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Stops ises if ‘scar ed’ e ey Fl mo c i Mthe e s u Mo es at ul g in h as g no Em J ’s oh n Cla rke kin ma use s sound t o en H e r d ar fi nd if hidd Draw s little p ow Mice make good pets but you still have to take care of them. This little critter doesn’t eat much (just the occasional lithium cell) and won’t make a mess or escape from its cage! B uilt on a mouse-shaped printed circuit board (PCB) and using relatively few parts, Mic the Mouse is ideal for fun and can be used to play pranks on family and friends. Mic the Mouse only produces squeaking sounds when everything is quiet. Make a noise, and he goes quiet. This makes him difficult to locate. He will start squeaking again, but only after a period of silence. Mic the Mouse (Mic for short) is best described as mousy coloured and mousy shaped. To further add to the realism, there is provision for whiskers. He sits vertically, with a slight lean backwards, and is supported at the rear using a stand that attaches to the back. Elephants and mice have been known in folklore and animations to have a unique relationship (see siliconchip.au/link/ac63), which is why the rear stand is reminiscent of an elephant’s rear end. Or perhaps it’s just because that’s a suitable shape to hold the mouse up. Nobody knows what happened to the front half of the elephant – except maybe Mic! It is also well-known that mice have a unique relationship with humans. The poem by Robert Burns, entitled “To a mouse”, begins: “The best laid plans of mice and men, often go awry and leave us nought but grief and pain for promised joy”. This couldn’t be more true with Mic the Mouse. Hunt him down you try, but Mic is elusive. He won’t reveal his 60 Silicon Chip whereabouts if you make any noise. But wait quietly and he will begin his merry squeaks again. Hide Mic in a cupboard, on a shelf, or simply in plain sight, and have others become horrifically aware that there is a mouse in the house. But where? You may be confronted by Mic’s eye flashing in a terrifying manner. Previous designs Way back in August 1990, we published an electronic cricket called Horace (siliconchip.au/Article/6925). Horace was similar to Mic the Mouse, except it chirped cricket sounds rather than producing mouse sounds. It only chirped when there was quiet, and was quiet himself when there was ambient noise. It utilised an electret microphone, quad op amp IC and a piezo transducer. This was powered by a 9V battery and its current draw was 3mA. With a 600mAh capacity, Horace could run for about 200 hours or about 8 days continuously. The reason for the “Horace” name has been lost in time. We published various updated cricket designs in December 1994, July 2011, June 2012 and October 2017, culminating in Silicon Chirp (April 2023). The reason for Mic’s name is a bit more straightforward. Firstly, it keeps up the tradition of alliterative names for animal characters like Dorothy the Dinosaur, Peppa Pig and so on. The other reason is that Mic uses a microphone to listen for sounds. Australia's electronics magazine To make Mic the Mouse a similar size to a real mouse, we need to use a few tricks. A 3V lithium cell is much smaller than a massive (by comparison) 9V battery. However, a 3V cell does not have as much capacity (200mAh, 600mWh) compared to a 9V battery (600mAh, 5.4Wh), so the current consumption needs to be kept as low as possible. To get a reasonable cell life, we need to reduce the current consumption from the 3mA of Horace the cricket down to at least 1mA to get the same cell life. However, we can do a lot better than that; we reduced the current draw to an overall average of 105μA. That’s a reduction of around 28 times compared to Horace! This was achieved by using a lowpower microphone and a microcontroller to mini mice (sorry, minimise) the current draw by only powering the microphone when required. Also, we only flash the LED eye momentarily to mini mice the power used. Like a real mouse, it sleeps to reduce its current consumption to an absolute minimum; it is woken up periodically by a timer. It’s a bit like hibernation, a trick Mic has stolen from bears. The low current microphone we use is a MEMS (micro-­electromechanical systems) type, as used in phones. It is supplied in a tiny package that measures just 2.75 × 1.85 × 0.95mm and requires reflow soldering as the contacts are underneath the package. That makes it difficult to hand-solder. siliconchip.com.au Coin cell warning! This project contains a small lithium ‘coin’ cell that represents a serious health risk should the cell be swallowed by a child. Young children are most at risk. Read the information sheet at www.schn.health.nsw.gov.au/factsheets on the dangers of small cells. Ensure that the cell is kept secured using the cell capture screw and nylon spacer and that it is tightened fully to prevent undoing by hand. Keep this project away from small children. Also, keep unused cells in a secure place away from children, such as in a locked medicine cupboard. New cells should be kept within the original secure packaging that requires scissors to open until required for use. If you have any older button/coin-cell powered devices that provide easy access to the cells, store them in a safe place when not in use. Alternatively, devise a method to make the cell access more difficult, such as gluing the cell compartment shut so that a child can’t open it. Fortunately, the MEMS microphone is available pre-soldered on an inexpensive module, which also includes an amplifier and 3V regulator. Circuit details Mic’s complete circuit is shown in Fig.1. It’s based around microcontroller IC1, a PIC16F15214-I/SN, powered by a 3V lithium cell (BAT1). Power is applied via a slider switch. Mic does not draw much current, typically only about 0.36μA while asleep. This rises to around 1mA when monitoring for ambient sounds and 1.6mA while making noise. Diode D1 is included as a safety measure to prevent damage to IC1 should the cell be inserted incorrectly. The cell holder doesn’t stop you from inserting the cell with the incorrect orientation (it should be positive side up). With the positive side down, the cell will be shorted out by contact with the sides and top spring contacts. However, during insertion, there could be a brief period when there is no contact with the cell holder sides, so the circuit could be supplied with a reversed polarity voltage that could damage IC1. In that case, D1 clamps this voltage to a low level. The cell will lose some of its capacity if left connected in reverse for more than a few seconds, but that’s better than damaging the chip. IC1 is clocked by an internal 4MHz oscillator. Its power supply pin is bypassed with a 1μF capacitor. IC1’s job is to supply power to and monitor the MEMS microphone module (MIC1) output, drive the piezo transducer to make mouse sounds, flash the LED used for Mic’s eye and also check if S2 is pressed. The MEMS microphone module (MIC1) is powered via IC1’s RA4 digital output, which goes high (near to the cell voltage) when required. When powered, the A output on the module (pin 3) provides an amplified signal from the MEMS microphone. The circuit of the microphone module that includes the MEMS microphone is shown within the dashed box in Fig.1. Its onboard regulator, U1, supplies 3V to the MEMS microphone itself (U3) and provides a bias voltage to pin 1 of the op amp, U2. U1 is a low-dropout regulator, so with a 3V input, its output won’t be much below that. The output from the MEMS microphone (U3) is amplified by op amp U2, which is configured with a gain of 50. The non-inverting input is held at half supply using the two 10kW divider resistors across the 3V supply. So, with a 3V supply to the MEMS module, the DC output from U2 is typically at 1.5V. A MEMS module output signal when subject to noise is shown in Scope 1. For data on the MEMS microphone and module, see siliconchip.au/link/ ac64 and siliconchip.au/link/ac65 The current consumption of the MEMS module is typically 287μA at 3V. That’s the total of U1 (7μA typical, 15μA maximum), U2 (80μA typical, 185μA maximum) and U3 (50μA typical, 150μA maximum). The voltage divider comprising the two 10kW resistors in series across the 3V supply also contributes 150μA. We measured our module’s draw as 330μA. The PIC16F15214 (IC1) monitors the microphone signal using its AN5 analog input. We have AC-coupled MIC1’s output to that pin using a 100nF capacitor and biased the voltage to 0V via a 10kW resistor. This has the signal at the AN5 input (pin 2) normally sitting Fig.1: the components inside the dashed cyan box are on the MEMS microphone module. IC1 monitors its output and determines when to flash the eye LED and create squeaking noises using the piezo sounder. siliconchip.com.au Australia's electronics magazine August 2025  61 Scope 1: this oscilloscope trace shows the output from the MEMS microphone module after AC coupling to the AN5 input (pin 2) of IC1. The signal level goes above 100mV peak. close to 0V and swinging above and below that. A diode clamp internal to pin 2 of IC1 will limit negative excursion to -0.3V, while the 1kW series resistor limits the current in the clamping diode. We do this so that pin 2 sits near 0V with no signal (ie, silence). Also, while the 10kW/10kW resistive divider in the module theoretically causes the signal to sit at exactly half the supply voltage, the supply voltage can vary because it’s coming from a microcontroller output which has a fairly significant output impedance of around 116W. That means that supply to the MEMS module can be anywhere between about 33-58mV less than the IC1 supply due to the voltage drop at the RA4 output. The MEMS module current draw also varies, so it is difficult to predict the MEMS module’s idle output voltage with sufficient accuracy to allow for threshold detection of any small signal that is superimposed on it. Re-biasing the signal to 0V solves this difficulty. Noise detection To detect ambient noise, we convert the voltage at the AN5 input into a 9-bit digital value every 1ms (1000 times per second). The digital value ranges from 0 to 511. If this exceeds a specific threshold value, it is detected as noise. This threshold can be adjusted between 1 and 10 in ten steps, corresponding to an analog range of about 12-65mV (assuming a 3V supply). 62 Silicon Chip Scope 2: the RA0 (yellow) and RA1 (cyan) output waveforms when producing mouse sounds. The signal bursts vary randomly in length, with variable periods of silence in between. It isn’t obvious from this that the signal frequencies and duty cycles also vary. Lower threshold settings give Mic a greater sensitivity to noise. More on this later. Mouse sounds IC1’s RA0 and RA1 output pins drive the piezo transducer to produce the mouse noises. The piezo is driven in bridge mode by the two outputs, increasing the AC voltage across it to produce a louder sound. When the RA0 output is high, RA1 is low and vice versa. In one condition, there is +3V across the piezo transducer, and in the other, -3V. This results in a 6V peak-to-peak square wave. A 100W resistor limits the peak current into the transducer’s capacitive load as the outputs switch. The mouse sounds comprise various frequency bursts with variable length gaps in-between. The signal frequency varies between bursts and also within each burst. Scope 2 shows three such bursts. While not visible in Scope 2, there is considerable detail within each signal burst. At the beginning of each burst, the duty cycle starts off quite low. This means the piezo transducer is driven only with brief pulses, resulting in a low volume. As the duty cycle increases, the output from the piezo transducer also increases. The duty cycle is increased a little each cycle until it reaches a 50%. A similar change in the duty cycle occurs at the end of each burst. The duty cycle is reduced on each cycle until it reaches zero, so that the volume Australia's electronics magazine falls back to zero. This gives the signal bursts soft starts and soft finishes, preventing loud clicking sounds from being produced by the piezo transducer at the beginning and end of each burst. We also use lower duty cycles to reduce the volume level within each burst instead of having a constant level. A varying volume level sounds more natural. The greatest volume available from the piezo transducer is when it is driven at 50% duty, as shown in Scope 3. The push-pull drive from the RA0 and RA1 outputs is visible too. This is necessary to provide a sufficient sound level from a supply voltage of just 3V or less. The drive frequency also varies over the burst period. If we were to just have the same frequency throughout, it would sound just like bursts of a single tone, like Morse Code. By having a frequency mix, the bursts sound considerably less electronic in nature. Mic’s eye LED1 is driven via the RA2 output via a 1kW current-limiting resistor. This LED is made to flicker when Mic is producing sound. The LED is also used to indicate the threshold level used to detect ambient noise during the setup process. It flashes between one and ten times to indicate the chosen threshold value. The LED also flashes briefly when Mic is powered up to acknowledge this. Pushbutton S2 is used to set this siliconchip.com.au Scope 3: an expanded view of the drive to the piezo transducer, showing how the ~3V peak square wave signals from RA0 & RA1 (yellow and cyan) combine to form a 6V peak-to-peak square wave across the transducer (red trace). The duty cycle here is near 50%. threshold. IC1 detects that S2 is closed by monitoring its pin 4 digital input (RA3). When S2 is pressed (closed), the voltage is close to 0V. When the switch is open, an internal pullup current in IC1 keeps the RA3 input high. The S2 switch closure is only checked during power-up; if it’s low (closed) then, the threshold setup process starts. Power control Much of the design work went into minimising the current draw from the small 3V cell. Shutting down the circuit is the major way to do this. When IC1 is in sleep mode, its oscillator is off and the power supplies to the MEMS module and LED are also switched off. A separate ‘watchdog’ timer starts running in sleep mode, to wake IC1 periodically. This varies between 4, 8, 16, 32, 64, 128 and 256 seconds in a randomised order. To extend the sleep periods and save more power, IC1 is sent back to sleep immediately upon waking 30 times. This provides an off-time between two minutes (when there is a 4s watchdog timeout) and about two hours for the 256s timeout. During this period, the current consumption is very low; we measured this at 0.36μA with a 3V supply. IC1 itself draws just 0.9μA in sleep mode, including the watchdog timer and oscillator current draws. After these 30 sleep periods, IC1 powers up the MEMS microphone module and checks for ambient sound. During this period, its current siliconchip.com.au Scope 4: this is similar to what’s shown in Scope 3, except the duty cycle is lower, at around 20%. This reduces the output sound level. consumption is about 1mA. This is mainly due to the MEMS module consumption at about 330μA, and IC1 drawing around 660μA while running. There needs to be a 2-16 minute quiet period (again a randomised value; it’s either 2m, 4m, 8m or 16m) before it is deemed to be quiet enough for the mouse to make noises. Should noises be detected during the listening period, IC1 will go back to sleep for another randomly chosen sleep period. If no sound was detected, Mic the Mouse will begin to make mouse sounds. During this time, his current consumption is around 1.6mA. These sounds run over a variable-length period between 100ms and two minutes; a typical duration is around 30 seconds. If noise is detected in between making the mouse noises, Mic will go back to sleep and stop making noises. All the components are located on for mounting the stand. Australia's electronics magazine There is a brief 5ms delay between each mouse sound ceasing and the beginning of monitoring ambient noises at the AN5 input. This wait is to prevent the MEMS microphone from picking up sounds from the piezo transducer. Adding up the total current draw taking into account the typical sleep, checking for ambient sound and the mouse sounds operation periods, we estimate the overall current draw is an average of 105μA. It is checking for ambient noise (drawing 1mA) around 9% of the time, making mouse sounds (1.6mA) around 1% of the time and in sleep mode (0.36μA) 90% of the time. Considering a typical 3V cell has a capacity of 200mAh, we expect Mic the Mouse to operate on the one cell for around 1905 hours. That’s 79 the rear of the PCB along with the slots August 2025  63 Mic the Mouse with his stand shown separately. Note the use of a spacer to secure the coin cell. days if Mic is left on continuously. If power is switched off, the current draw from the cell becomes close to zero, with the only draw being cell leakage and diode D1’s reverse leakage. These are very low and in the nanoamps (nA) region. If you handle the cell with your fingers across the insulating ring between the positive and negative contact areas, the leakage current can be higher due to skin oils bridging the terminals. Cleaning the cell with methylated spirits or similar will prevent this extra leakage from occurring. 1 double-sided plated-through white PCB coded 08105251, 96 × 53mm 1 double-sided-plated through white stand PCB coded 08105252, 48 × 31mm 1 Fermion MEMS microphone module (MIC1) [Core Electronics SEN0487] 1 30 × 5.5mm passive piezo transducer (PB1) [HYR-3006/AT3040] 1 SIL SPDT mini vertical slider switch (S1) [SS12D00G3] 1 4-pin 6.2×6.5mm tactile switch (S2) [SKHMQME010 or similar] 1 CR2032 surface-mount folded phosphor bronze PCB mount cell holder (BAT1) [BAT-HLD-001 or similar] 1 CR2032 3V lithium cell 1 3-pin header, 2.54mm pitch (usually supplied with the MEMS microphone) 1 260mm length of white 0.8mm diam. bamboo cord [Spotlight 80325284] 5 M3 × 10mm nylon or polycarbonate screws (cheese or countersunk head) 4 M3 nylon or polycarbonate hex nuts 2 M3 nylon, polycarbonate or metal hex nuts 1 M3 × 6.3mm tapped nylon standoff/spacer Semiconductors 1 PIC16F15214-I/SN 8-bit micro programmed with 1810525A.HEX (IC1) 1 SMD 75V 500mA fast signal diode, such as 1N4148WS or LL4148 (D1) 1 3mm standard brightness red LED (LED1) Capacitors (all SMD M2012/0805 or M3216/1206) 1 1μF 50V X7R 1 100nF 50V X7R Resistors (all SMD M2012/0805 ⅛W or M3216/1206 ¼W) 1 10kW 1% 2 1kW 1% 1 100W 1% component overlay diagram is shown in Fig.2. Check that the tabs on the stand fit into the Mouse slots before assembly. If it is difficult to fit the two together, a small amount of filing may be necessary. The stand should be removed while installing parts on the Mouse PCB. If you are going to use countersunk screws, the front of the PCB will need its holes countersunk so that the screw heads fit neatly, almost flush with the PCB face. Begin by installing the microcontroller (IC1), which comes in an 8-pin SOIC SMD package. You will need a soldering iron with a fine tip, a magnifier and good lighting. First, place the chip with its pin 1 locating dot to the lower right and with the IC leads aligned with the pads. Then solder a corner lead and check that it is still aligned correctly. If it needs to be realigned, remelt the soldered connection and move the IC to align it again. When correct, solder all the remaining pins. Any solder that runs between the IC pins can be removed with solder-wicking braid (ideally with the aid of a little flux paste). Continue by installing the resistors. These will have value codes printed on them, with the last number indicating how many zeroes follow. For the resistors used, the codes will be 101, 100R or 1000 for 100W, 102 or 1001 for 1kW and 103 or 1002 for 10kW. Two resistors and one capacitor are located beneath the MEMS microphone module, so these need to be Complete Kit (SC7508, $37.50): includes everything except the CR2032 cell siliconchip.com.au Construction The parts for Mic the Mouse fit on a double-sided plated-through PCB coded 08105251, measuring 96 × 53mm, with a white solder mask and black labelling. The rear stand plugs into the component side of the Mouse PCB to support it; it is also a PCB, coded 08105252, that measures 48 × 31mm. The main Parts List – Mic the Mouse installed before the MEMS module is in place. The 100nF and 1μF capacitors can be soldered in next; their orientations do not matter. These will not be marked with values, but the 1μF capacitor is likely to be thicker than the other. Diode D1 can now be installed, taking care to orientate correctly. There is sufficient tinned copper area to allow MiniMELF/SOD-80 or SOD-323 package devices to be soldered in. S1 is a through-hole slide switch but you should insert its pins into the allocated holes high off the PCB so the leads don’t protrude through to the other side of the PCB. You can then solder the switch pins to the top side of the pads, not the underside, keeping the visible side of Mic unmarred by solder joints. The on-­ position for this switch is marked on the silkscreen. Switch S2 is surface-mounting tactile pushbutton switch, so solder its four corner pins to the pads. The two mounting holes on the MEMS module need to be drilled out to 3mm to allow the module to be raised off the PCB using nuts as spacers, and secured with M3 machine screws and nuts. The MEMS microphone module is connected electrically using a standard 3-pin 0.1-inch/2.54mm pitch header. Solder this header initially on the component side of the mouse PCB, with the lead ends flush with the non component side, like with the slide switch. After that, slide the black plastic spacer off the pins. Before soldering the MEMS microphone module, attach it to the mouse PCB using M3 nylon or polycarbonate screws and nuts, with the screw heads on the non-component side and one nut securing the screw to the PCB on the component side. The MEMS module is then placed on the screws and two more nuts added to hold the module in place. Do not use metal nuts as they could cause short circuits. With the module attached with the screws, you can then solder the three pins to the pads on the MEMS microphone module. The cell holder is mounted with the cell entry side towards the mouse's ears. That allows the cell capture screw to keep the cell in place, preventing small children from removing it. This complies with Australian Standard AS/NZS ISO 8124.1:2002. While Mic the Mouse is not really a project for very young children, it could be used in a household where young children live or visit, who could potentially swallow button cells if they find one and manage to remove it. For our project, the cell is held within a compartment, with the exit blocked by a 10mm M3 screw that is inserted from the non-component side of the PCB and secured on the cell holder side with a 6.3mm-long nylon tapped standoff. When tightened with a screwdriver, the standoff cannot easily be removed by hand. An alternative to the standoff is two M3 nuts, with the top one used as a lock nut. The cell holder is a half-shell type; its metal contacts the positive side of the cell. A tinned copper area on the PCB completes the cell holder, providing the negative connection to the cell. LED1 is a leaded component, with its leads bent so that they are U-shaped, returning past the LED body. The LED’s lens is positioned over the mouse’s eye hole; it does not protrude through the hole fully. Solder the leads from the component side and make sure the (longer) anode lead is soldered to the pad on the PCB marked “A”. The wires for the piezo can be soldered to the PCB (the positions are marked ‘piezo’). The wires will need to be cut shorter than supplied. The wires will probably be red and black, but it does not matter which colour wire goes to which PCB pad. Typically, including in this case, the transducer is not used as a polarised component. You will need to drill the mounting holes on the piezo unit out to 3mm to suit the M3 screws. The piezo transducer is then secured with two 10mm-long M3 screws and two nylon, polycarbonate or metal nuts. Now insert the CR2032 cell into its holder, secure it with the screw and M3 tapped standoff and switch on the power with switch S1. If all is well, the eye LED will momentarily flash to acknowledge power has been connected. The eye also very briefly flashes at the end of each sleep cycle. Programming IC1 That test assumes IC1 has already been programmed, which it will be if you buy it from us, either by itself or as part of a kit. If you intend to program the PIC yourself, the firmware (1810525A.HEX) can be downloaded from siliconchip.au/Shop/6/2698 If the chip has already been soldered to the board, but is unprogrammed, you will need to wire up a programming adaptor to the PCB, such as a PICkit. Since there is no in-circuit serial programming (ICSP) header, you will need to make the Fig.2: there are about 14 different components mounted on the PCB; don’t miss the three that are under the MEMS microphone module. The five pads numbered 1-5 in red are the points you can solder wires to for in-circuit programming of IC1. They correspond to pins 1-5 of a PICkit programmer or similar. siliconchip.com.au Australia's electronics magazine August 2025  65 five connections separately. They go to pads marked 1-5 on the PCB and in Fig.2; these correspond to the pins on the PICkit programming header (1 = MCLR etc). Sensitivity to sound As mentioned previously, sensitivity to ambient sound can be adjusted so that you can select the sound level that Mic reacts to, over a range of 1-10. Lower values provide higher sensitivity to sound, ie, Mic will detect lower noise levels. Higher values mean less sensitivity, so more noise is required to silence Mic. To adjust sensitivity, switch it on using S1 while holding down S2. This initiates the adjustment mode, where Mic’s eye blinks out the sensitivity setting. There is one blink for each sensitivity level. You can test each sensitivity level after the flashes have finished; you have up to 16 seconds to test each level. The eye will flash in response to your making noises. If the eye continuously flashes due to the detection of background noises, the setting is too sensitive, and a higher value should be selected. To change to the next sensitivity level, press S2 before the 16 seconds are up. This will cause the eye to flash out the next sensitivity level. You can then test this sensitivity level for up to 16 seconds. Once the sensitivity value has reached 10, the next value will be 1 again. The selected sensitivity is stored in flash memory, and will be remembered if the power is switched off. If you wait out the 16 seconds after releasing S2, Mic will begin to make squeaking sounds. This is a quick way to have Mic make some sounds for testing. While making these sounds, Mic also checks whether there is ambient sound. If detected, any mouse sounds will cease, causing him to go to sleep. On a normal power-up without S2 pressed, mouse sounds will begin after about four minutes from switch-on. This period will also depend on whether there is ambient noise present that would prevent Mic from sounding. Further mouse sounds could occur up to two hours later. Adding some whiskers Versatile The whiskers are made using white 0.8mm bamboo cord. The whiskers can be up to about 30mm in length, so cut each length of cord to about 65mm, allowing two whiskers to be formed by folding the length in half. Then insert each end into two adjacent holes in the whisker region, from the component side of the mouse. Coat the cords with a thin smear of PVA glue so that they will become stiff when dry. You will need to orientate the whiskers by having the mouse body supported on a stand so that the PCB sits horizontally, with the whiskers hanging downward until the glue is dry. Finally, the rear stand can be attached at the component side with its two protrusions placed into the slots on mouse PCB. The piezo wire leads will add some holding force to keep the stand in place. Modifications If you want to reduce the volume of the mouse squeaks, increase the resistance of the resistor in series with the piezo transducer. Increasing it from 100W to 1kW will reduce the apparent volume by about 50%. Higher values will provide an even lower volSC ume level. Battery Checker This tool lets you check the condition of most common batteries, such as Li-ion, LiPo, SLA, 9V batteries, AA, AAA, C & D cells; the list goes on. It’s simple to use – just connect the battery to the terminals and its details will be displayed on the OLED readout. Versatile Battery Checker Complete Kit (SC7465, $65+post) Includes all parts and the case required to build the Versatile Battery Checker, except the optional programming header, batteries and glue See the article in the May 2025 issue for more details: siliconchip.au/Article/18121 66 Silicon Chip Australia's electronics magazine siliconchip.com.au