The Return of the Froggy Plip - 2009 Edition and beyond!

Froggers across the world have long lamented the gradual demise of their original Infra-Red(IR) Plip remote central locking systems, particularly since the Fuego is the world's first car to feature such sophistication. Nowadays radio technology has reached levels of miniaturisation that makes it feasible and economical to enhance the old Plip circuitry with a helping hand from tiny Ultra High Frequency (UHF) modules. I've sourced just the right modules, operating in the UHF band at a frequency of 433MHz and with a sophisticated code function to keep the most security conscious happy.

The Plip

The Fuego's Plip receiver (Rx), nestled between the visors, is a device whose function is basically no different from what you will find on the inside front face of your TV. Just behind where the smoked plastic window should be are a set of IR detectors whose job it is to sense the IR signal from the Plip keyfob transmitter (Tx) and have that energy amplified by the TEA 5500 Integrated Circuit (IC) and transistors on the original Rx module. The circuit diagram to the left is a result of my study of the module and track tracing back from the wiring loom on the back of the module, through the various discrete components and finally to the output pins on this IC. Since I intend to cut in at this point with the outputs of the new UHF receiver, I need go no further in my analysis.

The UHF Plip

I removed the original IC and fitted in its place a 7406 Open Collector Output Hex Inverter IC, able to translate the 5V active high outputs from the UHF module into the 12V active low outputs needed by the rest of the module's original circuit, back through to the wiring loom on its way to the central locking rocker switch in the car's centre console. I did this by desoldering the original chip and fitting the 7406, careful to cut and bridge the right tracks around the new pins so that the new chip's pinouts were compatible with the circuit. To the left you'll notice the introduction of the UHF module and the 7406 as well as the 7805 5V regulator and associated capacitors, whose job it is to provide 5V to the other two new devices from the car's 12V supply. By the way, the (Pin) numbers shown in these diagrams refer to the edge connector on the back of the Plip module.

Components

This is the Tx module, a tiny keyfob with extendable antenna (for extra range up to 200m) and four available buttons, of which we will select two for our use. If anyone can think up new uses for the other two, go for it. The Rx will use their signals as well. This little keyfob is tiny and features a sliding protective door so that the buttons won't accidentally be pressed when in your pocket. This is the UHF Rx module. The security encoding is achieved by pressing the surface mount button and activating the transmitter fob until the LED light flashes to acknowledge the code, just like programming a 'learning' universal remote control for your TV. In fact, with this module you can program over 100 separate fobs - the mind boggles! Since I ended up soldering the inverter chip into the old chip's position on the Plip board, I soldered the capacitors straight onto the legs of the regulator and then used just five 10cm lengths of lightweight single core insulated wire to connect this to both the original Plip board and the UHF Rx module. With the use of this wiring, the whole thing was slid neatly back into the Plip's original plastic housing between the visors and there is no sign of anything different - all original fit!

Pinouts

I spent a couple of minutes on the old Plip receiver module and central locking switch and sorted out some basic logic: Plip Rx Pinout 1 ground 2 one output 3 not used 4 the other output 5 not used 6 12V The connector on the back of the module is wired directly off the pins on the ... Central Locking Switch 1 lock output 2 ground 3 12V supply 4 illumination supply 5 unlock output Testing your Plip It's no good asking me whether I can modify your Plip without checking its condition first. To ascertain this, you'll need at least a half-metre length of wire and a Phillips head (cross-tip) screwdriver. Unscrew and remove the Plip box between the visors, extract your Plip circuit card completely and reconnect it to its wiring loom. Connect the length of wire to any part of the car's metal body (if your wire is long enough, pop the bonnet and hook it up to the negative terminal of the battery). Separately, one at a time with the other end of the wire, touch pins 3 and 4 on the TEA 5500 IC on the module - looking at this black 'caterpiller' with the module's wiring connected to the right, they are the 3rd and 4th pins along from the bottom left corner. If your locking activates when you touch these one at a time, you'll be able to use the circuit design shown here without any further modification. Let me know whether: 1. Yours works 2. You have it but it doesn't work 3. You at least have the connector inside the box 4. You have only a working switch on the panel If you are at option 1, then you'll be able to use the design shown here. All other options will require a couple of components added, so help yourselves, perform the test and let me know.

Here's a layman's wiring diagram for the project: Bottom line: if you're careful, good with a soldering iron and have a few components lying around, you should be able to achieve DIY UHF Plipping for around $50.00 (2009 estimate)

Happy Customer Tally! Congratulations to Australdi! You are the world's first Fuego GonzPlipper. I have to take second place despite designing the thing. Jo Proffi, come on down, you're the first Gen II GonzPlipper to hit the streets! Congratulations also to Fuego-go, Papster, KenFuego, Bob, Bazzamac(Fuego, Fuego Turbo and Alpine GTA V6 Turbo - first non-Fuego!) and RobJer (first Citroën GonzPlipper!) for joining the ranks of 200m Plipping.

Component Placement Getting it all in again... In the process of putting together 10 new plip kits, I couldn't remember just how much room there is in the box, so I went out to the Gonz Fuego and checked again. I was reminded of how neat I had made the installation. The diagram here shows how I provided plenty of lightweight wire between the three main clusters of components: the original plip receiver back in its customary black capsule (centre), the regulator and capacitors (left) and the new receiver module (right). This is how your Fuego will be retaining its original look without wiring, holes or hardware under the dash or in the engine bay. Here is a final look at GonzPlip production. - Australdi, Gonz, Jo Proffi, Fuego-go, Papster, KenFuego, Bob, Bazzamac and RobJer are all enjoying their new Plips. - 85Fuego is considering sending his in as part of a second parts purchase. I've created installation instructions for when you receive your Plips in the mail. Also, grab images of Fuego-go's Plip and the close-up of her box to see how the wiring emerges from inside the box. You can just make out that there's a split along the top of the shiny black plastic. If you need a new Plip for any French make or model, let me know in time for the next batch. This technology has already been proven on Plip systems other than Fuegos.

A quick visit to RobJer's place revealed what looks like standard Citroën RF plipping, only without a plip key. In order to adapt the Gonzplip idea to the Xsara, here's my GonzPlip Gen III design. This was wired straight into the wiring loom containing the input lines to the central locking module from the door switch. RobJer's is the first Citroën to carry a GonzPlip!