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I have been asked a few times If I would make a page on Mini z transponders, I will go through where you can buy direct and how to fit, as different types of mini z cars are wired different.

The company I have bought my Lap Counter from is

You can also buy your Transponders at the same place or you can buy from a model shop, but if you buy from a model shop make sure they work with the Lap Monitor you are buying., we have now found out that the one's we had bought from the model shop are now a old version EQUIPMENT and will explain the findings between the two later in the page. The company in France are very quick on delivery. The Lap Monitor works very good with your smart phone or a Tablet and so on, and so easy to setup, in conjunction with a Bluetooth speaker you then have a complete package.

The lap Monitor always faces to the out side of the track otherwise it will pick up your car at loads of spots of the track, What we have found is when facing the outside of the track if there is a white or reflective wall stick up a black tile or card to stop any bounces of the wall, to give you any false readings, this will be explained later on.


What we did find out was that depending on the size of the track anymore than 6 people at one go had trouble picking up anymore transponders and stand a chance of getting missed, my thoughts on this is the time it takes to read out the time and the drivers name, before the next driver. Maybe I have not tried this out but if you shorten the names to numbers then this may work. But this did not work either, what did work was by lengthening the track to a 10 second fastest lap we were able to read 8 drivers in a single race, so the problem was solved, the lenght of the track for this to happen is now over 60mtrs in length.


There are 3 different types of mini-z cars in the Transponder fitting styles, and will go through them one at a time to save confusion, and the way I connect the wires is my personal choice and can be done many more ways at your personal choice but some people aren't so DIY at things then others and would like to show that anyone can do it.







I have only been in to the mini-z side of the hobby since October / November 2019, so everything was new to me to do with this side of the hobby, so I had to listen to others and the local model shops that were to be the major supplier of the equipment and advice required to enable me to get on. So when the idea of a lap counter came up everyone agreed this was a great idea of the model shop to come up with and this led to purchasing from LAP MONITOR company for the system and the transponders, But now this group has moved on to a more enjoyable and competitive use of the track and facilities that go with it to enjoy there racing.   9 months ago. When our group the S.R.C Herts Mini-Z Racing Group that was started in February 2020 decided to purchase more Transponders from the company that made the Lap Monitor in October 2020, When they arrived I was shocked to find that the ones they have sent me were nothing like the ones we thought were the correct Lap Monitor ones. we found that the ones that were sold to us were a old version of the transponders from The LAP MONITOR COMPANY . But the older version of the transponders that were bought did have a few glitches that gave the timing results problems, many ways were tried to correct this like angling the Lap Monitor downwards and trying to stop any signal bouncing of the white wall and before connecting with the transponder in the car, also the Monitor would pick up the cars on other places of the track behind the monitor. Another problem was the positioning of the old Original transponder because of its shape it is very unbalanced and you have to have the led bulb facing the Lap monitor when the car goes past it. Plus it must also be in clear view through the car to see the lap monitor. or this would also cause a problem , when problems occur the Lap Monitor will record a time of 5 seconds or less, this seems to be the default of the Transponder.

When the groups tried the new version of  Transponder which have no led bulb it did not matter which direction the transponder is placed, even behind a non path way through the body shell to see the Monitor or even the wrong way around, and the shape is far better and easier to place on any car being square and the same width as the car's chassis. version.





Other findings that we found with the new version Transponder was there was no need to protect the white wall with a black tile anymore as there was no bouncing from the wall , and there was no reading the car anywhere else behind the Monitor like the cheap one and there was no position on the car you could not place the Transponder in view or hidden behind the chassis. What is very good of the LAP MONITOR COMPANY is they will load what ever number you want from 1 to 96 which is a great help when more racers are joining so there is no problems with duplications.

We as a group are now in the progression of changing over to the new version Transponders as the racing is getting more competitive.

I hope this helps and as always this is only my interpretation of the problems that were found and how we got around them.


The AWD Evo also like the RWD Evo does use the 4 way ISC connector to allow the Transponder to work, which makes the connecting up of the transponder very simple, plus which is even better the on / off switch under the base of the chassis does turn the transponder on with the car and also off. this is a big bonus and will also save battery life if forgotten.

new transponder (2)

All the photo's below are of the Original  and new version Transponder


Now at this angle you can see the all doing TX bulb of the transponder this does not light up but there is a surface mount l.e.d that does light up to tell you its working, the transponders bulb (TX) should always face the outside of the track, this was explained earlier. But with the new version Transponder it doesn't matter which way you mount it.

Now on AWD Evo's there are not many places you can fit the Transponder because of the position of the motor, so I found the place I choose to use was over the gyro location, this i found was perfect because it was flat and also held down the aerial from the RX board.

On the red and black wires that are clearly shown on the last two pictures black heat shrink can be seen I shorten the wires as they are always to long and to save any entanglement with the cars workings.

You would have also seen the number 73 on the transponder this is the number you would have to put into the smartphone or what ever you are going to use.

One thing you must make sure that the transponder bulb has a clear view out of the car body.



The RWD Evo is much like the AWD Evo that you can use the 4 way connector to power the Transponder, it can also be seen that this on is number 10. Now this time because of the motor not being in the way as its at the rear of the chassis the spring system for the rear of the chassis gets in the way so once again not many choices for the Transponder. Its also noticeable that the wires are cut back again to save room, what I have not mentioned is the Transponder is stuck down with velcro which is cheap and easy bought from Tescos, Wilkinsons or Ebay in either white or black for a couple of pounds.


This is a better picture that shows there is not much room for the transponder, What I would also advise is to put the number of the transponder on the bottom surface of the white front tab, this will save you taking the car apart to find out the number.


A standard stock car could be a RWD MMD and all the others that are not EVO's, They all have the 4 way connector but they can not be used for the Transducers only the light systems. Now in this picture there is a small white connector, you can use what type of connector you can get hold of, I choose this connector because of the size , plus you can buy them from RS and Ebay with the wires already fitted, yes you do need to cut short the wires where the heat shrinks are.


Now both ends of the connectors can be seen as can been seen are very small and are easy to hide under the body once fitted, now to connect the power side of the connector, remembering you always use the socket side of the connector for the live side from the batteries.

The black wire being the negative wire is fitted in a couple of ways. The first way is on the rear

At position (1) this is the pozi screw that holds the negative tags together.

Now you get hold of the (2) arrowed part with your fingers and place a small pozi screwdriver at Arrowed position (1) and remove screw now if you ok with soldering you can lift the tag arrowed (3) up and solder the black wire to it.

Then place it back the same way but don't over tighten the fixing.

Now the positive sive is done in just the same way as the other side, Hold on to Arrowed (1) unscrew Arrowed (2) and the earth tag I arrowed (3) and then solder.

But when replacing the parts don't over tighten.

red side_LI

Now for others that don't do soldering there is another way which works just as good, and that is to strip back the wires to bare the strands and twist each one so there is no loose wires on both the red and black wires as in the picture.

then as we went through before undo the screw and hold the black bit on the other side this will allow you once loose to put the wire under the first tag that sits on another tag and sandwich the wire between its a little fiddly but it does work . you will find that you can cut the bare wire down a bit as the picture shows it far to long. and then velcro the Transponder like we did for the others.


The reason for the twin connecotr is this can be changed from a EVO to a stock car and thr driver can keep the same Transponder number all night, it also saves from buying double the Transponders, any small connector will doeven a futaba connector.

twin connector transponder

I hope this helps any questions please click the button below

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