I am going to need to switch to yet another different computer yeah let's find a different computer I'll go for an actual pc this time I was going to use my trusty to shiba t1000 but it appears to have broken down which is somewhat peculiar suspicious and disturbing I think the nike had battery pack is fried okay so fetch another computer and try again all right so here we have my trusty hacked chromebook running debby in the nooks with a usb serial device and it's set up using the screen terminal emulator 300 board and if we touch the logic probe to here and then press a key you can see the light flash so this is sending data to the module and if I turn all this off and I plug the esp module back in again and fire it up and I can see data coming out very slowly which you can't actually see because this thing's got an incredibly glossy screen but and then the camera just doesn't work properly with it it picks up reflections from everywhere but that is working so I think this means that both the computers I've tried this on want cts rts handshaking which the device does not provide that's a bit of a pain I wonder if there's a way around that see the thing is that most modern machines when you use serial they don't use cts rts in particular the very simple ttl serial interfaces that microcontrollers use which just have two pins which is tx and rx with no handshaking whatsoever the days of xon xoff and si so and cts rts handshaking are well and truly over but the two computers I tried it on being quite elderly seem to assume that it is a thing now it may be possible to spoof the handshaking lines the max 2 3 2 here does have some spare pins so I should be able to easily make it produce the relevant voltages and then I can wire them up to the pins of the connector if I tell the computer that it's always clear to send and always ready to receive then this should achieve the same thing as not having that as not honoring the handshake lines uh yeah I'm I mean the board works which is good but I can't demonstrate it on the computer I wanted to demonstrate it on let me have a think about that and come back again all right I have gone and looked up how hardware handshaking works now what this is for is to prevent the computer from sending data unless the device is ready for it the way this works is when the master wants to send some data to the slave it raises well it asserts the rts line which is request to send when the slave is ready for data to be transmitted uh the slave asserts the cts line clear to send uh these are pins uh four and five so that's where's my pointy thing uh this one and this one if you don't want to have anything to do with hardware flow control but you still want to support it all you need to do is to wire the two pins together so what happens is the master asserts request to send and then it looks at clear to send which it sees as asserted because it's just connected directly to the request to send line so this means that modifying this thing to do this ought to be very easy all we need to do is to solder these two pins together so let us do that I have a wire that's not a wire that's a piece of solder uh a wire somewhere come on a straight piece of wire trying to pick this up we have a straight piece of wire and all we're going to do is solder one end to here bend it in the middle and sold the other end to the pin next to it so to do this I need the soldering iron which is heating some some solder and something to hold the wire with such as my trusty pliers so i'm going to apply some solder to the middle of this try to apply some solder like so and here like so and just double check which pins I care about which is these two just bend this here to make it a little easier to get at uh this needs to be held down actually I shall just do a little bit of trimming first so I should really have some proper tweezers and in fact I do have some proper tweezers somewhere they're on my workbench along with everything else let's find something else to hold it down with like a small screwdriver possibly a magnetic small screwdriver it's not the right thing anyway solder that end solder that end and we should be done that looks like a reasonable joint so off with the soldering iron and then we get to get out the hardware again okay I've got the px8 out again I've configured the serial port plugged it all in we've got the terminal ready to go so let's fire that up 300 board 8n1 normal mode right the terminal is ready and plug it in and see what happens nothing let's return a couple of times 80 great well it was worth a try okay the logic probe is now enabled let's just try these pins just check I have to keep the screen it's exactly the right angle or it's not visible right logic one correct logic zero correct this one should be incoming data oh blink and lights right this means data is arriving at the max 232 which one of these is serial hmm so data is showing up at the max 232 but I don't see it going anywhere else I don't have the pin out to hand anymore so I'm just going to try all the pins that linear regulator is very hot I shorted something out I don't believe so this this loop of wire is connected to the right place otherwise this would have failed and you wouldn't be seeing data arriving the max 232 is not sending serial data so let's just unplug this connect things up again just let me just check the pins yeah it looks like the ones I'm looking for are the four pins in a row down here so we've got should be check's out mm-hmm so that looks like the max 232 is correctly translating data so let's plug this thing yeah we've got some garbage appearing on the screen let's plug this thing back in again you do have a red light I can't remember whether we've seen blue or red earlier data in no data out the only difference is the ESP module is plugged in let's just double check that one more time data in data out yeah the terminal got confused and gave up here we go success yeah I don't know what happened possibly it just got confused for some reason AT question mark tastic there's a lot of stuff here a lot of stuff here anyway let's just look at the settings which should be this one the speed dial is configured already I think this is dumping just seen that okay anyway let us try and connect and this is my Wi-Fi password I am going to pixelate it out let's try and connect to the Wi-Fi network ATC one connecting connected that was amazingly painless okay uh I want to dial the level 29 bbs s0 no last help again uh you can increase the board rate which will improve things no end 80 d s zero that's the one I want give us control c work no it doesn't right now it's set to 300 board which is the default and pretty slow there that command $80 sb changes the board rate I'm not going to do that just yet dial speed zero we're connected to level 29 we are bulletin boarding across the internet 80 by seven um ASCII excellent this terminal program supports x modem file transfers using the function keys so we can actually push pull pull and push stuff off the bbs uh I barely know how to use this so I'm not actually going to bother but this works that's excellent this computer will go up to I think 9600 board if you plug it into a machine with a rather better serial port like a pc this will go up to 115k board or something but most 8 bit machines don't go up anywhere near that far uh and in fact early PCs have really buggy uh serial uarts and don't like high bit rates you can get them to transfer correctly if you try hard enough but uh most people don't it's easy enough to upgrade the uart to something that's long not buggy uh yeah well that works cool um I am going to contact the manufacturer and suggest that these two pins get wired together on the board in the next revision because that will help things a lot for machines that require hardware handshaking but other than that this is a really easy kit to put together even with my levels of soldering skill I'm going to uh I think 3d print a box for it because this is a little bit frail uh yeah that's really useful and I certainly can't complain about the price so there we have the itty bitty modulator now finally working uh if you're interested do check them out they've got all the designs necessary to make your own if you want to uh and a few left from the current production run to sell I hope you enjoyed this video please let me know what you think in the comments