We are a family of four and so have four bicycles. Every time we want to use them, there are surely some tyres to top up. My compressor is in the garage /workshop and not easily accessible from where we store the bicycles. Hence, we have to use a hand pump and by the time I have finished pumping all the tyres I have lost the enthusiasm to go out with the bikes. Hence I needed a portable and quick to set up compressor.
Well I had some 5 litre containers lying around, an old computer power supply and a mini compressor that someone had given me a few years ago. Hence I decided to put them together, make a lazy mans portable compressor and recycle some waste!
I am sure the electronics experts are going to crucify me but I can take it!
I am not inventing anything but hope someone finds this instructable useful.
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Step 1: Safety First
Here we will be using a knife to cut holes and a drill, Always use protective gear and take all necessary precautions when using power tools. Read the instruction manual for your power tool carefully and pay particular attention to safety
ATTENTION: I am using an ATX power supply. Do not open the ATX power supply unless you know what you are doing. There are large capacitors inside and there is risk of electric shock from high voltage. It should not be necessary to open it.
Clean your container well before using.
Do not use containers that contained dangerous, toxic or inflammable substances. Instead, dispose of them properly according to your local laws. Do not disperse toxic or dangerous substances into the atmosphere.
The object in this instructable is only meant for filling bicycle tyre with air. Hence it should only be used for 5-10 minutes maximum. My particular compressor cuts out automatically after 10 minutes of use. Even though I use a cigar lighter type socket, it is not meant as cigar lighter or phone charger or any other function. If you use for any other function then do so at your own risk.
The device uses 12V and could cause fires in case of short circuit or over heating. If you do not know what you are doing then seek expert advice or do not do this instructable.
This device is only to be used out of doors on a dry day. Do not use in damp or humid conditions or near water.
This device should only be used by adults.
Disconnect the device from the power supply when not in use.
Do not leave unattended while in use.
Follow this instructable at your own risk. I will not accept responsibility for any damage or harm caused.
Step 2: What You Will Need
You will need:
1. A cigar /cigarette lighter socket.
2. Mini compressor (mine is 60W 5A)
3. Small switch (I used a toggle type)
4 Some LED lights and a couple of approx. 220 ohm resistors and heat shrink tube
5. Fuse holder
6. Old power supply (mine is a small 12V 10Amp)
Drawings are at the end of the instructable.
Step 3: Prepare the Container
As I mentioned, I used a 5 litre container that is normally used for liquids.
clean it out and make sure it is dried well. Do not use a container that contained harmful or inflammable liquids.
We will need to make some holes in the container (see drawings in PDF at the end) and will start with a window on the side that is big enough to allow the power supply to pass through.
1. On one of the larger sides, draw a square, 110mm from the base, 140mm x 140mm.
2. make a hole in each corner, using a drill, so that you can start the cut. I used a small drill bit first (5mm) and then a larger one (8 or 9mm).
3. cut the square out using scissors or knife. Take care because it is easy for the knife to slip and cut yourself.
Step 4: Cut Out for ATX Power Supply
I have loads of old ATX power supplies so I decided to use one of those for the power. I guess the electronics experts won't be happy to use a plastic container for such an application but, as you will see later, I put sheets of cork around the power supply to protect the container from heat. However, I should point out that the ATX is an old low power one. I guess another type of power supply could also be used.
ATTENTION: Do not open the ATX power supply unless you know what you are doing. There are large capacitors inside and there is risk of electric shock from high voltage. It should not be necessary to open it. If you want to clean dust from it, use a compressor and blow the dust out from the outside, there are plenty of ventilation holes. Wear a mask and do the job in a well ventilated area (outside for example).
1. If necessary, allow for the concave base of the container (some are concave).
2 There is a drawing at the end of the instructable that you can use as a template.
3. position the template approx 25mm from the base so that, if the base is concave, the weight of the ATX rests on the base.(see drawings at end)
3. Mark the fixing holes and then a square just inside (approx 5mm) the position of the holes.
4. Make 4 holes in each corner of the square and cut it out.
5. Check the ATX fits and that the fixing holes, in the container, line up with the holes in the ATX
Step 5: Cut Out for Fan
I decided to fit a fan for cooling the mini compressor and also the ATX power supply
I used a big 80mm fan and positioned it just above the ATX power supply (approx. 114mm from the base).
Seeing as the container is not closed, I used the fan to blow over everything and then out the other side. However, I am not an expert and it may be better to draw the heat out. Perhaps someone could suggest the best way.
1. position the fan where you want it and use it to draw the inner circle. Measure and draw the hole positions.
2. cut the inner circle. I used a sharp knife but scissors are probably better.
3. drill the fixing holes.
Step 6: Fitting the Power Supply and Fan
To protect the container from heat, I lined the inside of the container, with thin sheets of cork, where the power supply will be positioned. Then I fitted the pwer supply using the same special screws that were used to fit it to computer.
I next fitted the fan. It is possible put some thin aluminium grill over the top or, if you have a 3D printer, print a fan cover. You can find plenty on Thingiverse: https://www.thingiverse.com/
Step 7: Fixing Holes for Compressor.
The compressor needs to be fixed well and I thought the sides of the container were too thin and flexible for good support. There are also no suitable fixing holes on my compressor.
However, I noticed that the compressor does has 4 lateral supports for resting it on the ground and giving it a bit of stability. Hence I decided to make use of these and 4 cable ties to tie the compressor to the side of the container. For extra strength and support, I also used a piece of 5mm plastic sheet between the compressor and the wall of the container.
1. Cut a piece of plastic sheet large enough so that the compressor sits on it and with approx 5mm extra border all round.
2. Rest the compressor on the piece of plastic sheet and Mark the position of the supports
3. drill a hole on outside position of the supports, next to each line. The holes should be big enough for the cable ties to pass through.
Step 8: Fitting the Compressor - Preparations
For this step, you can take measurements or, if you have used a similar compressor, use the dimensions from my drawing. We will use the piece of plastic as a jig for drilling the holes.
1. Measure the distance from the end of the compressor to the rear supports.
2. Mark the centre of the narrow side of the piece plastic sheet and place it on the outside of one of the narrow sides of the container.
3. line the centre line of the piece of plastic with the join line of the container and above the position of the ATX power supply. Allow enough space so the end of the compressor will not touch the power supply. (use the measurement taken in step 1 above)
4. drill through the holes (previously made) in the piece of plastic so as to make corresponding holes in the plastic container.
Step 9: Fitting the Mini Compressor.
1. Place a sheet of cork on top of the ATX power supply.
2. Place the piece of plastic, on the inside of the container, on the side where the holes were drilled previously.
3. Place the compressor inside the container and on top of the piece of plastic.
4. Line up the holes, in the plastic sheet, with those in the container.
5. Fasten the compressor to the side of the container with cable ties. The cable ties need to pass through the holes ( in the plastic sheet and container next to the supports of the compressor) and then loop them back so they go back inside the container again.
6. fasten/ pull tightly around the supports of the compressor.
Step 10: Adding a Window
I wanted to be able to see the pressure gauge so added a window above it.
1. Draw a rectangle over the area where the pressure gauge is fitted.
2. Drill holes in each corner and cut out the rectangle.
Step 11: Fitting Plexiglass to the Window
I used a piece of 3mm plexiglass that I had lying around. The container is not very good for gluing things too and is too thin to screw things onto. Hence I decided to use small self tapping screws into the plexiglass.
1. I cut it just larger than the hole (approx 10mm is OK).
2. Drill a small hole in each corner of the plexiglass to suit the screws you will use. I drilled 2mm holes. I used the screws from old toys that I had dismantled.
3. Use the plexiglass as a jig and drill corresponding holes in the container.
4. Make a hole for the cigarette lighter. Mine is 22mm diam. I only had the cutting bit like in the photo. However, I thing is is better and safer to use a hole saw perhaps.
5. I also wanted ti fit some LED llights to show power ON and pump ON. Hence drill 2 holes for those too. The sizes depends on the LEDS you use and the LED holder. Mine are 6mm.
7. Finally I made a 6mm hole for the on off switch.
8. I tried to heat the plexiglass to make it slightly curved but it did not work very well. Perhaps better to use a thinner piece that bends but then there is not enough material for the screws.
9. Fit the plexiglass to the container.
Step 12: Wiring Cigarette Lighter Socket
Here I am going into deep water and must make reference to my favourite instructable on ATX power supplies:
https://www.instructables.com/id/Lab-ATX-Powersupp... Please read this before going any further. Be very careful with low voltage because, if connected badly/wrongly the high Amps can generate heat and cause fires.
I am not an expert on electronics so please forgive and correct me if I write something wrong.
My small compressor is 5W and 5A so I figured my 10A power supply should be more than enough.
I used a cigarette lighter socket that I bought at a local electronics fair for 2,00 Euro. I chose one with a cover/cap for extra protection when not in use.
I only used the wires going to the long 24 pin connector. So cut the 24 pin connector off. and leave the others.
1. for the cigarette lighter socket, I used 3 (yellow) wires from the 12V power supply so as to help avoid them getting hot. I then soldered them to a piece of 1.5mm mains wire and fitted a Faston which in turn I connected to one side of an automotive type fuse holder. I fitted a 8Amp fuse. I would have preferred to avoid the piece of 1.5mm wire but (apart from soldering the three wires directly) could see no other way because I could not fit the faston to the three wires.
2. connect a faston on each end of another piece of 1.5mm wire. Fit one end to the to the other side of the fuse holder and the other end to the positive connection on the cigarette lighter.
3. Take 3 ground wires and connect them to the centre (ground) connection of the cigarette lighter. I used an eye type terminal.
Make sure all connections are tight, keep wires as short as possible and use plenty of shrink tube to avoid short circuits.
Step 13: Adding Some LEDS and a Switch
The LEDS are optional but look nice.
Please check again this great instructable for details on ATX power supplies for further information:
I used the purple wire (standby) on the red LED
I used the grey wire (power good) green LED
I used the green wire for the switch.
For the RED LED:
solder a resistor to the longer (+) side of the LED. The resistor depends on the colour and voltage:
However, I used a 220 Ohm resistor for each because I had them lying around.
Solder the purple wire to the other end of the resistor
Solder the short leg (-ve) of the LED to the black negative wire. Use plenty of heat shrink tube over the bare wires to avoid short circuits.
I put heat shrink tube over the resistor too.
For the GREEN LED:
solder a resistor to the longer (+) side of the LED.
Solder the grey wire to the other end of the resistor
Solder the short leg (-ve) of the LED to the black negative wire. Use plenty of heat shrink tube over the bare wires to avoid short circuits. Again I put heat shrink tube over the resistor too.
For the switch:
I used a toggle switch but perhaps better to use a slider to avoid switching on by accident.
Solder the green wire to one pole and a black to the other. Again use plenty of heat shrink over the bare wires.
Double check all connections are correct, soldered well and insulated well
fix all the lose wires and make them as tidy as possible.
Put heat shrink on the ends of all the other wires that were cut previously but not used.
Step 14: Testing
Now you can test it!
Connect to the power supply, connect the compressor to the cigarette lighter and switch ON!
Please note that this is device is mainly for topping up the tires and not meant for prolonged use.
Enjoy your day out!!
Step 15: Here Are the Various Drawings
I have included some drawings but the dimensions are approximate and depend on the container used.
The drawings for the connections are quite basic. Let me know if there are mistakes or improvements to make.
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