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Eggtimer Flight Computer 

Assembly Manual 

 

Board Rev D 

 

 
 

 

 
 

 
© 2013-2018 Eggtimer Rocketry 
All Rights Reserved 

Summary of Contents for Eggtimer Classic

Page 1: ...Eggtimer Flight Computer Assembly Manual Board Rev D 2013 2018 Eggtimer Rocketry All Rights Reserved ...

Page 2: ...need to perform a Master Reset See Appendix A in the Eggtimer Users Guide for details Thanks for buying an Eggtimer flight computer We re sure that you are ready to get started but before you do you will need to get some tools together The tools that you will need are ___ Low wattage soldering iron 15W or less with a fine tip ___ Fine rosin core solder 022 032 60 40 tin lead or similar lead free s...

Page 3: ...ad_free_guide pdf A low temperature Sn Ag Cu alloy is best look for one that melts at 217 C or lower and is suitable for high vibration applications European Union countries have a regulation known as RoHS Restriction on Hazardous Substances that prohibits the use of leaded solder in consumer products Kits such as the Eggtimer are exempt from this regulation however we abide by the principle regar...

Page 4: ...ed You should have the following parts check them off as you sort them Qty Description __ 1 Circuit board pre populated with surface mount sensor and memory __ 1 Atmel ATMEGA328P PU processor chip big 28 pin IC __ 2 MCT 6 Dual Optoisolators 8 pin chips __ 2 TIP120 Transistors 3 pins __ 1 LP2950 33 Voltage Regulator small black plastic part with 3 leads __ 1 3mm Red LED __ 1 3mm Yellow LED __ 1 Piz...

Page 5: ...Eggtimer however Avoid putting it on plastic surfaces that generate static and preferably put it together in a room that s not carpeted That being said it s very unlikely that you will zap any of the components in the Eggtimer with static electricity but consider yourself notified of the possibility Also note that some of the components are polarized i e it matters which way you put them in If you...

Page 6: ... for this First they add cost and weight although not much Secondly they add about to the height of the board which can make it a tight fit in 29mm motor or BT 55 body tubes Finally and most important components CAN be dislodged from sockets during a flight due to acceleration and vibration We have seen it happen and the results are not pretty particularly if you are doing electronic recovery syst...

Page 7: ...are a lot easier to fix then 28 If it looks good turn it back over and finish soldering the rest of the pins ___ Mount the Optoisolators Carefully remove the two MCT 6 optoisolator chips from the anti static foam or tube in which they were shipped Identify the notch at one end of the chip this notch needs to line up with the notch that s marked on the PC board Some chips don t have a notch they ha...

Page 8: ... holes on the board It has a little kink in the leads so it will stand off about 1 16 if you have the kink centered in the middle of the hole It s not polarized so you can t mount it incorrectly Turn over the board and solder the leads to the board ___ Mount the RED IND LED Insert the RED LED into the holes for the IND LED make sure that the LONG lead is in the hole maked LEDs are polarized if you...

Page 9: ...sure Turn the board over and solder the leads to the board Trim the leads flush Mounting the Resistors The resistors are going to be mounted vertically so you will need to bend one lead back against the body of the resistor in order to do this They aren t polarized but we like to have all of the color bands facing up to make it easier to identify them the fourth band is a tolerance band and will p...

Page 10: ...in place trimming the leads flush afterwards ___ Mount the 2 2K Resistors red red red bands Bend one lead back on each of the four 2 2K resistors Locate their positions on the board and insert the resistors in the board One is just to the left of the red LED one is just abovve the yellow LED and two are just to the left of the optoisolators Turn over the board and solder the resistors in place tri...

Page 11: ...tor in place trimming the leads flush afterwards ___ Mount the 4 7K resistors yellow violet red bands Bend one lead back on each of the four 4 7K resistors Locate their positions on the board just to the left of the silver pressure sensor near the top left side of the board and insert the resistors in the board Turn over the board and solder the resistors in place trimming the leads flush afterwar...

Page 12: ...ors and two just to the left of the optoisoltors Iinsert the resistors in the board Turn over the board and solder the resistors in place trimming the leads flush afterwards ___ Mount the 820 ohm resistors grey red brown bands Bend one lead back on each of the two 820 ohm resistors Locate their positions on the board just to the right of the optoisolators and insert the resistors in the board Turn...

Page 13: ...board and solder the leads to the board Trim the leads flush ___ Mount the 6 pin header Note that the header is not symmetrical one side of the pins is a little longer than the other side Insert the header into the holes at the front of the board using the SHORT side The LONG side should be on the TOP side of the board You will probably need to use masking tape to hold it in place you want to make...

Page 14: ...solder the leads to the pads Trim the leads flush ___ Mount the resonator Insert the 16 000 MHz resonator into the holes on the board marked XTAL making sure that it seats completely You may need to use some masking tape to hold it in place It is not polarized so it doesn t matter which way you mount it Turn over the board and solder the leads and trim if necessary ...

Page 15: ...Regulator Locate the ONE set of pads marked 3V and with a spare piece of resistor lead install a jumper across those pads You will probably need to hold it in place with some paper masking tape before you solder Turn the board over solder the jumper in place and trim the excess leads 4 5V 30V Option With Regulator Hold the regulator so that the leads face upwards GENTLY bend the center lead out 90...

Page 16: ... masking tape before you solder Turn the board over solder the jumpers in place and trim the excess leads Now install the regulator in its spot on the board next to the two jumpers making sure that it lines up with the outline silk screened on the board Hold it in place with some tape turn the board over and solder the regulator to the pads Trim the excess leads ...

Page 17: ...ng Insert the transistors into the board so that the metal tab is facing the front of the board the side with the header There is an outline of the transistors silk screened onto the top of the board the close parallel lines should line up with the tab Hold them in place with some paper masking tape turn the board over and solder them to the pads Trim the excess leads flush Bottom Mounting Hold on...

Page 18: ...he side with the header If you bent the transistor leads correctly the plastic side of the transistors will be laying against the bottom of the PC board Turn over the board and solder the leads to the pads ON THE TOP SIDE OF THE BOARD This is the only component that is soldered on the top of the board Trim the leads flush ...

Page 19: ...he battery switch pads Note that the headers stick out from the edge of the board about 1 16 this is normal since the pads are spaced so that the board size is minimized if you do not use the headers The locking tab should face the INSIDE of the board so that the open side of the headers face OUTSIDE the board Hold them down flush with the board using some masking tape turn the board over and sold...

Page 20: ...To terminate a wire in the pins strip the wire clean trim it down to about 1 16 insert the wire into the pin so that the crimp on the back will crimp over the end of the insulation and crimp using the tool You will need to solder some wires to the Eggtimer board in order to test it we like using the 4 stranded twisted pair wiring that s used with Ethernet network cables Get the cheapest ones you c...

Page 21: ...plugging those pins into the corresponding pin on the connector You will need to install the driver software for the USB TTL interface that you are using on your computer before you can use it The one that comes with the Eggtimer uses a Prolific PL2303TA USB serial chip your operating system may already have the drivers installed for it but if it does not you can get it at http www prolific com tw...

Page 22: ...t the big ones simply unravel a few from the strand cut them off from the strand leaving about 1 of wire on them and strip and tin about 1 8 from the wire Tack solder them to the pigtails of the Main and CHB channels Note NEVER test with a live deployment charge If you need to test your battery igniter combination use ONLY an igniter preferably at least 5 feet from you and the Eggtimer IMPORTANT Y...

Page 23: ...and blobby compared to a nice shiny tented solder joint If you have a cold solder joint it won t conduct well at the low power that the Eggtimer uses this could easily keep things from working If you have a cold solder joint heat it up and put just a little bit of solder on it the main idea is to get a little more flux on the joint If you have separate flux you can use that in place of the solder ...

Page 24: ...sure that you have the polarity correct The RED wires must go to the side and the BLACK wires must go to the side Check Your Power Switch If you have a power switch make sure that it s a simple SPST type so that when you close it it s simply bridging the SW terminals You don t HAVE to use a power switch if your battery is removable i e you are using some kind of connector between the battery and t...

Page 25: ...EDs READY ALED and BLED an external pizo buzzer BUZ and a switch on the SW terminals It s a cheap slide switch we recommend that you do not fly one of these get a Schurter 033 4501 rotary switch instead Note that this example is actually a RevC board but the connections are virtually the same on the RevD board as well We have also connected a pigtail to the RST line In a real flight you can twist ...

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