Tiny ADS Interface

Tiny ADS Interface is a DIY diagnostic interface for older BMWs. It is the continuation of the almost free ADS interface. Or at least, it was meant to be. More than a year after the almost free ADS interface was released, people were still asking for a prebuilt interface and I still had nowhere to send them. So I decided to do an actual PCB layout. I went ahead and touched up the circuit some in the process, adding LEDs and some protection. One thing led to another and what was produced was a completely redesigned interface which is no longer true to the "discover and build it in an evening" concept.

It is, however, an ideal design for being produced in quantities of one to hundreds. I hope to be able to build these cheaply enough to provide a viable answer for the people wanting a DIY interface without the DIY assembly.

Of course, others are encouraged to download and build the design too. If you want something more durable than an almost free ADS interface and you want to build one yourself, this is a great option. You can send the gerbers to OSH Park, order the parts from Mouser, and assimilate some SMD assembly tutorials while you wait for the PCBs to arrive. Once you have everything you need, you should be able to assemble your Tiny ADS Interface in an afternoon if all goes well.



Dec. 20, 2020, 9:42 a.m.

How this circuit works? It seems it generates signal 0/10V on RxD of serial port. It can not work as RxD needs signal +-6V minimally. Anything between -+5V is forbiden area. There is no generator of negative voltage. This can not corectly work. IF somebody can use it it is probably because some nonstandard RS232 serial port. It needs some level shifter installed between this stuff and PC COM port. I expected this is included as this circuit is really overdesigned in its complexity.


Oct. 9, 2020, 6:04 a.m.

Здравствуй. Заказал этот интерфейс более двух месяцев назад, 5 августа. У меня нет ответа на письмо с вопросом, все ли в порядке или возникла проблема. Кажется, ожидание было потрачено зря? Следует ли мне просить PayPal вернуть мои деньги или вы когда-нибудь их отправите?
Have only tracking number from UPS UC000300773US. Can you help me??


Dec. 13, 2020, 8:12 a.m.

Привет, доставили ли они tinyads? Мне тоже надо - думаю, заказывать через сайт или нет


Sept. 27, 2020, 12:43 p.m.

Hi. I have ordered this interface more than month ago. I do not have ani response to my mail asking you if everything is ok or there is a problem. It seems it was wasted time to wait for it? Should I ask paypal to give me money back or you will eventually send it sometime?


Sept. 19, 2020, 10:48 a.m.

I have a problem with the TinyADS where it reads everything perfectly fine when ignition is turned on. However, when I turn on the car, it loses connection. On INPA it's not possible to see any data and on DIS it takes like a minute to read one amount of data and then loses connection again. It's not possible to monitor live sensor data. If it makes a difference, car is M50B25TU BMW E36.

Bosse Dahlgren

May 19, 2020, 1 a.m.

Hi , I order a Tiny interface for a couple of months ago, but i have NOT get any. Only have a tracking number from UPS UC002327178US. Can you help me??

Best Regards


May 19, 2020, 1:11 a.m.

Sorry for the trouble. Two months is longer than it should take to ship to any country. Let me know if the original shipping address is still ok to ship to and I'll reship it.

Stephen Price

Dec. 10, 2020, 8:58 a.m.


Hi, I have connected my tiny ads circuit board to my 20 pin plug. I pick INPA, as soon as I connect 20 pin plug, a red and green led come on and power and ignition lights go black and say on, on pc. As soon as I turn ignition switch on, led lights on pcb go out, and power and ignition on INPA turn off? Any ideas please

Bosse Dahlgren

May 25, 2020, 11:37 a.m.

What happen?? Do you reship my Tiny interface agian or not?????

Bosse Dahlgren

May 23, 2020, 11:26 p.m.

Hi again, do you reship my Tiny interface yet??

Bosse Dahlgren

May 19, 2020, 5:08 a.m.

Yes, the address is still the same:
Bosse Dahlgren
Raketgatan 3
603 75 Norrkoping

need help

Dec. 10, 2019, 9:22 a.m.

Hello! I bought your wonderful interface for diagnosing my E36 93 year release. Everything was fine, but one day I could not read the car ... Inpa, dis error IFh-010, any attempt to connect, the LEDs light up PWR, IGN, and the L-line flashes. Tell me what could be the problem? what details can be checked in the interface? sorry for bad English))


Dec. 19, 2019, 6:35 a.m.

Do you solved the problem yet? i just received the item few day ago and successful connect to the car only once but then same problem as yours


Jan. 25, 2020, 8:38 a.m.

Unfortunately not yet. I bow to the problem. rather in the adapter than in the car. In this thread, the seller is not responding ..


Aug. 1, 2019, 6:24 a.m.

Hi, I purchased this cable to use with pss-autosoft on a Dell D630 laptop running Windows XP SP3. I cannot get the INPA software to show Batt and IGN status after connecting to my car. Nor can I get it to connect to the ECU. Pss-autosoft support checked my software config and says everything is correct. I verified my serial port is working using the loop back test. Any way you suggest I test the cable to ensure it’s working properly? I only have a basic multimeter.


Sept. 5, 2019, 2:08 p.m.

I'm not sure what model car you are connecting to but what version of INPA are you running? I'm trying to get INPA w/TinyADS working with an E34 but the version of INPA (4.4.7) does not include the E34 configuration file so it's not an option while running INPA.


Sept. 11, 2019, 12:14 p.m.

I'm connecting INPA 5.0.2 to a 1995 E36. After correcting the wiring on the serial port side of my TinyADS cable, I have been able to connect with no problems and get the Batt and IGN status indicators working correctly. Thanks for your reply Jeff.


May 8, 2019, 4:14 a.m.

Can you tell me what type of MOSFETs are used at Q1,2,3,4,5? The other question: Where are the 3 components used on the bottom right of the schematic(4081, and the two capacitators)?
Thank you.


May 14, 2019, 7:27 p.m.

The FETs are BSS138BK in the BOM but it's not a very critical selection. The gate voltage provided by the circuit is 10V, which is an easy requirement to meet, and the on resistance of the FET doesn't need to be any lower than 1 ohm, which is also easy to meet. There are many different FETs that would work if you can't easily acquire BSS138BK.

The two capacitors at the bottom right are decoupling for U1 and U2. The 4081 part is unused. A 4081 has 4 AND gates inside the IC, but the circuit only needs 3, so one of them isn't needed and that's why the inputs are tied to VDD and the output is not connected to anything.


May 15, 2019, 3:08 p.m.

Thank's a lot!


May 5, 2019, 5:28 a.m.

Hello need your help). I packed some ads of adapters for your scheme and, and with all one and the same problem. Does not connect to machines in which the ads protocol. error 10 in inpa .In this time, normal communication with ms41.0 and ms 43 m54 / m52. that is, the part that is responsible for the ads does not work. Tell me please what part of the circuit look for an error? Thank you for the answer.

carlos pedrosa

March 9, 2019, 11:02 a.m.

I bought the tiny interface and making the rs232 cable now. CAn you help me with the 2 a3 pins of the cable? Are they direct or crossed?

MAny thanks



March 14, 2019, 10:29 p.m.

All wires are connected directly. None are crossed.

carlos pedrosa

March 17, 2019, 4:23 p.m.

Hi again
Thank you very much for your help. By the way, i'm trying to install DISv44 program ( not IPMA). Do you know if it is necessary fill the IP's in configuration section?
MAny thanks again.

felix remacha

Feb. 27, 2019, 6:09 a.m.

hola compre hace un tiempo una placa tiny a esta pagina y aun no he podido configurar para que funcione . tengo instalado inpa con un puerto nativo rs232 , lo conecto directo al puerto y el problema es que la funcion de ignition la hace al reves, cuando llave contacto en on ignition esta en off y con llave contacto on ignition esta on , necesito ayuda, mi correo es femachin@hotmail.com . gracias


Feb. 28, 2019, 9:23 p.m.

It's been a long time since I installed inpa but I seem to recall the reversed ignition indicator happening if inpa is configured for obd mode instead of ads mode. But I would definitely double check that with bimmerforums.com as that's where I learned everything about inpa and ads interfaces. I think it's probably still the best source of information anywhere.

Scott D'Vileskis

Nov. 9, 2017, 11:35 a.m.

Hi-- I just received your TinyADS interface from EBay-- I connected INPA up to my 1991 850i, and was able to communicate with the GM, LKM, IHKA, EKM, but was not able to talk to the either of the DME 1.7s nor the EML for my car. Thoughts? Can this interface handle Left Bank and Right Bank?

Also-- Do you kit the parts? I'd be interested in buying 5-10 and assembling them myself if it's advantageous to do so. I'm not interested in reselling them commercially, but perhaps just gifting/selling at cost to local BMW friends. Thanks!


Feb. 27, 2016, 8:32 a.m.

what program to open files


May 14, 2019, 9:21 p.m.

geda gschem for *.sch
geda pcb for *.pcb

Mike Snyder

Feb. 8, 2015, 8:50 a.m.

I am trying to bench test a 1993 BMW TCM and it does not seem to respond to a DS2 command so I am trying to understand if this interface will help with a 93 BMW TCM?



Feb. 10, 2015, 5:58 p.m.

Yes that falls right within the year range that an ADS interface is appropriate for, although I don't have such a module to test with to be absolutely certain.

Are you trying to send raw packets to it with something other than a diagnostic computer? So far everything I've seen from that era uses 9600 baud, and either odd or no parity. Some receive on K and some receive on L, but they all transmit on K. Also, some require the first byte to be sent at 5 baud before switching to 9600 baud. (it's called a slow wakeup)

The easiest way to determine the correct way to start talking to a particular module is to have INPA try to initiate communication for that module and check the serial port with a scope. You don't need an interface to do that. It may try sending the wakeup byte in a few different ways (K or L; different baud; different packet type; etc.) plus retries, but one of those ways will be the correct one for your module.


May 26, 2014, 2:37 p.m.

Is there a specific reason this does not work with a USB interface? Also would it work with a PCMCIA to RS232 adapter?


May 26, 2014, 4:14 p.m.

Yes, unfortunately there is a reason, and it is _almost_ entirely out of our control.

Although the hardware has no specific requirements, BMW unfortunately chose to program their ADS driver using an API that only works with traditional RS232 hardware. ("real" serial ports)

Therefore, the ADS driver fails to work properly with all USB RS232 ports and with some PCMCIA RS232 ports, depending on whether the PCMCIA card uses traditional RS232 hardware or instead merely has a USB RS232 chip stuffed inside it.

There is still some hope that this can change in the future. Someone needs to rewrite part of the ADS driver to use the more generic API which works with all kinds of serial ports including USB. This would be straightforward if we had the source code, but we haven't. My Windows hacking skills aren't up to the task, but there are presumably others out there who can do this.

If this ever happens, all ADS interfaces will be able to work with all USB and PCMCIA serial ports by using the new driver, and I'll surely go ahead and design a new ADS interface which features USB rather than RS232.


Aug. 23, 2016, 3:55 a.m.

How I can check PCMCIA adapter for supporting TinyADS before buying? This information will be very helpfull for TinyADS users.

I found 4 new adapters on ali, but not sure if they work for us http://www.aliexpress.com/a...

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