AutoSpeed - Buyers Guide - DIY Automotive Electronic Kits

Do-it-yourself electronic kits. What use could they possibly 'ave in my car? you're wondering. Well - we've gotta tell you - there's now a whole heap of home-solderer kits available that'll get you revved up. These can be bought right now through the three big Australian electronics outlets - Altronics, Dick Smith and Jaycar - and they're all genuine bargains!

So what do you get when you buy a DIY electronics kit?

Generally, the kits available in Australian electronics stores are of designs featured in the pages of electronics magazines Silicon Chip and Electronics Australia. A DIY electronics kit comprises a PCB (Printed Circuit Board), the necessary components (typically resistors, capacitors, transistors and diodes) plus a generous length of solder to make all the joints. For those of us that aren't electronic geniuses, the kits all come with a reprint of the original magazine article (complete with an overlay diagram), which show you how to piece the components together. However, in addition to these essential supplies, we'd also recommend that you have a pair of wire cutters, tweezers (to bend wire and hold smaller components) and a multimeter close at hand when constructing some of these kits.

While the majority of electronic projects developed by these magazines are well tested and thought through, some are not. An example is the Digital Air/Fuel Ratio Meter developed by Silicon Chip and available through many Australian electronics stores. Unless it is used with the designated (very expensive Bosch) probe and the probe temperature is kept constant (and that's pretty well impossible to do), the readings can be in error by 3-4 air/fuel ratios. (The much simpler 10-LED kit Mixture Meter discussed below doesn't make grand claims about accuracy and so is a good buy!) So don't always take as gospel what kit sellers tell you - though by the same token, most kits are pretty good at doing what they're claimed to do!

Remember too, when you're building a kit that if you get even one component in the wrong spot, or make just one bad solder joint, the kit won't work - and there's nothing more disappointing than looking at a dead kit. So all of these kits - even the simple ones - are best suited to someone who has some electronics experience.

Now, to give you an idea of what's on the market, here is our pick of the most practical and value-for-money DIY electronics packs...

Basic Car Alarm

Without a doubt, the cheapest way of getting an alarm into your car is with the $15 Altronics Basic Car Alarm kit. This unit works by monitoring the voltage of the car's electrical system, triggering an output relay whenever there's a sudden change. These voltage jumps occur whenever a door is opened and the interior light comes on (like when someone's picked your door lock and has opened the door). However, you - as the vehicle's owner - can get around tripping the alarm by flicking a remote mounted on/off switch (which should be hidden well out of view). Not switching the alarm off within a preset time will sound off the car's horn and - hopefully - attract the attention of any passers-by. A flashing "armed" LED is also included in the kit as a visual deterrent.

Difficulty rating: Relatively simple.

Interior Light Delay

If you don't own a high-spec vehicle, the chances are you're not enjoying the luxury of an interior light courtesy delay. Having the interior light burn for a few seconds once you've stepped aboard gives you time to put down your mobile phone, fasten your seatbelt and start the car. It's one of those little niceties that make things just that bit more harmonious. Now any car can now feature an interior light delay with Jaycar's simple $10.75 DIY kit. Assembled in around 30 minutes, this kit even has the grace of fading the interior light out progressively! A true luxury bargain.

Difficulty rating: Simple.

Turbo Cool Down Timer

Ahh, the mighty turbo timer - a frequently over-priced bit of gear. You can pay over $150 for one of these things if you like, but if you don't care much for the wank factor, get yourself a DIY kit from either Jaycar or Altronics. Like any turbo timer, the principle behind these identical units is to idle the engine for a short duration after the ignition is switched off (this helps the turbocharger to cool down thoroughly). Features include a 90 second time-out, under temperature disable and immobiliser campatibility. The $33.50 Jaycar version comes with a silk-screened case, while the $29.95 Altonics kit comes with a flanged box for easy mounting.

Difficulty rating: Moderate.

Mixture Meter

The Jaycar 10-LED mixture meter is - if you don't already know - a must-have for someone with a highly boosted turbocar, or someone who needs a bit of an air/fuel ratio tuning guide. By taking a voltage feed straight out of your EFI car's oxygen sensor, this kit displays the approximate air/fuel ratio on a 10 LED scale. This lets you see when your car's running abnormal mixtures - indicative of a mechanical problem or too much boost. Fourteen dollars thirty-two is a small price to pay considering the engine damage that might otherwise occur...

Difficulty rating: Simple.

(For more details, see: "Cheaply Monitoring Air/Fuel Ratios")

Screecher Car Alarm MK2

The Screecher car alarm has been available for quite a few years now. Unlike a conventional car alarm, the Screecher triggers a very loud piezo siren inside the cabin whenever an intruder is detected. The wail of this compact siren is so loud (116dB), it will either scare a potential thief into the weeds or deafen them if they decide to continue on. Of, course - being so loud - it's also likely that passers-by will also notice the break-in and take action. The Screecher includes exit and entry delays (entrance also includes a short soft-tone warning), an on/off switch (which you hide somewhere in the cabin) plus a flashing high-intensity LED. However, if desired, the siren can be mounted externally. The Screecher can be bought for only $33.50 from Jaycar electronics.

Difficulty rating: Relatively simple.

Low Fuel Indicator

Costing just $15.10 (through Dick Smith Electronics), this kit activates an on-dash light to tell you whenever the fuel level has fallen to below a preset level. It says, ""hey, it's to time to gas me up!" Any fuel tank with an internal fuel gauge sender can be used with this kit. Comes complete with dash light and a box. (It can also be used to switch a relay (or the light) when an engine management sensor exceeds a pre-set voltage!)

Difficulty rating: Simple.

Gear Change Indicator

A shift light can help you maximise your acceleration performance and protect the engine from over-revving. So why not spend $37.95 with Altronics to invest in this gear change indicator? The module comes with both visual and audible alarms (using a single LED and a buzzer) and - unlike many cheap shift indicators - can be configured for different shift rpm in each gear (up to 5 gears can be accommodated). This means you can set the warning to go off early in low gears so that you've got a little extra time to make the up-shift. And that's highly desirable in a high-powered car that flings the tacho needle off the scale in its higher rpm band!

Difficulty rating: Moderate.

Universal HEI (High Energy Ignition)

A HEI has several uses. It can boost performance and reduce the need for tune-ups (by keeping the spark plugs cleaner). This kit is adaptable to conventional points, twin points or reluctor ignition systems - however, you can chose to replace points with an optional hall-effect sensor (ZD1900) to further reduce maintenance. With an operating range between 4 to 22 volts, the HEI has a 0.9 second fixed spark duration and also comes with a tachometer output. Supplied for $55.95 (through Jaycar) is a heavy duty die-cast case for under-bonnet fitment of the module. It's most suitable for older cars.

Difficulty rating: Complex.

Low Voltage Cut-Out

It happens all the time. You're out working on your car and you've got its stereo cranked up for a little background music. A couple of hours later - when you've gotta rocket down for some parts before closing time - you need to start the car. Click-click, click-click... D'oh, the battery's been sucked completely flat! This low voltage battery cut-out kit will save you from this stress by automatically disconnecting the current flow whenever voltage drops to a preset level (between 10.9 and 11.9 volts). You can also configure it so that the battery re-connects after voltage has been charged back up to a safe level. Stress relief from Altronics for $24.95.

Difficulty rating: Relatively simple.

Programmable Electronic Ignition

Now don't get this confused with a good aftermarket ignition system, but the Jaycar Programmable Electronic Ignition is a suitable answer for someone wanting to set some basic ignition parameters. The system allows you to program the rpm that ignition advance begins, the rpm for full advance, maximum advance angle, rev limit, dwell angle, vacuum advance and - of course - the number of cylinders. Data is entered in real-time via a telephone-style keypad.

Another appealing feature is that you can enter two different sets of 'maps', which can be selected when the ignition is turned on. This gives you the ability to have preset ignition parameters for (say) premium unleaded or Avgas, or high and low boost settings. Thankfully, comprehensive programming instructions are included with this 3 hours-to-construct kit. Here it is - programmable ignition from Jaycar for only $72.95! It's most suitable for older cars.

Difficulty rating: Complex.

Engine Immobiliser MkII

This immobiliser doesn't stop a thief from starting the car; instead it'll repeatedly stall the car after about two seconds of running - making it appear that the vehicle has some sort of terminal problem. Tricky, eh? Cost is $33.50 through Jaycar, or Dick Smith's version can be had for $29.84.

Difficulty rating: Complex.

Plus, for a little extra, you can also upgrade the Immobiliser MkII to this combination keypad kit, which requires you to enter a 4 digit code to disable the system. The Jaycar keypad version retails for $19.11, while Dick Smith's is $24.05.

Difficulty rating: Complex.

Now if all these DIY kits sound pretty good to you, remember, this is just our teaser selection. Make sure you check out all the rest of the electronic kits that you can grab - they're truly fantastic!