short circuits DIGITISER Instruction Manual

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DIGITISER

I N S T R U C T I O N M A N U A L

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Summary of Contents for short circuits DIGITISER

Page 1 DIGITISER I N S T R U C T I O N M A N U A L...
Page 2 The Kit DIGITISER R7-14 R1-4 Q1-4 7 4 H C 5 9 5 7 4 H C 5 9 5 Printed Circuit Board Components then applied. This is the silkscreen layer, which The Printed Circuit Board (PCB) is made of The kit comes with a veriety of components.
Page 3 Motherboard with other This is where you can learn how to solder kits from Short Circuits. Be sure to check out Use this table to identify the different compo- your components to the PCB. The tips at the the selection at www.shortcircuits.cc...
Page 4 DIGITISER The DIGITISER is a display output board with a few inputs thrown in, to let you control your device. The DIGITISER’s display consists of 4 x 7-segment displays. Each of these 7-segment displays has 7 LED’s inside that light up the different segments. Turning on different combina- tions of these segments enables you to display numbers, and even text.
Page 5 Kit Contents 4 x 7-Segment Displays 2 x 595 Shift Registers DIGITISER 2 x DIP-16 Sockets R1-4 R7-14 Q1-4 2 x 100nF Capacitors 4 x PNP Transistors 8 x 560Ω Resistors 7 4 H C 5 9 5 7 4 H C 5 9 5 1 x 2K Resistors 1 x 1.5K Resistor...
Page 6 Circuit - Symbols and Designations SCHEMATIC DESIGNATION Copper power trace Copper signal trace Copper trace on back of board Through hole solder pads Surface mount solder pads Resistor Ceramic capacitor Momentary Switch Potentiometer 7-Segment Display 74HC595 Shift Register PNP Transistor Screw terminal Connected to VCC Connected to GND plane...
Page 7 Circuit - PCB Design DIGITISER R1-4 R7-14 Q1-4 7 4 H C 5 9 5 7 4 H C 5 9 5 Ground (GND) Copper Area On Back of PCB...
Page 8 Circuit - Schematic Terminal Block IO Shift Registers 74HC595 74HC595 R7-14 LED-1 SEG-G SER OUT LED-2 SEG-F SRCLK LED-3 SEG-A SRCLK LED-4 SRCLR SRCLR SEG-B DIG-4 SEG-DP RCLK RCLK DIG-3 SEG-C DIG-2 SEG-D DIG-1 SEG-E QH’ QH’ SER OUT QH’ 100nF 100nF...
Page 9 Transistor Switches DIG_1 DIG_2 DIG_3 DIG_4 2N3906 2N3906 2N3906 2N3906 1.2K 1.2K 1.2K 1.2K 7-Segment Displays U1 - DIGIT 1 U2 - DIGIT 2 U3 - DIGIT 3 U4 - DIGIT 4 SEG-A SEG-A SEG-A SEG-A SEG-B SEG-B SEG-B SEG-B SEG-C SEG-C SEG-C...
Page 10 Bill of Materials (BOM) Designation Value Name Footprint / Pitch Datasheet C1, C2 100nF Ceramic Capacitor 2.54mm 3.2V, 20mA, Blue 3.2V, 20mA, Green 2.2V, 20mA, Orange 2V, 20mA, Red 11 x 2 pos Screw Terminals 3.5mm Q1 - Q4 2N3906 PNP Transistor TO-92 R1 - R4...
Page 11 Circuit - Shift Registers 74HC595 Shift Register (“sent high”), this tells the shift register that Output Enable data is going to be sent via the Serial pin. The The 74HC595 shift register is a Serial In, bits are sent to the Serial pin one at a time. Output Enable (OE) is used to instantly turn Parallel Out (SIPO) shift register.
Page 12 Circuit - Mode LEDs Shift Register Outputs Current Limiting Resistors Let’s first calculate the resistor value for each LED while ignoring the brightness. Let’s limit In our circuit, the LED’s anodes (+) are To prevent the LEDs from burning out, cur- the current to 0.0025A.
Page 13 Circuit - Transistor Switches PNP Transistors If none of the segments in the display are A Transistor can be used as a switch to apply pulled low, nothing will happen either, as there higher currents to a different part of the circuit will be no potential difference between the 5V with only a small amount of current to trigger coming from the Transistor and the cathodes...
Page 14 Circuit - Transistor Switches To ensure we turn the Transistor on fully we With these values we can calculate the value sistance needed. can use a lower Current Gain for our calcu- of our Base Resistors (R1-4). lation. There are different methods to ensure R = V R = 1250Ω...
Page 15 Circuit - 7-Segment Displays The Segments 7-segment displays are named after the 7 segments that, when all are on, show the number 8. By turning off different combi- nations, you are able to show numbers 0-9 and even a crude but readable A-Z. Not all 7-Segment displays have seven segments.
Page 16 Circuit - Switches The switches used in the Digitiser kit are Sin- which pins are connected when the switch When the switch is not pressed, the data gle Pole, Single Throw switches. These are is not pressed. line will read 0V as the line is pulled down...
Page 17 This Human Interface Devices (HIDs) include any- The Digitiser uses a ground plane to link all is done as little as possible. Care is taken to thing that humans use to control digital com-...
Page 18 Assembly Instructions General Soldering tips Resistors 4. SOLDER 1. ALWAYS KEEP YOUR TIP CLEAN R1-4 R5-6 R7-14 Leaded solder is much easier to work with, To ensure the soldering iron can transfer which makes it easier to learn with. It can enough heat from it to your solder/compo- be hard to find in some countries, but can nent leg you must keep the tip clean and...
Page 19 DIGITISER R7-14 R1-4 Q1-4 7 4 H C 5 9 5 7 4 H C 5 9 5...
Page 20 Assembly Instructions Switches and re-tinned. Potentiometer SW1, SW2 DIP16 Socket / 595 Shift Registers U5-6 Potentiometer Insert the legs of the Potentiometer into RV1 DIP16 Socket The switches will fit into their holes quite on the board. Hold the potentiometer with U5-6 tightly.
Page 21 DIGITISER R7-14 R1-4 Q1-4 7 4 H C 5 9 5 7 4 H C 5 9 5...
Page 22 Assembly Instructions Terminal Blocks you solder the LEDs! Solder the legs from the other side like the other components. Snip and re-flow. The terminal blocks are interlocking, so slide each of them together to make a chain of 11. To make this line of terminal blocks fit in their holes, you may need to squeeze the blocks together a bit.
Page 23 DIGITISER R7-14 R1-4 Q1-4 7 4 H C 5 9 5 7 4 H C 5 9 5...
Page 24 We can now connect the Digitiser to the diagram. The screw of the Vout terminal and the next page. This is where Vcc and GND Motherboard.
Page 25 es and follow the circuit back to the shift BACK registers output pin. If the same segment on each of the digits is not working, then check the resistor and the shift register output pin it is connected to. R7-14 If an LED isn’t working, check its connection R1-4 Q1-4...
Page 26 The following code example and explana- adding variables for pins, adding variables code, please refer to the Coding Basics sec- tion will test all of the Digitiser’s functions for other functions, assigning pins as out- tion of the Motherboard’s Manual. To help and teach you the basics.
Page 27 43). Here we use the function analogWrite, contained within the subsequent { } will be which requires the pin, followed by a value To display more information on the Digitiser’s executed. (from 0-255). Our pin is labeled OE and display than just the time, we will use one of the value has been saved in the potDimVal the switches to act as a mode select.
Page 28 Coding Basics - shiftOut use the equal to operator (==). If this is true, //Shift Out Digits the code withing the statement’s brackets will execute. if (mode == 1) We have 4 modes to cycle through. So we digitalWrite(LAT,LOW); need the value to increment 3 times, from shiftOut(SER,CLK,LSBFIRST,B11101011);...
Page 29 9 = B00001011 above should straighten that out. sketch. Upload it to your motherboard with the Digitiser connected to the correct Moth- To keep things simple in our example, we will Using the diagram we can determine the erboard pins and play around with it.
Page 30 If you are happy Remember to put a battery in the holder Connect the DIGITISER up to the MOTH- with the length, you can use it as a guide (BT1) of the Motherboard so the DS1307 ERBOARD as shown in the diagram.
Page 31 You can add sound levels and light levels above. You can switch outputs on the too, but we’re sticking with a simple clock SENSOR ARRAY and DIGITISER as long as Play around with the variables and code to and environment sensor display in this you switch to an IO port that has the same better understand it.
Page 32 Component Index Here you will find information about each component that this kit includes. We have included some of the different sizes and shapes you may find out in the wilderness, different uses for each component, and important data that can be found in datasheets to help you design circuits around them.
Page 33 Capacitor - Ceramic Overview Identification Quick Reference Capacitors are so named for their ability to tolerance Check store a certain capacity of electrical energy (J=5%) Polarity 104J (Capacitance), measured in farads (F). A certain amount of capacitance exists be- Positions first digit tween any two conductors that are in close multiplier...
Page 34 Capacitor - Ceramic Troubleshooting Common Uses Unlike electrolytic capacitors, ceramic ca- Decoupling Filtering pacitors rarely fail in normal use. However, if the voltage exceeds the datasheet’s rec- Capacitors are often used to protect cer- Unlike resistors, who’s resistance stays ommended maximum values (breakdown tain components from interference from constant no mater what frequency of sig- voltage), they can and will produce magic...
Page 35 Capacitor - Ceramic Low-Pass Filter cutoff Another form of filter that uses capacitors Input Output is an RC filter. The most common RC fil- ters are low-pass and high pass filters. As the name suggests, the low-pass filter lets low frequency signals pass but not high frequencies.
Page 36 Diode - LED Physical Construction Quick Reference Overview An LED is a Light Emitting Diode. Like all Check epoxy casing diodes, they are polarity sensitive. They are Polarity semiconductor light sources that emit light Positions when current flows through them. Different semiconductor materials produce photons Type active...
Page 37 Resistor Troubleshooting Overview Quick Reference If a resistor is bad you can usually tell. It Resistors do exactly that, they resist the Check likely went up in a puff of grey smoke. as flow of electrons through them. This resis- Polarity soon as you exceed the resistors power tance, measured in Ohms (Ω), is fixed and...
Page 38 Resistor Reading Resistor Values Surface Mount Surface mount resistors use a few coding systems. If you see just numbers, the re- sistor is probably using the E24 system. If it has a letter at the end then it is proba- bly E96.
Page 39 Resistor Through Hole Through hole resistors have 4 to 6 coloured bands which represent digits, a multiplier, tolerance and temperature coefficient. Use the following diagram to work out the re- sistors value. 4 Bands 22Ω ±1% 5 Bands 220Ω ±1% 6 Bands 220Ω...
Page 40 Resistor Ohm’s Law Ohms law is the most basic and useful piece of maths used in electronics. We try to keep things maths free, but this one is unavoidable. It describes the relationship between Resistance (R), Voltage (V), and Current (I). Ohm’s law states that the current through a conductor between two points is directly proportional to the voltage across the two...
Page 41 In our case, this would be 10K ohms. The po- tentiometer used in the Digitiser and Sen- sor Array kits have a tolerance of ±10%, so Slide Pot...
Page 42 Switch - Momentary (SPST) Overview Troubleshooting Quick Reference A momentary switch, or tactile switch, Most tactile switches have a dome shaped Check is a switch that will only be closed when contact that will spring back after you let Polarity pushed.
Page 43 Shift Register - 74HC595 Overview The best way to troubleshoot an IC is to Always check the max ratings and calcu- The 595 Shift Register is an 8-bit serial-in, swap it out and see if the circuit works late the amount of current going through parallel-out shift register.
Page 44 Shift Register - 74HC595 LATCH SRCLR Qh’ Power Serial Output Shift Register Clear Ground Serial Communication Output Enable Output Pin Connected to Terminal Block (DIGITISER, RGB MATRIX)
Page 45 Shift Register - 74HC595 Controlling the Shift Register The 595 shift register can hold 8 bits of data, which are received through its Serial data line. When the Clock pin pulses, the current value of the Serial pin is shifted into the register.
Page 46 Seven Segment Display Overview Quick Reference Common Anode Common Cathode G F + A B G F - A B A 7 Segment display module is an array 10 9 8 7 6 10 9 8 7 6 of LEDs in the shape of an eight. They are Check usually found in the single digit or 4 digit Polarity...
Page 47 Seven Segment Display 10 9 8 7 6 10 9 8 7 6 1 2 3 4 5 1 2 3 4 5 Common Anode Common Cathode Segment Cathode Segment Cathode...
Page 48 Transistor - BJT Overview free electrons, so is described as being positive. Transistors are a very important part of the electronics we use every day. There are bil- A Transistor has 3 terminals: Base, Collec- lions of them in modern CPUs. They can tor and Emitter.
Page 49 Transistor - BJT value. When in saturation mode we can This won’t tell you whether the transistor assume this is 10. 10 is overcompensating, is working within the datasheets specifi- but we are working in the saturation zone cations. If in doubt, swap it out. They are anyway, so we can safely over estimate to cheaper than chips.
Page 50 If you recognise anything as your own, and think you deserve a mention, please feel free to contact admin@shortcircuits.cc and let Martyn know. © 2021 Short Circuits™ Some Rights Reserved What is allowed? All circuits and schematics can be freely shared and modified as open source...